Transmission shaft coupling system and method for controlling such a transmission shaft coupling system

Abstract

Title of the invention: Transmission shaft coupling system and method for controlling such a transmission shaft coupling system. The present invention relates to a method for controlling a transmission shaft coupling system (1) comprising: - a driving shaft; - a driven shaft coaxial with the driving shaft; - a dog clutch sleeve (30) arranged to move along a first axis of rotation (X) to couple the driving shaft with the driven shaft; - an actuation device comprising an electric motor kinematically linked to an output shaft (40) rotating about a second axis of rotation (Y) arranged to pivot within the dog clutch sleeve;The control method comprises the following steps: - rotating the output shaft (40) within a predetermined angular sector of actuation (α) to axially move the dog clutch sleeve (30) from a first extreme disengagement position to a second extreme coupling position of the driving shaft with the driven shaft; - rotating the output shaft (40) within a first additional angular sector (α4). Abstract figure: Figure 4;

Description

Title of the invention: Transmission shaft coupling system and method for controlling such a transmission shaft coupling system

[0001] The present invention relates to the field of transmission shaft coupling systems and in particular a method for controlling such a transmission shaft coupling system.

[0002] The drive shaft coupling system is, for example, integrated into an electric transmission of a motor vehicle, which comprises an electric machine and an associated speed reducer, the coupling system being placed, in particular, between the output of the speed reducer and the wheel of the vehicle. The motor vehicle may be electric or hybrid.

[0003] In a motor vehicle with a hybrid transmission comprising an internal combustion engine and an electric transmission, such coupling systems can be used to connect the electric transmission to the rear wheels of the vehicle when its use becomes necessary to supplement the internal combustion engine, which provides torque and power to the front wheels. Such a driveshaft coupling system is known from document WO2016 / 096769 AL

[0004] In this document, the transmission shaft coupling system is interposed between a drive transmission shaft comprising a first internal spline and a driven transmission shaft coaxial to the drive shaft comprising a second external spline.

[0005] The coupling system also includes a double-grooved dog clutch sleeve adapted to connect the driving shaft to the driven shaft when the use of the electric transmission becomes necessary. The dog clutch sleeve is mounted longitudinally on the driven transmission shaft. The dog clutch sleeve is driven along the axis of rotation of the driven transmission shaft by means of an actuation device comprising an electric motor associated with a speed reduction device, for example, an epicyclic gear train.

[0006] For this purpose, an internal surface of the dog clutch sleeve is provided with an internal groove that couples with the external groove of the driven transmission shaft and an external groove that couples with the internal groove of the driving transmission shaft.

[0007] When the coupling system is in an uncoupling position, the outer spline of the connector is not engaged in the first inner spline of the drive shaft. The drive shaft and the connector have speeds of different rotations. To engage the connection between the driving and driven transmission shafts, the electric motor of the actuation device is used to rotate an eccentric control rod within an annular groove in the dog clutch sleeve. The rotation of the eccentric control rod around a central axis of the epicyclic gear train allows the dog clutch sleeve to move longitudinally.

[0008] When the coupling system is in a coupling position, the rotational speeds of the driven shaft, the driving shaft and the dog clutch sleeve are identical while the side of the eccentric control rod is fixed in rotation.

[0009] It is therefore understood that if the contact pressure between the eccentric control rod and the groove of the dog clutch sleeve remains present during the coupling phase, heating at the point of contact can occur and generate wear, especially if this contact pressure remains maintained over a long period.

[0010] The present invention aims to overcome these drawbacks by proposing a transmission shaft coupling system in which heating at the point of contact is reduced, or even eliminated, between the interface component of the actuation device and the dog clutch sleeve.

[0011] To this end, according to a first aspect of the invention, a method for controlling a transmission shaft coupling system is proposed, comprising:

[0012] - a drive shaft comprising a first spline of transmission;

[0013] - a coaxial transmission driven shaft to the driving shaft comprising a second transmission spline;

[0014] - a dog clutch sleeve comprising at least one first groove of connection capable of driving the driving shaft in rotation along a first axis of rotation and a second spline of connection capable of driving the driven shaft in rotation;

[0015] - an actuation device comprising an output shaft rotating around a second axis of rotation, an interface component disposed at the end of the output shaft and arranged to pivot within a receiving housing formed in the dog clutch sleeve, the dog clutch sleeve being able to move axially along the first axis of rotation between a first extreme disengagement position and a second extreme engagement position when the output shaft pivots through a predetermined angular sector of actuation,

[0016] the control method comprising at least the following successive steps:

[0017] - rotate the output shaft of the actuation device according to the angular sector predetermined actuation point for axially moving the dog clutch sleeve from the first extreme uncoupling position to the second extreme coupling position;

[0018] - and then, rotate the output shaft around a first angular sector additional between 1° and 40°, for example between 5° and 15°, without axial displacement of the dog clutch sleeve, the direction of rotation being identical or opposite to the direction of rotation of the predetermined angular sector of actuation.

[0019] According to the control method of the invention, it is advantageous to reduce the contact pressure between the interface component and the dog clutch sleeve after the teeth have engaged. This prevents heating at the point of contact. A clearance between the interface component and the dog clutch sleeve's receiving housing is easily ensured during the coupling phase of the transmission shafts. During this phase, a relative rotational speed exists between the interface component and the dog clutch sleeve.

[0020] This control method is neutral in terms of the operation of the electric transmission of the motor vehicle because the transmission of torque can take place from the end of the first step of the control method.

[0021] In the case where the direction of rotation of the first additional angular sector is identical to the direction of rotation of the predetermined actuation angular sector, the output shaft of the actuation device pivots beyond the predetermined actuation angular sector and therefore performs a greater angular deflection.

