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

Abstract

The present invention relates to a transmission shaft coupling system (1) comprising: - a drive shaft; - a driven shaft coaxial with the drive shaft; - a dog-clutch sleeve (30) arranged to move along a first axis of rotation (X) to couple the drive shaft to the driven shaft; - an actuating device (10) comprising an output shaft (40) rotating about a second axis of rotation (Y), and one end of the output shaft is 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 decoupling end position and a second coupling end position when the output shaft pivots in accordance with a predetermined actuation angular sector (α), in which a rolling bearing (20) is attached to the end of the output shaft eccentrically and is inserted into the receiving housing of the dog-clutch sleeve (30).

Description

[0001] DESCRIPTION

[0002] Title: Transmission shaft coupling system and method for controlling such a transmission shaft coupling system 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.

[0003] The driveshaft coupling system is, for example, integrated into the electric transmission of a motor vehicle, which includes an electric motor and an associated speed reducer. The coupling system is positioned, in particular, between the output of the speed reducer and the vehicle wheel. The motor vehicle may be electric or hybrid.

[0004] In a hybrid motor vehicle 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

[0005] 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.

[0006] The coupling system also includes a double-grooved dog clutch sleeve for connecting the driving shaft to the driven shaft when electric transmission is required. 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 coupled to a speed reduction device, for example, a planetary gear train.

[0007] For this purpose, an internal surface of the dog clutch sleeve is provided with an internal groove that mates with the external groove of the driven transmission shaft and an external groove that is able to mate with the internal groove of the driving transmission shaft.

[0008] When the coupling system is in the uncoupled position, the outer spline of the connector is not engaged in the first inner spline of the driving shaft. The driving shaft and the connector rotate at different speeds. 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 planetary gear train moves the dog clutch sleeve longitudinally.

[0009] When the coupling system is in the engaged 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. It is therefore understandable that if the contact pressure between the eccentric control rod and the groove of the dog clutch sleeve remains present during the engagement phase, heating at the contact point can occur and generate wear, especially if this contact pressure is maintained for a long period. The present invention aims to overcome these drawbacks by providing a transmission shaft coupling system in which heating at the contact point is reduced, or even eliminated, between the interface component of the actuation device and the dog clutch sleeve.

[0010] To achieve this, according to a first aspect of the invention, a transmission shaft coupling system is proposed, comprising:

[0011] - a drive shaft comprising a first transmission spline;

[0012] - a coaxial transmission shaft to the driving shaft comprising a second transmission spline;

[0013] - a dog clutch sleeve comprising at least one first connecting spline suitable for rotating the driving shaft about a first axis of rotation X and a second connecting spline suitable for rotating the driven shaft; - an actuating device comprising an output shaft rotating about a second axis of rotation Y, an actuating rod disposed eccentrically with respect to the second axis of rotation Y at the end of the output shaft and arranged to pivot within a receiving housing formed in the dog clutch sleeve, the receiving housing being an annular groove comprising a bottom and two lateral rims,

[0014] the dog clutch sleeve can 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 within a predetermined angular actuation sector oc,

[0015] in which a roller bearing is attached to the actuating rod and inserted into the receiving housing of the dog clutch sleeve.

[0016] In this first aspect of the invention, the roller bearing forms the interface component between the actuation device and the dog clutch sleeve.

[0017] For example, the bearing can be a ball bearing, a roller bearing, or a needle bearing.

[0018] This driveshaft coupling system prevents overheating at the contact point between the interface component and the dog clutch sleeve after the gears have engaged. Despite the relative rotational speed between the interface component and the dog clutch sleeve, the presence of rolling elements such as balls, rollers, or needles reduces wear at the contact point.

[0019] Compared to the document cited previously, the sliding between the eccentric control rod and the groove of the dog clutch sleeve is replaced by a ball bearing or roller bearing at the interface of the actuation device and the dog clutch sleeve.

[0020] Preferably, the bearing unit comprises an inner ring held in position on the actuating rod, an outer ring bearing against the receiving housing, and bearing elements interposed between the inner and outer rings. According to one embodiment of the invention, the actuating device may comprise an electric motor kinematically linked to a speed reduction device, said speed reduction device comprising the output shaft which rotates about the second axis of rotation Y, the bearing unit being arranged eccentrically with respect to the second axis of rotation Y at the end of the output shaft. For example, the speed reduction device comprises an epicyclic gear train or parallel shaft gears.

