FR3128676A1 - METHOD FOR CONTROLLING THE LOCKING IN THE PARK POSITION OF A TRANSMISSION OF A MOTOR VEHICLE - Google Patents

Abstract

The invention relates to a method for controlling (1) a locking pin of a transmission for a motor vehicle and enabling a parking brake of said motor vehicle to be engaged. Advantageously, the control method takes into account an inclination (P) of the motor vehicle associated with a speed (V) of said motor vehicle. Several cycles (C1, C2, C3) are planned in order to define several pairs of reference inclinations (P1, P2, P3) and threshold speeds (V1, V2, V3, V4) to determine the precise conditions of engagement of the parking brake. Fig. 2

Description

METHOD FOR CONTROLLING THE LOCKING IN THE PARK POSITION OF A TRANSMISSION OF A MOTOR VEHICLE

The technical context of the present invention is that of motor vehicle parking brakes, and more particularly, controlled parking brakes. More particularly, the invention relates to a method for controlling the locking in the parking position of a transmission of a motor vehicle, as well as to such a transmission thus controlled and to a motor vehicle comprising such a transmission.

Certain regulations in certain countries, require that - when the vehicle is parked stationary, it is possible for the driver to formally lock the kinematic chain of a transmission of the motor vehicle in order to immobilize the wheels and to maintain the motor vehicle stopped in all circumstances. In particular, locking the transmission generally consists of applying sufficient force or torque to the kinematic chain connected to the wheels in order to block them. Such locking must make it possible to resist many external forces which would apply to the motor vehicle, such as for example those resulting from the slope of the ground on which the motor vehicle is parked, from the wind, from people or from means which would attempt to pushing or towing the motor vehicle, intentionally or not.

To this end, it is known to equip a motor vehicle with a hindrance device which makes it possible to selectively lock or unlock the transmission chain. In general, the obstruction device consists of a locking "parking finger" or blocking finger, which is configured to be able to be inserted into a housing delimited between two adjacent or consecutive teeth belonging to a constituent element of the transmission.

In general, such devices are known as a parking brake.

Additionally, methods are also known for controlling a parking brake comprising assistance with unlocking, or unlocking, which takes into account the mass of the vehicle and the slope of the ground on which the vehicle is parked.

Such parking brakes thus make it possible to secure the motor vehicle, when the latter is stopped. On the other hand, the known control methods do not take into account a speed of the motor vehicle, so that, if the control method leads to the locking of the transmission chain while the motor vehicle is in motion, this activation can lead damage to the motor vehicle.

The object of the present invention is to propose a new method for controlling a parking brake in order to respond at least in large part to the above problems and also to lead to other advantages.

Another object of the invention is to protect the parking brake system, and in particular the transmission chain and the parking finger of the motor vehicle.

Another object of the invention is to limit the forces appearing on the parking brake system when it is activated.

The invention according to a first aspect of the invention addresses particularly, but not exclusively, a transmission of a motor vehicle comprising:

- A parking toothed wheel coupled in rotation to at least one wheel of the vehicle;

- a finger for locking the parking toothed wheel in rotation, the locking finger being configured to be able to take: (i) a first position – called active – for locking in rotation in which the locking finger is received between two teeth of the parking toothed wheel, and (ii) a second position – called passive – for releasing the parking toothed wheel;

- A locking finger drive actuator between its active and passive positions;

- A motor coupled in rotation to the parking toothed wheel and configured to be able to apply a torque to it.

In accordance with the invention, at least one of the aforementioned objectives is achieved with a method for controlling the locking in the parking position of such a transmission and in which, when a piloting action is established in order to pilot the actuator drive to move the locking finger from its passive position to its active position, the control method comprises (i) a step of determining the speed of movement of the motor vehicle, (ii) a step of determining a inclination of the motor vehicle and (iii) at least one cycle, each cycle comprising:

- a step of comparing the inclination of the motor vehicle with a reference inclination of the cycle;

- if the inclination of the motor vehicle is greater than the reference inclination of the cycle, a phase of comparison of the speed of movement of the motor vehicle with a first threshold speed of the cycle, the engagement action of the actuator d training being canceled and the locking finger being maintained in its passive position if the speed of the motor vehicle is greater than the first threshold speed of the cycle.