[0022] In the case where the direction of rotation of the first additional angular sector is contrary to the direction of rotation of the predetermined actuating angular sector, the output shaft of the actuating device returns angularly backwards with respect to the first step of the control method.

[0023] Preferably, the first additional angular sector is adjacent to the predetermined actuation angular sector.

[0024] Preferably, the predetermined angular actuation sector is between 20° and 180°.

[0025] According to a variant of the invention, in the case where the direction of rotation of the first additional angular sector is identical to the direction of rotation of the predetermined actuation angular sector, the control method may comprise the following two steps:

[0026] - rotate the output shaft of the actuation device in the direction of rotation contrary to the first step of the control process, according to the first additional angular sector and the predetermined actuation angular sector to axially move the dog clutch sleeve from the second extreme coupling position to the first extreme discoupling position;

[0027] - and then, rotate the output shaft along a second angular sector additional between 1° and 40°, for example between 5° and 15°, without axial displacement of the dog clutch sleeve, the direction of rotation being identical to the direction of rotation of the previous step.

[0028] In this variant, the output shaft of the actuation device performs a greater angular deflection because the overall pivoting of the output shaft combines the first additional angular sector, the predetermined actuation angular sector and the second additional angular sector.

[0029] According to the control method of the invention, it is advantageous to reduce the contact pressure between the interface component and the dog clutch sleeve. This prevents heating at the point of contact. A clearance between the interface component and the dog clutch sleeve's receiving housing is easily ensured during the uncoupling phase of the transmission shafts. During this phase, a relative rotational speed may be present between the interface component and the dog clutch sleeve.

[0030] According to another embodiment of the invention, in the case where the direction of rotation of the first additional angular sector is contrary to the direction of rotation of the predetermined actuation angular sector, the control method may comprise the following two steps:

[0031] - rotate the output shaft of the actuating device in the direction of rotation contrary to the first step of the control process, according to the predetermined angular sector of actuation for which the value of the angle of the first additional angular sector has been subtracted to axially move the dog clutch sleeve from the second extreme coupling position to the first extreme discoupling position;

[0032] - and then, rotate the output shaft along a second angular sector additional between 1° and 40°, for example between 5° and 15°, without axial displacement of the dog clutch sleeve, the direction of rotation being contrary to the direction of rotation of the previous step.

[0033] In this alternative embodiment, the output shaft of the actuation device undergoes a smaller angular deflection because the overall pivoting of the output shaft combines only the second additional angular sector and the predetermined actuation angular sector subtracted from the angle value of the first additional angular sector. The actuation time is reduced for this alternative embodiment of the control method.

[0034] According to the control method of the invention, it is advantageous to reduce the contact pressure between the interface component and the dog clutch sleeve. This prevents heating at the point of contact. This ensures that A simple operating clearance exists between the interface component and the receiving housing of the dog clutch sleeve during the uncoupling phase of the transmission shafts. During this phase, a relative rotational speed may be present between the interface component and the dog clutch sleeve.

[0035] Preferably, the receiving housing of the dog clutch sleeve is an annular groove comprising two parallel flat surfaces.

[0036] According to one aspect of the invention, the interface component is an eccentric actuating rod with respect to the second axis of rotation of the actuating device, the eccentric actuating rod being a cylindrical component which is inserted into the receiving housing (31) of the dog clutch sleeve.

[0037] The eccentric actuating rod can be a rolling bearing, for example a ball bearing or a roller bearing.

[0038] According to another aspect of the invention, the interface component is an actuating cam pivoting with respect to the second axis of rotation of the actuating device which has in section perpendicular to the second axis of rotation a general profile of a Reuleaux triangle, the actuating cam being inserted in the receiving housing of the dog clutch sleeve.

[0039] According to another aspect of the invention, the interface component is an actuating cam pivoting about the second axis of rotation and having two contact areas arranged to press against the parallel flat surfaces of the receiving housing, the first bearing width separating the two contact areas, measured along the first axis of rotation, is constant when the output shaft pivots along the predetermined angular sector of actuation and the actuating cam has a second width separating the two contact areas, measured along the first axis of rotation, less than the first bearing width when the output shaft pivots along the first additional angular sector or along the second additional angular sector adjacent to the predetermined angular sector of actuation.

[0040] The invention also relates to a transmission shaft coupling system comprising:

[0041] - a drive shaft comprising a first spline of transmission;

[0042] - a coaxial transmission driven shaft to the driving shaft comprising a second transmission spline;

[0043] - a dog clutch sleeve comprising at least one first groove of connection capable of driving the driving shaft in rotation along a first axis of rotation and a second spline of connection capable of driving the driven shaft in rotation;

[0044] - an actuation device comprising an output shaft rotating around a second axis of rotation, an interface component located at the end of the shaft output shaft arranged to pivot within a receiving housing formed in the dog clutch sleeve, the dog clutch sleeve being able to move axially along the first axis of rotation between a first extreme disengagement position and a second extreme engagement position when the output shaft pivots through a predetermined angular sector of actuation,

[0045] The receiving housing is an annular groove comprising two parallel flat surfaces,

[0046] wherein the interface component is an actuating cam pivoting about the second axis of rotation and which has two contact areas arranged to press against the parallel flat surfaces of the receiving housing, the first bearing width separating the two contact areas, measured along the first axis of rotation, is constant when the output shaft pivots around the predetermined angular sector of actuation and the actuating cam has a second width separating the two contact areas, measured along the first axis of rotation, less than the first bearing width when the output shaft pivots around a first additional angular sector adjacent to the predetermined angular sector of actuation.

[0047] This driveshaft coupling system reduces the contact pressure between the interface component and the dog clutch sleeve after the gear teeth have engaged. This prevents overheating at the contact point. A simple operating clearance is maintained between the interface component and the dog clutch sleeve's receiving housing during the driveshaft coupling operation. During this phase, a relative rotational speed exists between the interface component and the dog clutch sleeve.