[0021] According to one embodiment of the invention, the two lateral edges of the receiving housing are two parallel flat surfaces.

[0022] According to another embodiment of the invention, the two lateral edges of the receiving housing are two frustoconical surfaces.

[0023] According to another embodiment of the invention, the two lateral edges of the receiving housing are two convex surfaces.

[0024] According to one embodiment of the invention, the outer diameter of the outer ring of the roller bearing is constant. The roller bearing has a generally cylindrical shape.

[0025] The outer diameter of the outer ring. According to another embodiment of the invention, the bearing housing is variable along its axis of revolution. For example, in section along a plane passing through the axis of rotation, the outer ring has a convex profile.

[0026] According to one example, the rolling bearing has a general partially hemispherical shape.

[0027] As an example, the rolling bearing has a general barrel shape.

[0028] As an example, the rolling bearing has a general toroidal shape.

[0029] In one example, the rolling bearing has a generally frustoconical shape. According to one embodiment of the invention, a first operating clearance J1 is defined between the outer diameter of the outer ring of the rolling bearing and the distance separating the two lateral edges of the receiving housing. This first operating clearance J1 is constant when the output shaft pivots through the predetermined angular sector of actuation. The first operating clearance J1 is constant whether the general shape of the rolling bearing is cylindrical, hemispherical, or frustoconical. In the case where the general shape of the rolling bearing is hemispherical, the first operating clearance J1 is constant, taking into account the maximum outer diameter of the outer ring.

[0030] According to one embodiment of the invention, the bearing is in contact with one of the lateral edges of the receiving housing, which also has a frustoconical surface. The contact line between the bearing and the lateral edge follows the following combination of radii: R4 = R3 x r2 / r1, where

[0031] rl = outer radius of contact at the receiving housing level;

[0032] r2 = inner radius of contact at the level of the receiving housing;

[0033] R3 = upper radius of contact at the level of the bearing;

[0034] R4 = lower radius of contact at the bearing level.

[0035] In this way, the calculated or measured rotational speed at the contact line between the bearing and the receiving housing is identical at all points along this line. Thanks to this combination of radii, the smooth rolling of the interface component between the actuation device and the clutch sleeve is guaranteed, and the risk of slippage at the interface is eliminated.

[0036] According to one embodiment of the invention, the inner ring of the bearing is fixed to the actuating rod by riveting or crimping, for example by orbital crimping.

[0037] According to one variant of the invention, the dog clutch sleeve comprises at least one first internal 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 external 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.

[0038] According to another variant 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.

[0039] As previously mentioned, the present invention aims to reduce wear at the contact point between the interface component and the dog clutch sleeve after the teeth have engaged. To this end, a method for controlling a transmission shaft coupling system is proposed, incorporating all or part of the characteristics mentioned above.

[0040] the control process comprising at least the following successive steps:

[0041] - rotate the output shaft of the actuation device according to the predetermined angular actuation sector to axially move the dog clutch sleeve from the first extreme disengagement position to the second extreme coupling position;

[0042] - and then, rotate the output shaft according to a first additional angular sector 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.

[0043] 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 overheating 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.

[0044] 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 as soon as the first step of the control method is completed.

[0045] If the direction of rotation of the first additional angular sector is the same as the direction of rotation of the predetermined actuating angular sector, the output shaft of the actuator pivots beyond the predetermined actuating angular sector and thus achieves a greater angular deflection. If the direction of rotation of the first additional angular sector is opposite to the direction of rotation of the predetermined actuating angular sector, the output shaft of the actuator returns angularly to the position of the first step in the control process.

[0046] Preferably, the first additional angular sector is adjacent to the predetermined actuation angular sector.

[0047] Preferably, the predetermined angular actuation sector is between 20° and 180°.

[0048] The invention also relates, according to another aspect of the invention, to a motor vehicle with hybrid or electric transmission comprising a transmission shaft coupling system as previously mentioned.