The wheel of the motor vehicle is coupled in rotation to the toothed parking wheel, the toothed parking wheel itself being coupled in rotation to a transmission chain of the motor vehicle comprising a plurality of toothed wheels coupled to each other and making it possible to transmit a torque to the wheel of the motor vehicle. In general, the transmission chain comprises, for example, a gearbox and/or a clutch.

The motor coupled in rotation to the parking toothed wheel and allowing a torque to be applied to it is of the type of an electric motor or a heat engine.

When the locking finger is in its active configuration, it blocks the rotation of the toothed wheel of the transmission and, subsequently, the wheel of the motor vehicle, thus providing the desired parking brake effect. Conversely, when the locking finger is in its inactive configuration, the toothed wheel of the transmission is free to rotate and can drive the wheel of the motor vehicle.

The actuator allows the blocking pin to be configured in one or other of its positions. The actuator is controlled by a control action which takes the form of a control signal configuring the actuator in order to cause it to switch selectively into a first configuration which leads to configuring the blocking finger in its active position or in a second configuration which leads to configuring the blocking finger in its inactive position.

The step of determining the speed of movement of the motor vehicle can be carried out by any means making it possible to establish the speed of the motor vehicle. By way of non-limiting example, the step of determining the speed of movement comprises for example a step of reading an indicator representative of the speed available on a communication network of the motor vehicle, or a step of measuring the motor vehicle speed via a speed sensor.

The step of determining the inclination of the motor vehicle can be carried out by any means making it possible to establish the inclination of the motor vehicle. By way of non-limiting example, the step of determining the inclination comprises for example a step of reading an indicator representative of the inclination available on a communication network of the motor vehicle, or a step of measuring the inclination of the motor vehicle by means of an inclinometer.

Of course, in the sense of the invention, the inclination here is taken in a longitudinal direction of the motor vehicle, that is to say the inclination of the surface along which said motor vehicle is moving. In particular, the inclination here takes the value of a slope formed by a mean plane defined by bearing zones of the wheels of the motor vehicle with the surface on which it rests or moves, in a direction perpendicular to the direction of advancement or parking of the motor vehicle, taken between the front and the rear of said motor vehicle.

According to the invention, each cycle comprises a step of comparing the inclination with a reference inclination associated with the cycle in question, and a phase of comparing the speed of the motor vehicle with respect to the first threshold speed associated with the cycle in question .

According to the invention in accordance with its first aspect, the control method comprises one or more of these cycles. In the case where it comprises several cycles, the following cycles, called cycles of lower rank, are executed after the preceding cycles, called cycles of higher rank.

Thus, the invention in accordance with its first aspect takes into account an unprecedented parameter compared to the control methods known hitherto: the speed of the motor vehicle. Subsequently, the control process makes it possible to protect the locking finger, the transmission chain and, in general, the parking brake, in the event of uncontrolled use at unsuitable speeds. In other words, the parking brake is not engaged if, for a given slope, the speed of the motor vehicle is greater than a first predetermined threshold speed.

The control method in accordance with the first aspect of the invention advantageously comprises at least one of the improvements below, the technical characteristics forming these improvements being able to be taken alone or in combination:

- for each cycle, if the speed of the motor vehicle is less than or equal to the first threshold speed of the cycle, then the engagement action of the drive actuator is authorized and the locking finger is moved from its passive position to its active position. Thus, in the case where the speed of the motor vehicle is lower than the first threshold speed, for a given inclination, then the parking brake is activated and the transmission chain is blocked by the blocking finger;

- for each cycle, if the inclination of the motor vehicle is less than the reference inclination of the cycle, the cycle comprises a phase of comparison of the speed of movement of the motor vehicle with a second threshold speed of the cycle, the action of engagement of the drive actuator being canceled and the locking pin being maintained in its passive position if the speed of the motor vehicle is greater than the second threshold speed of the cycle, or the engagement action of the actuator d training being authorized and the locking finger being moved from its passive position to its active position if the speed of the motor vehicle is lower than the second threshold speed of the cycle.