[0048] Advantageously, the actuating cam has in section perpendicular to the second axis of rotation a general Reuleaux triangle profile whose first bearing width separating the two contact zones remains constant over the entire predetermined angular sector of actuation and the profile of the actuating cam locally has at least one flat or concave zone, the at least one flat or concave zone being arranged opposite one of the two parallel flat surfaces of the receiving housing when the output shaft pivots according to the first additional angular sector.

[0049] The invention implements a simple geometry, for example a flat or concave area, at the level of the profile of the actuating cam to ensure an operating clearance between the interface component and the receiving housing of the dog clutch sleeve in the operating phase of coupling the transmission shafts.

[0050] According to one aspect of the invention, the predetermined angular actuation sector consists of three adjacent angular sub-sectors, a first sub-sector angular, a second angular sub-sector which is adjacent to the first angular sub-sector, a third angular sub-sector which is adjacent to the second angular actuation sub-sector,

[0051] and wherein the dog clutch sleeve moves axially between two extreme positions when the output shaft pivots along the entire second angular sub-sector,

[0052] the dog clutch sleeve remaining axially immobile in the first extreme position when the rotation of the output shaft is within the first angular sub-sector,

[0053] and the dog clutch sleeve remaining axially immobile in the second extreme position when the rotation of the output shaft is in the third angular sub-sector.

[0054] This actuation device allows, in particular thanks to the first angular sub-sector and the third angular sub-sector, to have two stable extreme actuation positions because an angular variation of a few degrees on the output shaft does not generate a displacement of the receiving part.

[0055] According to one aspect of the invention, the interface component is an actuating cam pivoting about the second axis of rotation. The actuating cam comprises three actuating faces formed in the form of cylindrical segments, and the three centers of these cylindrical segments form an isosceles triangle. The geometry of the contact areas of the actuating cam uses large-diameter cylindrical segments, thereby reducing the contact pressure with the clutch sleeve.

[0056] For example, the principal vertex of the isosceles triangle can be coincident with the second axis of rotation of the output shaft.

[0057] Preferably, the actuating cam may have a symmetrical actuation profile whose axis of symmetry passes through the bisector of the isosceles triangle, the bisector of the isosceles triangle corresponding to the midpoint of the second angular sector. The actuating cam thus has a symmetrical profile passing through the second axis of rotation of the output shaft.

[0058] The angle value of the second angular sub-sector is strictly less than 180°. Thus, the angular travel of the output shaft is reduced, which has the effect of reducing the actuation time.

[0059] According to one embodiment of the invention, the dog clutch sleeve comprises at least one first internal connecting spline arranged to drive the driving shaft in rotation and a second internal connecting spline arranged to drive the driven shaft in rotation, the first and second internal splines being engaged respectively in a first external transmission spline of the driving shaft and a second external transmission spline of the driven shaft when the dog clutch sleeve is in the second extreme coupling position.

[0060] According to another embodiment of the invention, the dog clutch sleeve comprises at least a first external connecting groove arranged to drive the driving shaft in rotation and a second internal connecting groove arranged to drive the driven shaft in rotation, the first and second internal grooves being engaged respectively in a first internal transmission groove of the driving shaft and a second external transmission groove of the driven shaft when the dog clutch sleeve is in the second extreme coupling position.

[0061] According to one aspect of the invention, an operating clearance is defined between the bearing width of the actuating cam and the distance separating the two parallel flat surfaces of the receiving housing, a first operating clearance J1 being constant when the output shaft pivots according to the predetermined angular sector of actuation and a second operating clearance J2 is greater than the first operating clearance J1 when the output shaft pivots according to the first additional angular sector.

[0062] Preferably, the second operating clearance J2 comprises the sum of the first operating clearance J1 and an additional clearance J3, such that J2 = J1 + J3. The first operating clearance J1 takes into account the general manufacturing tolerances of the dog clutch sleeve and the output shaft.

[0063] The additional clearance J3 is in the order of 0.1 mm to 0.6 mm.

[0064] For example, J2 = J1 + 0.3 mm.

[0065] For example, J2 = J1 + 0.5 mm.

[0066] The actuation device for the transmission shaft coupling system according to the invention may have one or more of the characteristics described below, either combined or taken independently of each other:

[0067] - the actuation device is mounted on a fixing housing;

[0068] - the angle value of the first angular sub-sector is greater than 3°;

[0069] - the angle value of the second angular sub-sector is between 20° and 174°;

[0070] - the angle value of the third angular sub-sector is greater than 3°;

[0071] - the angle value of the first angular subsector is identical to the angle value of the third angular sub-sector;

[0072] - the angle value of the first angular subsector is different from the value angle of the third angular sector.

[0073] The invention also relates to a motor vehicle with hybrid or electric transmission comprising a transmission shaft coupling system as previously mentioned.

[0074] Other features, details and advantages of the invention will become clearer upon reading the following description on the one hand, and the illustrative and non-limiting examples of embodiments given with reference to the accompanying drawings on the other hand, in which:

[0075] [Fig-1] is a cross-sectional view of a transmission shaft coupling system according to a first embodiment of the invention;

[0076] [Fig.2] is a top view of the coupling system actuating cam of transmission shafts of the [Fig.l];

[0077] [Fig.3] is a simplified view of the interface end of the output shaft of the actuation device of the [Fig.l];

[0078] [Fig.4] is another simplified view of the interface end of the output tree having pivoted according to the first additional angular sector a4;

[0079] [Fig.5] is an isometric view of the output shaft of the coupling system of transmission shafts according to a second embodiment of the invention;

[0080] [Fig.6] is an isometric view of the output shaft of the coupling system of transmission shafts according to a third embodiment of the invention.