[0049] 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 attached drawings on the other hand, in which:

[0050] [Fig. 1] is a cross-sectional view of a transmission shaft coupling system according to a first embodiment of the invention;

[0051] [Fig. 2] is a simplified view of the coupling system of figure 1 in one of the extreme positions according to the first embodiment of the invention;

[0052] [Fig. 3] is a simplified view of the interface end of the output shaft of the actuation device in Figure 1;

[0053] [Fig. 4] is another simplified view of the interface end of the output shaft of the actuation device having pivoted along the first additional angular sector œ4;

[0054] [Fig. 5] is a cross-sectional view of the output shaft of the transmission shaft coupling system according to a second embodiment of the invention;

[0055] [Fig. 6] is a cross-sectional view of the output shaft of the transmission shaft coupling system according to a third embodiment of the invention.

[0056] [Fig. 7] is a cross-sectional view of the output shaft of the transmission shaft coupling system according to a fourth embodiment of the invention.

[0057] Figure 8 is a cross-sectional view of the output shaft of the driveshaft coupling system according to a fifth embodiment of the invention. The features, variations, and different embodiments of the invention can be combined in various ways, provided they are not incompatible or mutually exclusive. Throughout this description, elements common to several figures retain the same reference numeral.

[0058] In the description and claims, the terms "external" and "internal," as well as the orientations "axial" and "radial," will 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 that determines the "axial" orientation. From the inside out, away from said axis, the "circumferential" orientation is directed orthogonally to the first axis of rotation X and orthogonally to the radial direction. Figures 1 to 4 illustrate a transmission shaft coupling system 1 according to a first embodiment of the invention. The operation of a transmission shaft coupling system will be described in general terms.

[0059] The driveshaft coupling system 1 is a connecting clutch between two shafts 2 and 3, used in a vehicle's drivetrain to transmit torque from a combustion 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 motor of the vehicle, 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 a combustion engine, to the wheel shafts of another axle of the vehicle. 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.

[0060] The transmission shaft coupling system 1 is kinematically interposed between a speed reducer and the vehicle's wheel shaft 7. The output of the speed reducer is rotationally fixed to a drive shaft 2 about a first axis of rotation X. The drive shaft 2 has a first transmission spline 2a machined on its end; in this example, the first transmission spline is external.

[0061] The driveshaft coupling system 1 also includes a driven 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 a guide bearing 4 around the first axis of rotation X. The driven shaft 3 also includes an internal torque output spline 3b rotationally connected to the vehicle's wheel shaft 7.

[0062] The drive shaft coupling system 1 uses a dog clutch sleeve 30 to connect the two drive 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 rotate the drive shaft 2 and a second connecting spline 34 adapted to rotate the driven shaft 3. 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. To actuate the drive shaft coupling system 1, an electrically powered actuator 10 is used.The actuation 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, an actuating rod 50 eccentric with respect to the second axis of rotation Y which is disposed at the end of the output shaft, and a roller bearing 20, disposed at the end of the output shaft which interacts with the dog clutch sleeve 30. The roller bearing 20 is an interface component arranged to pivot within a receiving housing 31 formed directly in the dog clutch sleeve 30. The receiving housing 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.

[0063] As illustrated in Figure 1, the bearing 20 is fixed rigidly to the output shaft 40.

[0064] The bearing 20 comprises an inner ring 26 held in position on the eccentric actuating rod 50, an outer ring 27 bearing on the receiving housing and bearing elements 28 interposed between the inner ring and the outer ring.

[0065] The output shaft 40 is primarily rotary, notably featuring 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. In this first embodiment of the invention, the speed reduction device 13 comprises a spur gear train. The toothed ring 45 of the output shaft participates in the final speed reduction stage of the electric motor 11.

[0066] 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 mounted on 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.

[0067] As illustrated in Figure 4, the dog clutch sleeve 30 moves axially between two extreme positions of disengagement and engagement when the output shaft 40 pivots about its second axis of rotation Y through a predetermined angular sector. The dog clutch sleeve 30 moves axially by a distance of between 5 and 50 mm relative to the driven transmission shaft 3, which is axially fixed. 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 segmented to reduce the engagement stroke.

[0068] 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.

[0069] The receiving housing 31 of the dog clutch sleeve 30 has two lateral flanges 32a and receives the roller bearing 20 of the actuating device, which forms the interface component between the actuating device and the dog clutch sleeve. In this first embodiment, the actuating rod 50 is arranged eccentrically with respect to the second axis of rotation Y at the end of the output shaft and configured to pivot within a receiving housing.