the method comprises a plurality of cycles ordered according to a rank, a cycle of lower rank being carried out after a cycle of a directly higher rank if the speed of the motor vehicle is greater than the second threshold speed of the cycle of higher rank. In particular, a cycle of lower rank is carried out if the conditions of inclination and speed of the cycle of directly higher rank have not been met. In other words, a cycle of lower rank is carried out if the inclination of the motor vehicle is lower than the reference inclination of the cycle of directly higher rank and if the speed of the motor vehicle is higher than the second threshold speed of said cycle of immediately superior rank. This advantageous configuration thus makes it possible to determine several cascading conditions for the triggering of the parking brake by actuation of the locking finger, depending on the inclination and the speed of the motor vehicle. In other words, this advantageous configuration makes it possible to define a plurality of couples {tilt; speed} of the motor vehicle, for which a condition is predetermined for the triggering of the parking brake by activation of the locking finger by the drive actuator;

- for a given cycle, the first threshold speed is lower than the second threshold speed;

- a first threshold speed of a cycle of lower rank is greater than a first threshold speed of a cycle of higher rank; and a second threshold speed of a cycle of lower rank is greater than a second threshold speed of a cycle of higher rank;

- a reference inclination of a cycle of lower rank is less than a reference inclination of a cycle of higher rank.

- the reference inclination of a first cycle with the highest rank is between 10% and 20%. Preferably, it is equal to 15%;

– the first threshold speed of a first cycle with the highest rank is equal to 0.5 km/h, and the second threshold speed of the first cycle with the highest rank is equal to 5 km/h. In general, the first and second threshold speeds of all cycles are less than or equal to 20 km/h. More particularly, the first and second threshold speeds of all the cycles are less than or equal to 5 km/h;

– for a given cycle, the second threshold speed is greater than the first threshold speed by at least a factor of 2, preferably by a factor of 5 and even more preferably by a factor of 10. These particular values make it possible to define several cycles and several conditions for triggering the parking brake by activating the locking finger sufficiently distinct from the others;

- the reference inclination and/or the first and second threshold speeds of each of the at least one cycle are recorded in a memory of a control unit configured to implement the control method;

- during a period of iterations starting from the generation of the engagement action of the drive actuator, the control method implements the step of determining the speed of movement and the step of determination of the inclination of the motor vehicle, and if the inclination of the motor vehicle is less than the first threshold speed, then the engagement action of the drive actuator is authorized and the locking finger is moved from its passive position to its active position. This advantageous configuration makes it possible to be able to automatically activate the parking brake when the speed condition is finally verified during the iteration period, following a single generation of the engagement action of the drive actuator of the locking finger, that is to say following a single parking brake application by the user of a motor vehicle on which the control method is implemented. Preferably, the iteration period is less than or equal to one minute.

According to a second aspect of the invention, there is proposed a control unit configured to implement the control method in accordance with the first aspect of the invention or according to any one of its improvements.

According to a third aspect of the invention, a motor vehicle transmission is proposed, the transmission comprising:

- A parking toothed wheel coupled in rotation to at least one wheel of the vehicle;

- a finger for locking the parking toothed wheel in rotation, the locking finger being configured to be able to take: (i) a first position – called active – for locking in rotation in which the locking finger is received between two teeth of the parking toothed wheel, and (ii) a second position – called passive – for releasing the parking toothed wheel;

- A locking finger drive actuator between its active and passive positions;

- An electric motor coupled in rotation to the parking toothed wheel and configured to be able to apply a torque to it;

- a control unit according to the second aspect of the invention.

According to a fourth aspect of the invention, there is proposed a motor vehicle comprising a transmission in accordance with the third aspect of the invention.

Various embodiments of the invention are provided, integrating according to all of their possible combinations the various optional characteristics set out here.

Other characteristics and advantages of the invention will become apparent through the description which follows on the one hand, and several embodiments given by way of indication and not limiting with reference to the appended diagrammatic drawings on the other hand, on which :

illustrates a first alternative embodiment of the control method in accordance with the first aspect of the invention and comprising a single cycle;

illustrates a second alternative embodiment of the control method in accordance with the first aspect of the invention and comprising two or more cycles,

Of course, the characteristics, the variants and the different embodiments of the invention can be associated with each other, according to various combinations, insofar as they are not incompatible or exclusive of each other. In particular, variants of the invention may be imagined comprising only a selection of characteristics described below in isolation from the other characteristics described, if this selection of characteristics is sufficient to confer a technical advantage or to differentiate the invention from to the state of the prior art.