[0081] The features, variants and different embodiments of the invention can be combined with each other in various combinations, provided that they are not incompatible or mutually exclusive.

[0082] Throughout the description, elements common to several figures retain the same reference.

[0083] In the description and claims, the terms "external" and "internal" and the orientations "axial" and "radial" shall be used to designate, according to the definitions given in the description, elements of the transmission system. By convention, the "radial" orientation is directed orthogonally to the first axis of rotation X of the coupling system determining the "axial" orientation, and, from the inside out and away from said axis, the "circumferential" orientation is directed orthogonally to the first axis of rotation X and orthogonally to the radial direction.

[0084] Figures 1 to 4 illustrate a transmission shaft coupling system 1 according to a first embodiment of the invention. We will first describe the operation of a transmission shaft coupling system in general.

[0085] The driveshaft coupling system 1 is here a connecting clutch between two shafts 2, 3 which is used, in a vehicle's drivetrain, to transmit torque from a thermal or electric motor, not shown, to a wheel shaft 7 of a motor vehicle. Such A driveshaft coupling system can, for example, be part of a secondary drivetrain capable of transmitting torque from a secondary vehicle motor, such as an electric motor, to a rear or front axle, while a primary drivetrain is capable of transmitting torque from a main motor, such as an internal combustion engine, to the wheel shafts of another axle. When the reversible electric machine associated with the speed reducer is inactive, there is no benefit to leaving the electric machine connected to the vehicle wheel. The connecting clutch is then disengaged.

[0086] The transmission shaft coupling system 1 is kinematically interposed between a speed reducer and the wheel shaft 7 of the vehicle. The output of the speed reducer is rotationally fixed to a drive shaft 2 of the transmission about a first axis of rotation X. The drive shaft 2 of the transmission includes a first transmission spline 2a machined on its end; in this example, the first transmission spline is external.

[0087] The transmission shaft coupling system 1 also includes a driven transmission shaft 3 coaxial with the driving shaft 2, comprising a second transmission spline 3a, the second transmission spline being external in this example. The driven shaft 3 is inserted into the driving shaft 2 and guided in rotation by means of a guide bearing 4 around the first axis of rotation X. The driven transmission shaft 3 also includes an internal torque output spline 3b rotationally connected with the wheel shaft 7 of the vehicle.

[0088] The transmission shaft coupling system 1 uses a dog clutch sleeve 30 to connect the two driving and driven shafts 2, 3. The dog clutch sleeve 30 is axially movable about the first axis of rotation X and includes a first connecting spline 33 adapted to drive the driving shaft 2 in rotation and a second connecting spline 34 adapted to drive the driven shaft 3 in rotation. In this example, the first and second connecting splines 33, 34 are external and are complementary to the first and second transmission splines 2a, 3a.

[0089] To actuate the transmission shaft coupling system 1, an electrically powered actuating device 10 is used. The actuating device 10 comprises an electric motor 11 kinematically linked to a speed reduction device 13, an output shaft 40 of the speed reduction device rotating about a second axis of rotation Y, and an interface component 20, for example an actuating cam, disposed at the end of the output shaft which interacts with the dog clutch sleeve 30. The interface component 20 is arranged, in particular, to pivot within a receiving recess 31 formed directly in the dog clutch sleeve 30. The receiving recess 31 of the dog clutch sleeve 30 is in the form of a groove composed of two lateral rims 32 and a cylindrical bottom 35 and receives the interface component of the output shaft.

[0090] As illustrated in [Fig. 1], the interface component 20 is fixed rigidly to the output shaft 40.

[0091] The output shaft 40 is primarily rotary in shape, notably including a cylindrical bearing surface 44 that pivots within the protective housing 18 of the actuation device 10. The output shaft 40 also includes a toothed ring 45, here an external toothed ring that meshes with another gear of the speed reduction device 13. The speed reduction device 13 comprises, in this first embodiment of the invention, a spur gear train. The toothed ring 45 of the output shaft participates in the final speed reduction stage of the electric motor 11.

[0092] This actuation device 10 also includes a protective housing 18 which protects the electric motor 11 and supports the speed reduction device 13. The protective housing 18 is attached to a protective sleeve 9 of the transmission system 1. The protective sleeve 9 is cylindrical in shape with its axis coinciding with the first axis of rotation X and has an opening for the output shaft 40 of the actuation device to pass through.

[0093] As illustrated in [Fig. 3], the dog clutch sleeve 30 moves axially between two extreme disengaged and engaged positions when the output shaft 40 pivots about its second axis of rotation Y within a predetermined angular sector. The dog clutch sleeve 30 moves axially by a value Dx relative to the driven transmission shaft 3, which is axially fixed.

[0094] When the dog clutch sleeve 30 is in the first extreme disengagement position, the second connecting spline 34 is disengaged from the second transmission spline of the driven shaft 3. The second connecting spline 34 is broken to reduce the engagement stroke.

[0095] When the dog clutch sleeve 30 is in the second extreme coupling position, the first and second connecting splines 33, 34 are engaged respectively in the first transmission spline 2a of the driving shaft 2 and the second transmission spline 3a of the driven shaft 3.

[0096] The receiving housing 31 of the dog clutch sleeve 30 has two parallel flat surfaces 32a and receives the interface component 20 of the actuating device. In this case, the interface component is in the form of the actuating cam 20. The two parallel flat surfaces 32a are formed from the same material as the dog clutch sleeve.

[0097] In this first embodiment of the invention, the actuating cam 20 has, in section perpendicular to the second axis of rotation Y, a general profile of Reuleaux triangle. The actuating cam 20 has two contact areas 20a, 20b bearing on the parallel flat surfaces 32a of the receiving housing, a first bearing width L1 along the first axis of rotation X separating the two contact areas is constant over the whole rotation of the output shaft 40 to go from the first extreme disengagement position to the second extreme coupling position.