[0070] As illustrated in Figure 2, the actuator rod 50 is eccentric with respect to the second axis of rotation Y according to an eccentricity value E between 3 and 15 mm.

[0071] The actuating rod 50 supports the bearing 20. The rotation of the actuating rod 50 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.

[0072] In this case, the interface component is implemented in the form of a ball bearing 20 which has a generally cylindrical shape. The two lateral edges 32a are, in this first embodiment, two parallel flat surfaces formed from the material of the clutch sleeve.

[0073] To ensure a free movement of the bearing 20 within the annular groove without undue friction, a first operating clearance J1 is defined between the outer diameter Dext of the ball bearing 20 and the distance L separating axially along the first axis of rotation X the two parallel flat surfaces 32a of the receiving housing 31. In this case, the outer diameter Dext of the ball bearing 20 is constant.

[0074] In order to recenter the bearing housing 20 in the receiving housing 31, the first axis of rotation X of the dog clutch sleeve 30 may not intersect the second axis of rotation Y. For example, the second axis of rotation Y may be offset from 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.

[0075] We will now describe the operation of the actuation device which allows the transition from the first extreme uncoupling position to the second extreme coupling position with a reduced actuation time.

[0076] As illustrated in Figure 3, the output shaft 40 is arranged to pivot within a predetermined angular sector of actuation oc. The control method for the transmission shaft coupling system 1 comprises the following successive steps:

[0077] - rotate the output shaft 40 of the actuation device according to a predetermined angular actuation sector œ to axially move the dog clutch sleeve 30 from the first extreme disengagement position to the second extreme coupling position;

[0078] - and then, rotate the output shaft 40 along a first additional angular sector oc4, without axial displacement of the dog clutch sleeve, the direction of rotation being opposite to the direction of rotation of the predetermined actuating angular sector oc. In this embodiment of the control method, the angle value of the first additional angular sector o4 is 15° and the first additional angular sector o4 is adjacent to the predetermined actuating angular sector oc. The angle value of the predetermined actuating angular sector oc is 180°.

[0079] The direction of rotation of the first additional angular sector oc4 is contrary to the direction of rotation of the predetermined actuation angular sector oc, therefore the output shaft of the actuation device returns angularly backwards relative to the first step of the control process.

[0080] Thanks to the angular return of the output shaft 40 without displacement of the dog clutch sleeve 30, a second functional clearance J2 is ensured which is less than the first functional clearance JL

[0081] The second functional clearance J2 between the bearing 20 and the receiving housing 31 of the dog clutch sleeve in the operating phase of coupling the transmission shafts prevents contact of the outer ring with the dog clutch sleeve.

[0082] We will now describe, with reference to Figure 5, a second embodiment of the invention which makes it possible to avoid heating at the point of contact between the interface component of the actuation device and the dog clutch sleeve after engaging the teeth.

[0083] In this second embodiment, the transmission shaft coupling system comprises: - a transmission drive shaft 2 comprising a first transmission spline;

[0084] - a driven shaft 3 coaxial transmission shaft to the driving shaft comprising a second transmission spline;

[0085] - a dog clutch sleeve 30 comprising at least one first connecting spline suitable for rotating the driving shaft about a first axis of rotation X and a second connecting spline suitable for rotating the driven shaft; - an actuation device 10 comprising an output shaft 40 rotating about a second axis of rotation Y, a roller bearing 20 disposed at the end of the output shaft and 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 about the first axis of rotation X between a first extreme disengagement position and a second extreme engagement position when the output shaft pivots about a predetermined angular sector of actuation oc,

[0086] the receiving housing 31 is an annular groove comprising two parallel flat surfaces 32a,

[0087] in which the bearing housing 20 is a roller bearing which is inserted into the receiving housing 31 of the dog clutch sleeve 30.

[0088] The roller bearing 20 comprises an inner ring 26 held in position on the actuating rod 50, an outer ring 27 bearing against the receiving housing, and bearing elements 28 interposed between the inner and outer rings. As illustrated in Figure 5, the axis of rotation of the roller bearing is parallel to and at a distance from the second axis of rotation Y.

[0089] 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 contact point. 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.

[0090] The inner ring 26 of the roller bearing is fixed relative to the output shaft 40, for example fixed with a rivet or a screw.