In particular, all the variants and all the embodiments described can be combined with each other if nothing prevents this combination from a technical point of view.

In the figures, the elements common to several figures retain the same reference.

With reference to FIGURES 1 and 2, the invention in accordance with its first aspect relates to a method 1 for controlling the locking in the parking position of a transmission for a motor vehicle. The transmission is not shown in the FIGURES. Such transmission includes:

- A parking toothed wheel coupled in rotation to at least one wheel of the vehicle;

- a finger for locking the parking toothed wheel in rotation, the locking finger being configured to be able to take: (i) a first position – called active – for locking in rotation in which the locking finger is received between two teeth of the parking toothed wheel, and (ii) a second position – called passive – for releasing the parking toothed wheel;

- A locking finger drive actuator between its active and passive positions;

- An electric motor coupled in rotation to the parking toothed wheel and configured to be able to apply a torque to it.

Thus, when the locking finger is configured in its active position, the transmission of the motor vehicle is locked in rotation, as well as the wheel of said motor vehicle. This situation is the one in which the parking brake of the motor vehicle is engaged following the request of the user. Conversely, when the locking finger is configured in its inactive position, the transmission of the motor vehicle is free to rotate, as is the wheel of said motor vehicle. This is the situation in which the parking brake of the motor vehicle is not engaged.

In accordance with the invention, the control method is consecutive to the appearance of a piloting action 2 leading to piloting the drive actuator of the actuating finger to cause said blocking finger to pass from its passive position to its active position. In the context of the invention, the steering action 2 is induced by the activation by the user of the motor vehicle of the parking brake.

Consequently, the control method 1 comprises:

- A step 11 of determining the speed of movement V of the motor vehicle;

- a step 12 of determining an inclination P of the motor vehicle;

- and at least one cycle C, C1, C2, C3 each cycle C, C1, C2, C3 comprising:

- a comparison step CP1, CP2, CP3 of the inclination P of the motor vehicle with a reference inclination P1, P2, P3 of the cycle C, C1, C2, C3 considered;

- if the inclination P of the motor vehicle is greater than the reference inclination P1, P2, P3 of the cycle, a comparison phase CV1, CV2, CV3 of the speed V of movement of the motor vehicle with a first threshold speed V1, V3 of the considered cycle C, C1, C2, C3, the engagement action of the drive actuator being canceled 14 and the locking finger being maintained in its passive position if the speed V of the motor vehicle is greater than the first threshold speed V1, V3 of said cycle C, C1, c2, C3.

Otherwise, for each cycle C, C1, C2, C3, during the comparison phase CV1, CV2, CV3 of the speed V of movement of the motor vehicle, if the speed V of the motor vehicle is less than or equal to the first speed V1, V3 threshold of the cycle, then the engagement action of the drive actuator is authorized 15 and the locking finger is moved from its passive position to its active position. Thus, in the case where the speed V of the motor vehicle is lower than the first threshold speed V1, V3, for a given inclination P of the motor vehicle, then the parking brake is activated and the transmission chain is blocked by the finger of blockage.

Additionally, for each cycle C, C1, C2, C3, if the inclination P of the motor vehicle is less than the reference inclination P1, P2, P3 of the cycle C, C1, C2, C3 considered, the cycle C, C1 , C2, C3 comprises a comparison phase CV1, CV2, CV3 of the speed V of displacement of the motor vehicle with a second threshold speed V2, V4 of the cycle C, C1, C2, C3:

- if the speed V of the motor vehicle is greater than the second threshold speed V2, V4 of the cycle C, C1, C2, C3, then the engagement action of the drive actuator is canceled 14 and the locking finger being held in its passive position; Or

- if the speed V of the motor vehicle is lower than the second threshold speed V2 of the cycle C, C1, C2, C3, then the engagement action of the drive actuator being authorized 13 and the locking finger being moved from its passive position to its active position.