[0098] To ensure a free movement of the actuating cam 20 within the annular groove without undue friction, a first operating clearance J1 is defined between the bearing width L of the actuating cam and the distance D separating axially along the first axis of rotation X the two parallel flat surfaces 32a of the receiving housing 31.

[0099] As illustrated in [Fig. 2], the actuating cam 20 comprises three actuating faces 21 formed in the form of cylindrical segments. The three centers 22 of these cylindrical segments form an isosceles triangle, the principal vertex of the isosceles triangle coinciding with the second axis of rotation Y of the output shaft 40. The geometry of the contact areas 20a, 20b of the actuating cam utilizes large-diameter cylindrical segments to reduce the contact pressure with the parallel surfaces of the receiving housing. During rotation of the actuating cam, the actuating face 21 slides on one of the parallel surfaces 32. In this first embodiment, the actuating cam 20 has a symmetrical actuating profile whose axis of symmetry passes through the bisector 37 of the isosceles triangle. The isosceles triangle has an altitude H and a principal angle [3 for example between 45° and 150°.The actuation cam 20 thus has a symmetrical profile passing through the second axis of rotation Y.

[0100] To ensure free movement of the actuating cam 20 within the receiving housing 31 without unwanted friction, the actuating faces 21 of the actuating cam 20 are connected to each other by a cylindrical connecting face 23 with a radius R2 smaller than the radius RI of the cylindrical segments, the connecting radius being between 1 and 5 mm. During rotation of the actuating cam, the cylindrical connecting face 23 also slides on one of the parallel surfaces 32. The contact areas 20a, 20b of the actuating cam are alternately formed by an actuating face 21 and / or a cylindrical connecting face 23. The geometry of the contact area 20a, 20b then has a radius RI or a radius R2.

[0101] The actuating cam 20 also includes an end radius R3 arranged to interact with the parallel flat surfaces 32a of the dog clutch sleeve 30 and tangentially connecting two actuating faces 21, the center of this end radius R3 being concentric with the axis of rotation Y. The center of the end radius R3 passes through the bisector 37 of the isosceles triangle. The dimension of the radius R3 is defined in order to respect the first support width Ll. Thus, the sum of the radius RI of the portion of the cylinder forming the actuation face 21 associated with the main vertex of the isosceles triangle and the radius R3 is equal to the first support width Ll.

[0102] In order to recenter the actuating cam 20 in the receiving housing 31, the first axis of rotation X of the dog clutch sleeve 30 is not intersecting the second axis of rotation Y. For example, the second axis of rotation Y is offset with respect to a plane parallel to the second axis of rotation Y and passing through the first axis of rotation X by a value of a few millimeters.

[0103] We will now describe the operation of the actuation device allowing the transition from the first extreme uncoupling position to the second extreme coupling position with a reduced actuation time.

[0104] As illustrated in [Fig.3], the output shaft 40 is arranged to pivot around a predetermined angular actuation sector a consisting of three adjacent angular sub-sectors al, a2, a3, a first angular sub-sector al, a second angular sub-sector a2 which is adjacent to the first angular sub-sector al, a third angular sub-sector a3 which is adjacent to the second angular sub-sector a2.

[0105] Initially, the dog clutch sleeve 30 is in its first extreme disengaged position. The dog clutch sleeve 30 remains axially stationary in this first extreme position when the output shaft rotation is within the first angular sector. The angle of the first angular sub-sector al is 25°. Within this first angular sub-sector al, the dog clutch sleeve 30 remains in a stable position that allows the electrical supply to the actuation device to be cut off, thus reducing the vehicle's electrical consumption.

[0106] In a second step, the dog clutch sleeve 30 moves axially between the two extreme disengagement and engagement positions when the output shaft 40 pivots through the entire second angular sub-sector a2. The displacement Dx of the dog clutch sleeve 30 is shown in [Fig. 3]. The angle value of the second angular sub-sector a2 is approximately 100°.

[0107] In a third step, the dog clutch sleeve 30 remains axially fixed in the second extreme position when the rotation of the output shaft is in the third angular sub-sector a3. The angle value of the third angular sector a3 is 25°. On this third angular sub-sector a3, the dog clutch sleeve 30 remains in a stable position which allows the electrical supply to the actuation device to be cut off, thus reducing the vehicle's electrical consumption.

[0108] Thanks to the particular geometry of the actuating cam profile, the first support width Ll along the first axis of rotation X separating the two zones of The contact 20a, 20b is constant when the output shaft 40 pivots according to the predetermined angular sector of actuation a constituted by the three angular sub-sectors a1, a2, a3. [Fig.3] also illustrates the different angular positions taken by the actuating cam 20 during the displacement Dx of the dog clutch sleeve 30.

[0109] During the operation of the actuation device 10, the interface component 20 applies a force on the parallel flat surface 32a of the receiving housing 31 to move the dog clutch sleeve 30. Even though the actuation face 21 has a large radius RI, a high contact pressure is applied on the parallel flat surface 32a of the receiving housing 31.

[0110] To reduce the contact pressure between the interface component 20 and the dog clutch sleeve 30 after engaging the teeth of the dog clutch sleeve in those of the driven shaft 3, the actuating cam 20 has a second width L2 separating the two contact areas with the parallel flat surfaces 32a, measured along the first axis of rotation X, less than the first bearing width L1 when the output shaft 40 pivots along an additional angular sector a4 adjacent to the predetermined angular actuation sector a.

[0111] We will now describe the method of controlling the transmission shaft coupling system which allows the contact pressure between the interface component 20 and the dog clutch sleeve 30 to be reduced after engaging the teeth of the dog clutch sleeve in those of the driven shaft 3.