[0091] Alternatively, the bearing housing 20 can be a needle bearing. The output shaft 40 is primarily a rotary shape, including a cylindrical bearing surface 44 that pivots within the protective housing of the actuation device 10. The output shaft 40 also includes a toothed ring 45, in this case an internal toothed ring that meshes with another gear of the speed reduction device 13.

[0092] We will now describe, with reference to figure 6, a third embodiment of the invention which makes it possible to avoid heating at the point of contact between the interface component of the actuation device and the dog clutch sleeve after engaging the teeth.

[0093] In this third embodiment, the bearing 20 is a needle or roller bearing which is inserted into the receiving housing 31 of the dog clutch sleeve 30. The two lateral edges 32a of the receiving housing 31 are two parallel flat surfaces 32a.

[0094] The outer diameter Dext of the outer ring varies along its axis of revolution. In cross-section along a plane passing through the axis of rotation, the outer ring has a convex profile. Thus, the bearing housing 20 has a general barrel shape.

[0095] In this example, a first operating clearance J1 is defined between the outer diameter of the outer ring of the bearing and the distance between the two lateral edges of the receiving housing. This first operating clearance J1 remains constant when the output shaft pivots through the predetermined angular sector of actuation. The first operating clearance J1 is constant even when considering the maximum outer diameter of the outer ring.

[0096] We will now describe, with reference to figure 7, a fourth embodiment of the invention which makes it possible to avoid heating at the point of contact between the interface component of the actuation device and the dog clutch sleeve after engaging the teeth.

[0097] In this fourth embodiment, the bearing housing 20 is a ball bearing inserted into the receiving housing 31 of the clutch sleeve 30. The two lateral edges 32 of the receiving housing 31 are two frustoconical surfaces 32b. The bearing housing 20 comprises an inner ring 26 held in position on the actuating rod 50, an outer ring 27 bearing against the receiving housing, and bearing elements 28 interposed between the inner and outer rings. As illustrated in Figure 7, the axis of rotation of the ball bearing is parallel to and at a distance from the second axis of rotation Y.

[0098] The rotation of the outer ring 27 of the ball bearing on one of the two frustoconical surfaces 32b of the receiving housing 31 prevents heating at the contact point. The rotation of the outer ring 27 of the ball bearing allows the dog clutch sleeve 30 to move longitudinally.

[0099] The inner ring 26 of the ball bearing is fixed relative to the output shaft 40, for example fixed with a rivet or a screw.

[0100] In this embodiment, the actuating rod 50 comprises one end embedded in the output shaft and another free end, the outside diameter Dext of the bearing 20 is variable along its axis of revolution between a first diameter and a second diameter, the second diameter located near the free end of the actuating rod being smaller than the first diameter located near the embedded end of the actuating rod.

[0101] The bearing housing 20 has a generally frustoconical shape on its outer casing. This bearing housing is in contact with one of the lateral edges 32 of the receiving housing, which also has a frustoconical surface 32b. The contact line between the bearing housing and the lateral edge follows the following combination of radii: R4 = R3 x r2 / r1, where

[0102] rl = outer radius of contact at the level of the receiving housing 31;

[0103] r2 = inner radius of contact at the level of the receiving housing 31;

[0104] R3 = upper radius of contact at the bearing level 20;

[0105] R4 = lower radius of contact at the bearing level 20.

[0106] This radius configuration ensures that the rotational speed present at the contact line between the bearing 20 and the receiving housing 31 is identical at all points constituting this line.

[0107] The inner and outer radii rl and r2 relate to the first axis of rotation X. The lower and upper radii R3 and R4 relate to the axis of revolution of the actuating rod 50.

[0108] In this example where the general shape of the bearing 20 is frustoconical, a first operating clearance J1 is defined between the outer diameter of the outer ring 27 of the bearing and the distance separating the two lateral edges of the receiving housing, the first operating clearance J1 being constant when the output shaft pivots according to the predetermined angular sector of actuation.

[0109] We will now describe, with reference to figure 8, a fifth embodiment of the invention which differs from the first embodiment in that the two lateral edges of the receiving housing 31 are not flat.

[0110] The bearing housing 20 comprises an inner ring 26 held in position on the actuating rod 50, an outer ring 27 bearing against the receiving housing, and bearing elements 28 interposed between the inner and outer rings. The outer diameter of the outer ring 27 of the bearing housing 20 is constant. The bearing housing 20 has a generally cylindrical shape.