Thus, and as particularly illustrated in the , the control method 1 according to the invention makes it possible to control the locking finger of the transmission chain of the motor vehicle following the request to engage the parking brake by a user of the motor vehicle, depending first of all on the inclination P of the motor vehicle, then according to its speed V. In this first embodiment illustrated in the , the control method implements a single cycle in which a single reference inclination value P1 is considered:

– if the inclination P of the motor vehicle is greater than the reference inclination P1, then the comparison phase CV1 of the speed of the motor vehicle forms a first comparison phase CV1 during which the speed V of the motor vehicle is compared with the first threshold speed V1 associated with this reference inclination P1. If the speed V is lower than the first threshold speed V1, then the blocking finger can be engaged in its active position without danger for it or the transmission chain, result of the authorization 15 of the engagement action of said finger blockage. Otherwise, the blocking finger is maintained in its inactive position, the result of the cancellation 14 of the engagement action of the blocking finger;

– if the inclination P of the motor vehicle is less than the reference inclination P1, then the speed V of the motor vehicle is compared with a second threshold speed V2 associated with this reference inclination P1. If the speed V is lower than the second threshold speed V2, then the blocking finger can be engaged in its active position without danger for it or the transmission chain, result of the authorization 13 of the engagement action of said finger blockage. Otherwise, the blocking finger is maintained in its inactive position, the result of the cancellation 14 of the action of engaging the blocking finger.

Of course, the second threshold speed V2 is greater than the first threshold speed V1, since the inclination P of the motor vehicle in the case of the comparison with the second threshold speed V2 is lower than that of the motor vehicle in the case of the comparison at the first threshold speed V1. By way of example, the first threshold speed V1 is equal to 0.5 km/h, and the second threshold speed V2 is equal to 5 km/h.

The first reference inclination CP1 implemented in the example embodiment illustrated in the is preferably equal to 15%.

In a particularly advantageous manner, in the context of the invention, it is possible to provide a plurality of conditions on the inclination P of the motor vehicle and, for each condition of inclination P, conditions of speed V of the motor vehicle. These conditions are checked one after the other according to the previous results of these conditions.

Such conditions successively provided one after the other each form a cycle C, C1, C2, C3 of the control method 1 which is the subject of the present invention. Thus, in the , the control method 1 comprises only a single cycle C, C1 determined by a single step of comparison CP1 on the inclination P of the motor vehicle.

On the other hand, the illustrates a more general embodiment of the control method 1 according to the invention, the control method comprising a plurality of cycles C, C1, C2, C3 nested one after the other according to the comparison steps CP1, CP2, CP3 of the inclination P of the motor vehicle.

Thus, the repeats the same steps as those described in connection with the . However, in the event that, in the first cycle CP1, if the inclination P of the motor vehicle is less than the reference inclination P1 associated with the first cycle CP1 and the speed V of the motor vehicle is greater than the second threshold speed V2 of the first cycle CP1, then rather than simply canceling the engagement action of the locking finger to maintain it in its inactive position, a second cycle C2 is engaged in order to verify a second condition on the inclination P of the motor vehicle :

– if the inclination P of the motor vehicle is greater than the reference inclination P2 of the second cycle C2, then the second cycle C2 comprises a new first phase of comparison CV3 of the speed V of the motor vehicle with a new first threshold speed V3 associated with this second cycle C2 and this second cycle C2 reference inclination P2. If the speed V is lower than the first threshold speed V3 of the second cycle C2, then the blocking finger can be engaged in its active position without danger for it or the transmission chain, result of the authorization 15 of the action of engagement of said locking finger. Otherwise, the blocking finger is maintained in its inactive position, the result of the cancellation 14 of the engagement action of the blocking finger;

– if the inclination P of the motor vehicle is less than the reference inclination P2 of the second cycle C2, then the speed V of the motor vehicle is compared with a new second threshold speed V4 of the second cycle C2 and associated with this reference inclination P2 second cycle C2. If the speed V is lower than the second threshold speed V4 of the second cycle C2, then the locking finger can be engaged in its active position without danger for it or the transmission chain, resulting from the authorization 13 of the action of engagement of said locking finger. Otherwise, if the control method 1 does not include other cycles C, C1, C2, C3, then the locking finger is maintained in its inactive position, a result of the cancellation of the engagement action of the locking finger. On the other hand, if the control method 1 comprises a new third cycle C3 established from the comparison of the inclination P of the motor vehicle with a third reference inclination P3, then the control method 1 continues by verifying new conditions similar to what was presented previously for the first C1 and second C2 cycle.