[0112] When the transmission shaft coupling system 1 is in the first extreme disengagement position, the electric transmission is stopped. The rotor of the electric machine does not rotate, so the speed of the driving shaft 2 is zero, while the rotational speed of the driven shaft 3 corresponds to that of the vehicle wheels.

[0113] When it is desired to engage the teeth of the internal spline of the dog clutch sleeve 30 within the second transmission spline 3a of the driven shaft 3, the rotational speed of the driving shaft 2 is first adjusted with the setpoint to be as close as possible to the rotational speed of the driven shaft 3, while maintaining a slight speed differential between the two shafts 2, 3. When the setpoint speed of the driving shaft 2 is reached, the teeth of the internal spline of the dog clutch sleeve 30 are inserted.

[0114] To this end, the method for controlling the transmission shaft coupling system 1 comprises the following successive steps:

[0115] - rotate the output shaft 40 of the actuation device along a sector The predetermined angular actuation is used to axially move the sleeve of dog clutching 30 from the first extreme uncoupling position to the second extreme coupling position;

[0116] - and then, rotate the output shaft 40 around a first angular sector additional a4, without axial displacement of the dog clutch sleeve, the direction of rotation being identical to the direction of rotation of the predetermined angular sector of actuation a.

[0117] In this first embodiment of the control method, the angle value of the first additional angular sector a4 is 15° and the first additional angular sector a4 is adjacent to the predetermined actuation angular sector a. The angle value of the predetermined actuation angular sector a is 100°.

[0118] The direction of rotation of the first additional angular sector a4 is identical to the direction of rotation of the predetermined actuation angular sector a. The output shaft 40 of the actuation device 10 pivots beyond the predetermined actuation angular sector a and therefore performs a greater angular deflection.

[0119] Thanks to the second width L2 being smaller than the first support width L1 when the output shaft 40 pivots along the first additional angular sector a4, an additional clearance J3 is easily ensured between the interface component 20 and the receiving housing 31 of the dog clutch sleeve during the coupling operation phase of the transmission shafts. This prevents overheating at the contact point of the actuating cam.

[0120] An operating clearance is defined between the bearing width of the actuating cam and the distance separating the two parallel flat surfaces of the receiving housing. A first operating clearance J1 is constant when the output shaft pivots through the predetermined angular sector of actuation a. The first operating clearance J1 takes into account the general manufacturing tolerances of the dog clutch sleeve and the output shaft.

[0121] A second operating clearance J2 is greater than the first operating clearance J1 when the output shaft pivots along the first additional angular sector a4, and the second operating clearance J2 comprises the sum of the first operating clearance J1 and the additional clearance J3, such that J2 = J1 + J3. The additional clearance J3 is on the order of 0.3 mm and corresponds to the difference between the first bearing width L1 and the second width L2.

[0122] To return to the first extreme disengagement position, the control method for the transmission shaft coupling system 1 has the following successive steps:

[0123] - rotate the output shaft 40 of the actuating device, in the direction of rotation contrary to the first step of the control process, according to the first additional angular sector a4 and the predetermined actuation angular sector a to axially move the dog clutch sleeve 30 from the second extreme coupling position to the first extreme discoupling position;

[0124] - and then, rotate the output shaft 40 along a second angular sector additional a5, without axial displacement of the dog clutch sleeve, the direction of rotation being identical to the direction of rotation of the previous step.

[0125] In this first embodiment of the control method, the angle value of the second additional angular sector a5 is 15° and the second additional angular sector a5 is adjacent to the predetermined actuation angular sector a.

[0126] Thanks to the second width L2 being smaller than the first support width L1 when the output shaft 40 pivots along the second additional angular sector a5, an additional clearance J3 is easily ensured between the interface component 20 and the receiving housing 31 of the dog clutch sleeve during the disengagement phase of the transmission shafts. This prevents overheating at the contact point of the actuating cam.

[0127] We will now describe, with reference to [Fig.5], a second embodiment of the invention, which differs from the first embodiment in that the actuation cam 20 locally has two flat areas 20c, 20d.

[0128] In this second mode, the two flat areas 20c, 20d are respectively arranged opposite the two parallel flat surfaces 32a of the receiving housing when the output shaft pivots respectively along the first additional angular sector a4 and the second additional angular sector a5. The two flat areas 20c, 20d are respectively distributed symmetrically with respect to the axis of symmetry 37 of the actuation profile.

[0129] As illustrated in [Fig.5], the interface component 20 is fixed rigidly to the output shaft 40.

[0130] The output shaft 40 mainly has a shape of revolution, including in particular a cylindrical bearing 44 which pivots in the protective housing 18 of the actuation device 10. The output shaft 40 also includes a toothed ring 45, here an external toothed ring which meshes with another gear of the speed reduction device 13.

[0131] We will now describe, with reference to [Fig. 6], a third embodiment of the invention, which differs from the first embodiment in that the interface component 20 is an eccentric actuating rod with respect to the second axis of rotation Y of the actuating device, the eccentric actuating rod being a cylindrical component which is inserted into the receiving housing 31 of the dog clutch sleeve 30. The rotation of the eccentric control rod 20 around the second axis of rotation Y of the speed reduction device 13 of the actuating device 10 allows the dog clutch sleeve 30 to be moved longitudinally.

[0132] In this third embodiment of the invention, the method for controlling the transmission shaft coupling system 1 comprises the following successive steps:

[0133] - rotate the output shaft 40 of the actuation device along a sector predetermined angular actuation has to axially move the dog clutch sleeve 30 from the first extreme uncoupling position to the second extreme coupling position;

[0134] - and then, rotate the output shaft 40 around a first angular sector additional a4, without axial displacement of the dog clutch sleeve, the direction of rotation being contrary to the direction of rotation of the predetermined angular sector of actuation a.

[0135] In this first embodiment of the control method, the angle value of the first additional angular sector a4 is 15° and the first additional angular sector a4 is adjacent to the predetermined actuation angular sector a. The angle value of the predetermined actuation angular sector a is 180°.