[0111] In this fifth embodiment, the bearing housing 20 is a ball bearing that is inserted into the receiving housing 31 of the dog clutch sleeve 30. The two lateral edges 32 of the receiving housing 31 are two convex surfaces 32c. The contact between the outer ring 27 of the bearing housing and the receiving housing 31 is circular.

[0112] 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 any technically operative combination of such means.

Claims

DEMANDS 1. Transmission shaft coupling system (1) comprising: - a transmission drive shaft (2) comprising a first transmission spline (2a); - a driven shaft (3) coaxial to the driving shaft comprising a second transmission spline (3a); - a dog clutch sleeve (30) comprising at least a first connecting groove (33) suitable for driving the driving shaft (2) in rotation about a first axis of rotation (X) and a second connecting groove (34) suitable for driving the driven shaft (3) in rotation; - an actuation device (10) comprising an output shaft (40) rotating about a second axis of rotation (Y), an actuating rod (50) disposed eccentrically with respect to the second axis of rotation (Y) at the end of the output shaft and arranged to pivot within a receiving housing (31) formed in the dog clutch sleeve, the receiving housing (31) being an annular groove comprising a bottom and two lateral rims (32), 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), characterized in that a bearing (20) is attached to the actuating rod (50) and inserted into the receiving housing of the dog clutch sleeve (30).

2. Transmission shaft coupling system (1) according to the preceding claim, wherein the bearing support (20) is a ball bearing or a roller bearing.

3. Transmission shaft coupling system (1) according to the preceding claim, in which the bearing comprises an inner ring (26) held in position on the actuating rod (50), an outer ring (27) bearing on the receiving housing and bearing elements (28) interposed between the inner ring and the outer ring.

4. Transmission shaft coupling system (1) according to the preceding claim, in which the outside diameter (Dext) of the outer ring (27) of the bearing (20) is constant, for example the bearing has a general cylindrical shape.

5. Transmission shaft coupling system (1) according to any one of the preceding claims, wherein the two lateral edges (32) of the receiving housing (31) are two parallel flat surfaces (32a).

6. Transmission shaft coupling system (1) according to claim 1 to 3, wherein the outside diameter (Dext) of the outer ring (27) of the bearing (20) is variable along its axis of revolution.

7. Transmission shaft coupling system (1) according to the preceding claim, in which the rolling bearing (20) has a generally partially hemispherical or toroidal shape.

8. Transmission shaft coupling system (1) according to the preceding claim, wherein the two lateral edges (32) of the receiving housing (31) are two parallel flat surfaces (32a).

9. Transmission shaft coupling system (1) according to claim 6, wherein the bearing housing (20) has a generally frustoconical shape.

10. Transmission shaft coupling system (1) according to the preceding claim, wherein the two lateral edges (32) of the receiving housing are two frustoconical surfaces (32b).

11. Transmission shaft coupling system (1) according to any one of the preceding claims, wherein a first operating clearance J1 is defined between the outside diameter (Dext) of the outer ring (26) of the bearing housing and the distance separating the two lateral edges (32) of the receiving housing, the first operating clearance J1 being constant when the output shaft (40) pivots according to the predetermined angular sector of actuation.

12. A drive shaft coupling system (1) according to any one of the preceding claims, wherein the actuation device (10) comprises an electric motor (11) kinematically linked to a speed reduction device (13), said speed reduction device comprising the output shaft (40) which rotates around the second axis of rotation (Y), the bearing support (20) being arranged eccentrically with respect to the second axis of rotation (Y) at the end of the output shaft (40).

13. Transmission shaft coupling system (1) according to any one of the preceding claims, 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. Transmission shaft coupling system (1) according to claim 1, wherein the bearing housing (20) is a needle bearing.

15. A method for controlling a transmission shaft coupling system (1) comprising a transmission shaft coupling system (1) according to any one of the preceding claims, the control process comprising at least the following successive steps: - rotate the output shaft (40) of the actuation device according to the predetermined angular actuation sector (a) to axially move the dog clutch sleeve (30) from the first extreme disengagement position to the second extreme coupling position; - and then, rotate the output shaft (40) according to a first additional angular sector (oc4) 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 contrary to the direction of rotation of the predetermined angular sector of actuation (a).

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