Of course, each threshold speed V1, V2, V3 of a cycle C, C1, C2, C3 of lower rank is greater than a threshold speed V1, V2, V3 of a cycle C, C1, c2, C3 of higher rank . By way of non-limiting example, a threshold speed V1, V2, V3 of a directly lower rank is equal to 1.5 times the threshold speed V1, V2, V3 of the directly higher rank.

Additionally, each reference inclination P1, P2, P3 of a cycle C, C1, C2, C3 of lower rank is less than a reference inclination P1, P2, P3 of a cycle C, C1, c2, C3 of rank superior. By way of non-limiting example, a reference inclination of a directly lower rank is equal to 0.75 times the reference inclination P1, P2, P3 of the directly higher rank.

In the context of the invention, the first cycle has a higher rank than that of the second cycle C2 and that of the third cycle C3. Similarly, the third cycle C3 has a lower rank than the second cycle C2 and the first cycle C1.

Optionally, according to a particularly advantageous embodiment, following the appearance of the control action 2 conducted in order to control the drive actuator to cause the blocking finger to pass from its passive position to its active position, the all of the cycles C, C1, C2, C3 of the control method 1 are performed iteratively 16 during a given iteration period, following the step 11 of determining the speed V and the step 12 of determining the inclination P of the motor vehicle. In other words, following the request to activate the parking brake, leading to the generation of the control action 2 of the locking finger, the cycle or cycles C, C1, C2, C3 of the control method are carried out iteratively 16 and at a given iteration frequency during the iteration period, as long as the parking brake is not engaged during this iteration period. This configuration thus makes it possible, following a single request to engage the parking brake, to authorize the blocking of the transmission chain as soon as the conditions are satisfied – according to the terms presented previously – during one of the iterations carried out of the different cycles C, C1, C2, C3 of the control method 1 according to the invention.

The iteration period is preferably less than or equal to 1 minute, and the iteration frequency is preferably less than or equal to 10Hz, preferably equal to 1Hz.

In summary, the invention relates to a control method 1 of a locking finger of a transmission for a motor vehicle and enabling a parking brake of said motor vehicle to be engaged. Advantageously, the control method takes into account an inclination P of the motor vehicle associated with a speed V of said motor vehicle. Several cycles are planned in order to define several pairs of reference inclinations P1, P2, P3 and threshold speeds V1, V2, V3, V4 to determine the precise conditions for engaging the parking brake.

Of course, the invention is not limited to the examples which have just been described and many adjustments can be made to these examples without departing from the scope of the invention. In particular, the different characteristics, forms, variants and embodiments of the invention may be associated with each other in various combinations insofar as they are not incompatible or exclusive of each other. In particular, all the variants and embodiments described above can be combined with each other.

Claims (10)