[0136] The direction of rotation of the first additional angular sector a4 is contrary to the direction of rotation of the predetermined angular actuation sector a, the output shaft of the actuation device returns angularly backwards with respect to the first step of the control process.

[0137] Thanks to the angular return of the output shaft 40 without displacement of the dog clutch sleeve 30, a functional clearance J2 is easily ensured between the interface component 20 and the receiving housing 31 of the dog clutch sleeve during the coupling operation of the transmission shafts. Heating at the contact point of the actuating cam is thus avoided.

[0138] We will now describe, with reference to [Fig.7], another embodiment which avoids heating at the point of contact between the interface component and the dog clutch sleeve after engaging the teeth.

[0139] In this embodiment, the transmission shaft coupling system comprises:

[0140] - a transmission shaft 2 comprising a first spline of transmission;

[0141] - a coaxial transmission shaft 3 leading shaft comprising a second transmission spline;

[0142] - a dog clutch sleeve 30 comprising at least one first groove of connection capable of driving the driving shaft in rotation along a first axis of rotation X and a second spline of connection capable of driving the driven shaft in rotation;

[0143] - an actuation device 10 comprising an output shaft 40 rotating around of a second rotation axis Y, an interface component 20 disposed at the end of the output shaft is arranged to pivot within a receiving housing 31 formed in the dog clutch sleeve 30, the dog clutch sleeve 30 being able to move axially along the first axis of rotation X between a first extreme disengagement position and a second extreme engagement position when the output shaft pivots along a predetermined angular sector of actuation a,

[0144] the receiving housing 31 is an annular groove comprising two parallel flat surfaces 32a,

[0145] wherein the interface component 20 is an eccentric actuating rod with respect to the second axis of rotation Y of the actuating device, the eccentric actuating rod being a roller bearing which is inserted into the receiving housing 31 of the dog clutch sleeve 30.

[0146] As illustrated in [Fig.7], the axis of rotation of the roller bearing is parallel and distant from the second axis of rotation Y.

[0147] The rotation of the outer ring 27 of the roller bearing on one of the two parallel flat surfaces 32a of the receiving housing 31 prevents heating at the point of contact. The rotation of the outer ring 27 of the roller bearing around the second axis of rotation Y of the actuating device 10 allows the dog clutch sleeve 30 to move longitudinally.

[0148] The inner ring 26 of the roller bearing is fixed relative to the output shaft 40, for example fixed using a rivet or a screw.

[0149] Alternatively, the eccentric actuating rod 20 can be a ball bearing.

[0150] The output shaft 40 mainly has a shape of revolution, including in particular a cylindrical bearing 44 which pivots in the protective housing of the actuation device 10. The output shaft 40 also includes a toothed ring 45, here an internal toothed ring which meshes with another gear of the speed reduction device 13.

[0151] The present invention is not limited to the means and configurations described and illustrated herein and also extends to any equivalent means and configuration as well as to any technically operative combination of such means.

Claims

Demands

1. A method for controlling a transmission shaft coupling system (1) comprising: - a driving transmission shaft (2) including a first transmission spline (2a); - a driven transmission shaft (3) coaxial with the driving shaft including a second transmission spline (3a); - a dog clutch sleeve (30) including at least a first connecting spline (33) adapted to drive the driving shaft (2) in rotation about a first axis of rotation (X) and a second connecting spline (34) adapted to drive the driven shaft (3) in rotation; - an actuation device (10) including an output shaft (40) rotating about a second axis of rotation (Y), an interface component (20) disposed at the end of the output shaft (40) and arranged to pivot within a receiving housing (31) formed in the dog clutch sleeve;the dog clutch sleeve (30) being able to move axially along the first axis of rotation (X) between a first extreme disengagement position and a second extreme engagement position when the output shaft pivots along a predetermined angular actuation sector (a), the control method having at least the following successive steps: - to rotate the output shaft (40) of the actuating device along the predetermined angular actuation sector (a) to move the dog clutch sleeve (30) axially from the first extreme disengagement position to the second extreme engagement position; - and then, to rotate the output shaft (40) along a first additional angular sector (a4) between 1° and 40°, for example between 5° and 15°, without axial displacement of the dog clutch sleeve, the direction of rotation being the same as or opposite to the direction of rotation of the predetermined angular actuation sector (a).

2. Control method according to claim 1, wherein the first additional angular sector (a4) is adjacent to the predetermined actuation angular sector (a).

3. Control method according to claim 1 or 2, wherein the predetermined angular sector of actuation (a) is between 20° and 180°.

4. A control method according to any one of claims 1 to 3, wherein the direction of rotation of the first additional angular sector (a4) is identical to the direction of rotation of the predetermined actuating angular sector (a), having the following two successive steps: - rotating the output shaft (40) of the actuating device, in the direction of rotation opposite to the first step of the control method, along the first additional angular sector (a4) and the predetermined actuating angular sector (a) to axially move the dog clutch sleeve (30) from the second extreme coupling position to the first extreme uncoupling position;- and then, rotate the output shaft (40) according to a second additional angular sector (a5) between 1° and 40°, for example between 5° and 15°, without axial displacement of the dog clutch sleeve, the direction of rotation being identical or opposite to the direction of rotation of the previous step.;

5. A control method according to any one of claims 1 to 3, wherein the direction of rotation of the first additional angular sector (a4) is contrary to the direction of rotation of the predetermined actuating angular sector (a), having the following two steps: - to rotate the output shaft (40) of the actuating device, in the direction of rotation contrary to the first step of the control method, according to the predetermined actuating angular sector (a) for which the value of the angle of the first additional angular sector (a4) has been subtracted to axially move the dog clutch sleeve (30) from the second extreme coupling position to the first extreme uncoupling position;- and then, rotate the output shaft according to a second additional angular sector (a5) between 1° and 40°, for example between 5° and 15°, without axial displacement of the dog clutch sleeve, the direction of rotation being identical or opposite to the direction of rotation of the previous step.;

6. A control method according to any one of the preceding claims, wherein the receiving housing (31) of the dog clutch sleeve is an annular groove comprising two parallel flat surfaces (32a).

7. A control method according to any one of claims 1 to 6, wherein the interface component (20) is an eccentric actuating rod with respect to the second axis of rotation (Y) of the actuating device, the eccentric actuating rod being a cylindrical component which is inserted into the receiving housing (31) of the dog clutch sleeve (30).

8. A control method according to any one of claims 1 to 6, wherein the interface component (20) is an actuating cam pivoting about the second axis of rotation (Y) of the actuating device which has in section perpendicular to the second axis of rotation (Y) a general Reuleaux triangle profile, the actuating cam being inserted into the receiving housing (31) of the dog clutch sleeve (30).

9. A control method according to claim 6, wherein the interface component (20) is an actuating cam (20) pivoting about the second axis of rotation (Y) and having two contact areas (20a, 20b) arranged to press against the parallel flat surfaces (32a) of the receiving housing (31), the first bearing width (L1) separating the two contact areas, measured along the first axis of rotation (X), is constant when the output shaft (40) pivots about the predetermined angular actuation sector (a) and the actuating cam (20) has a second width (L2) separating the two contact areas, measured along the first axis of rotation (X), less than the first bearing width (L1) when the output shaft (40) pivots about the additional angular sector (a4) adjacent to the predetermined angular actuation sector (a).

10. A drive shaft coupling system (1) comprising: - a drive shaft (2) including a first drive spline (2a); - a driven shaft (3) coaxial with the drive shaft including a second drive spline (3a); - a dog clutch sleeve (30) including at least one first connecting spline (33) capable of rotating the drive shaft (2) about a first axis of rotation (X) and a second a connecting spline (34) adapted to drive the driven shaft (3) in rotation; - an actuation device (10) comprising an output shaft (40) rotating about a second axis of rotation (Y), an interface component (20) disposed at the end of the output shaft (40) and arranged to pivot within a receiving housing (31) formed in the dog clutch sleeve, the dog clutch sleeve (30) being able to move axially along the first axis of rotation (X) between a first extreme disengagement position and a second extreme engagement position when the output shaft (40) pivots within a predetermined angular actuation sector (a), the receiving housing (31) is an annular groove comprising two parallel flat surfaces (32a), characterized in that the interface component (20) is an actuating cam pivoting about the second axis of rotation (Y) and having two contact areas (20a,20b) arranged to bear on the parallel flat surfaces (32a) of the receiving housing (31), the first bearing width (L1) separating the two contact areas, measured along the first axis of rotation (X), is constant when the output shaft (40) pivots about the predetermined angular actuation sector (a) and the actuating cam has a second width (L2) separating the two contact areas, measured along the first axis of rotation (X), less than the first bearing width (L1) when the output shaft (40) pivots about a first additional angular sector (a4) adjacent to the predetermined angular actuation sector (a).

11. A transmission shaft coupling system (1) according to the preceding claim, wherein the actuating cam (20) has, in cross-section perpendicular to the second axis of rotation (Y), a general Reuleaux triangle profile, the first bearing width (L1) separating the two contact zones (20a, 20b) of which remains constant over the entire predetermined angular actuation sector (a), and the profile of the actuating cam locally has at least one flat or concave zone (20c, 20d), the at least one flat or concave zone (20c, 20d) being disposed opposite one of the two parallel flat surfaces of the receiving housing when the output shaft pivots according to the first additional angular sector (a4).

12. Transmission shaft coupling system (1) according to claim 10 or 11, wherein the predetermined angular actuation sector (a) consists of three adjacent angular sub-sectors (a1, a2, a3), a first angular sub-sector (a1), a second angular sub-sector (a2) which is adjacent to the first angular sub-sector, a third angular sub-sector (a3) ​​which is adjacent to the second angular actuation sub-sector, and wherein the dog clutch sleeve (30) moves axially between two extreme positions when the output shaft pivots through the entire second angular sub-sector (a2), the dog clutch sleeve (30) remaining axially stationary in the first extreme position when the rotation of the output shaft is within the first angular sub-sector (a1),and the dog clutch sleeve (30) remaining axially immobile in the second extreme position when the rotation of the output shaft is in the third angular sub-sector (a3).

13. Transmission shaft coupling system (1) according to any one of claims 10 to 12, wherein the dog clutch sleeve (30) comprises at least one first internal connecting spline (33) arranged to drive the driving shaft (2) in rotation and a second internal connecting spline (34) arranged to drive the driven shaft (3) in rotation, the first and second internal connecting splines (33, 34) being engaged respectively in a first external transmission spline (2a) of the driving shaft and a second external transmission spline (3a) of the driven shaft when the dog clutch sleeve (30) is in the second extreme coupling position.

14. A transmission shaft coupling system (10) according to any one of claims 10 to 13, wherein an operating clearance (J1, J2) is defined between the bearing width (L1, L2) of the actuating cam and the distance (D) separating the two parallel flat surfaces (32a) of the receiving housing (31), a first operating clearance (J1) being constant when the output shaft (40) pivots through the predetermined angular actuation sector (a) and a second operating clearance (J2) being greater than the first clearance

15. of operation (Jl) when the output shaft (40) pivots according to the first additional angular sector (a4). Transmission shaft coupling system (10) according to the preceding claim, wherein the second operating clearance (J2) comprises the sum of the first operating clearance (J1) and an additional clearance (J3), such that J2 = J1 + J3, for example J2 = J1 + 0.5 mm.

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