Method (1) of controlling the locking in the parking position of a transmission of a motor vehicle comprising:
- A parking toothed wheel coupled in rotation to at least one wheel of the vehicle;
- a finger for locking the parking toothed wheel in rotation, the locking finger being configured to be able to take: (i) a first position – called active – for locking in rotation in which the locking finger is received between two teeth of the parking toothed wheel, and (ii) a second position – called passive – for releasing the parking toothed wheel;
- A locking finger drive actuator between its active and passive positions;
- A motor coupled in rotation to the parking toothed wheel and configured to be able to apply a torque to it;
characterized in that, when a piloting action is established in order to pilot the drive actuator to cause the locking finger to pass from its passive position to its active position, the control method (1) comprises a step of determining (11) of the speed (V) threshold (V1, V2, V3, V4) of movement of the motor vehicle, a step of determining (12) an inclination (P) of the motor vehicle and at least one cycle (C, C1, C2, C3), each cycle (C, C1, C2, C3) comprising:
- a comparison step (CP1, CP2, CP3) of the inclination (P) of the motor vehicle with a reference inclination (P) (P1, P2, P3) of the cycle (C, C1, C2, C3);
- if the inclination (P) of the motor vehicle is greater than the reference inclination (P) (P1, P2, P3) of the cycle (C, C1, C2, C3), a comparison phase (CV1, CV2, CV3, CV4) of the speed (V) threshold (V1, V2, V3, V4) of movement of the motor vehicle with a first speed (V) threshold (V1, V2, V3, V4) threshold of the cycle (C, C1, C2, C3), the engagement action of the drive actuator being canceled and the locking finger being maintained in its passive position if the speed (V) threshold (V1, V2, V3, V4) of the motor vehicle is greater than the first speed (V) threshold (V1, V2, V3, V4) cycle threshold (C, C1, C2, C3). Control method (1) according to the preceding claim, in which, for each cycle (C, C1, C2, C3), if the threshold speed (V) (V1, V2, V3, V4) of the motor vehicle is less than or equal at the first speed (V) threshold (V1, V2, V3, V4) threshold of the cycle (C, C1, C2, C3), then the engagement action of the drive actuator is authorized and the finger of blocking is moved from its passive position to its active position. Control method (1) according to any one of the preceding claims, in which, for each cycle (C, C1, C2, C3), if the inclination (P) of the motor vehicle is less than the inclination (P) reference (P1, P2, P3) of the cycle (C, C1, C2, C3), the cycle (C, C1, C2, C3) comprises a speed comparison phase (V) threshold (V1, V2, V3 , V4) movement of the motor vehicle with a second speed (V) threshold (V1, V2, V3, V4) cycle threshold (C, C1, C2, C3), the engagement action of the actuator drive being canceled and the locking finger being maintained in its passive position if the speed (V) threshold (V1, V2, V3, V4) of the motor vehicle is greater than the second speed (V) threshold (V1, V2, V3, V4) threshold of the cycle (C, C1, C2, C3), or the engagement action of the drive actuator being authorized and the locking finger being moved from its passive position to its active position if the speed ( V) threshold (V1, V2, V3, V4) of the motor vehicle is lower than the second speed (V) threshold (V1, V2, V3, V4) cycle threshold (C, C1, C2, C3). Control method (1) according to the preceding claim, in which the method comprises a plurality of cycles (C, C1, C2, C3) ordered according to a rank, a cycle (C, C1, C2, C3) of lower rank being carried out after a cycle (C, C1, C2, C3) of directly higher order if the speed (V) threshold (V1, V2, V3, V4) of the motor vehicle is greater than the second speed (V) threshold (V1, V2 , V3, V4) cycle threshold (C, C1, C2, C3) of higher rank. Control method (1) according to the preceding claim, in which a reference inclination (P) (P1, P2, P3) of a cycle (C, C1, C2, C3) of lower rank is less than an inclination ( P) reference (P1, P2, P3) of a cycle (C, C1, C2, C3) of higher rank. Control method (1) according to any one of Claims 3 to 5, in which, for a given cycle (C, C1, C2, C3), the first speed (V) threshold (V1, V2, V3, V4) threshold is lower than the second speed (V) threshold (V1, V2, V3, V4) threshold. A control method (1) according to any preceding claim, wherein during an iteration period starting from generation of the drive actuator engagement action, the control method ( 1) implements the step of determining the speed (V) threshold (V1, V2, V3, V4) of movement and the step of determining the inclination (P) of the motor vehicle, and if the inclination (P) of the motor vehicle is lower than the first speed (V) threshold (V1, V2, V3, V4) threshold, then the engagement action of the drive actuator is authorized and the locking finger is moved from its passive position to its active position. Control unit configured to implement the control method (1) according to any one of the preceding claims. Motor vehicle transmission, the transmission comprising:
- A parking toothed wheel coupled in rotation to at least one wheel of the vehicle;
- a finger for locking the parking toothed wheel in rotation, the locking finger being configured to be able to take: (i) a first position – called active – for locking in rotation in which the locking finger is received between two teeth of the parking toothed wheel, and (ii) a second position – called passive – for releasing the parking toothed wheel;
- A locking finger drive actuator between its active and passive positions;
- An electric motor coupled in rotation to the parking toothed wheel and configured to be able to apply a torque to it;
- A control unit according to the preceding claim. Motor vehicle comprising a transmission according to the preceding claim.