System for coupling transmission shafts and transmission comprising such a system for coupling transmission shafts

Abstract

The present invention relates to a system for coupling transmission shafts (1), the system comprising: - a drive shaft; - a driven shaft coaxial with the drive shaft; - a dog clutch sleeve (30) arranged so as to move along a first axis of rotation (X) in order to couple the drive shaft to the driven shaft; - a casing (50) surrounding the drive shaft and the driven shaft, which comprises a casing end (61) through which the drive shaft passes; - an actuating device (10) comprising an interface component (20) inserted into a receiving cavity (31) formed in the dog clutch sleeve, the interface component being arranged so as to axially move the dog clutch sleeve (30) between a first uncoupling end position and a second coupling end position, wherein the casing end (60) comprises a lubricating fluid collecting portion (61) and a lubricating fluid retaining portion (62) distributed about the first axis of rotation (X).

Description

[0001] DESCRIPTION

[0002] Title: Driveshaft coupling system and transmission comprising such a driveshaft coupling system

[0003] The present invention relates to the field of transmission shaft coupling systems and transmissions comprising such a transmission shaft coupling system.

[0004] 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.

[0005] 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

[0006] 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.

[0007] 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 a first 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.

[0008] 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.

[0009] 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.

[0010] When the coupling system is in the engaged position, the rotational speeds of the driven shaft, the driving shaft, and the clutch sleeve are identical, while the eccentric control rod is fixed in rotation relative to the first axis of rotation. Therefore, there is a relative velocity between the interface component of the actuation device defined by the eccentric control rod and the clutch sleeve.

[0011] 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.

[0012] 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.

[0013] To achieve this, according to a first aspect of the invention, a transmission shaft coupling system is proposed, comprising:

[0014] - a drive shaft comprising a first transmission spline;

[0015] - a coaxial driven transmission shaft to the driving shaft comprising a second transmission spline; - a dog clutch sleeve comprising at least a first connection spline suitable for driving the driving shaft in rotation about a first axis of rotation and a second connection spline suitable for driving the driven shaft in rotation;

[0016] - a coupling system housing being suitable for containing lubricating fluid and having a general shape of revolution surrounding the driving shaft, the driven shaft and the dog clutch sleeve along the first axis of rotation, said housing comprising a housing body and a housing end through which the driving shaft passes;

[0017] - an actuation device supported by the housing comprising an interface component inserted within a receiving housing formed in the dog clutch sleeve, the interface component being arranged to axially move the dog clutch sleeve inside the housing along the first axis of rotation between a first extreme disengagement position and a second extreme coupling position, wherein the end of the housing has an asymmetrical profile with respect to the first axis of rotation and comprises a lubrication fluid collection portion and a lubrication fluid retention portion distributed around the first axis of rotation.

[0018] This driveshaft coupling system keeps the contact between the interface component and the clutch sleeve within the vehicle's driveshaft coupling system lubricated. Overheating at the contact point is thus prevented by retaining a certain amount of lubricating fluid inside the coupling system housing.

[0019] The introduction of the lubricating fluid into the driveshaft coupling system is ensured simply via the collection port at the end of the housing. The lubricating fluid retention port maintains the collected quantity of fluid regardless of the vehicle's angle of inclination or any lateral acceleration that might otherwise cause the fluid to be expelled from the housing.

[0020] Advantageously, the housing end includes a sealing wall extending radially with respect to the first axis of rotation, for example, perpendicularly, and a through-hole for the driving shaft. The edge of the through-hole and the sealing wall together form the lubricating fluid retention area. For example, the sealing wall may extend to the through-hole. Alternatively, the sealing wall may extend beyond the through-hole so that the through-hole forms a bore. This allows the lubricating fluid level within the housing to be adjusted to ensure lubrication of the contact point and splines while controlling the drag torque within the drive shaft coupling system.

[0021] Preferably, the end of the housing includes at least one opening that leads to an external cylindrical wall of the housing to form the lubrication fluid collection area. The opening is oriented towards an area where lubrication fluid is available, such as inside the transmission of the motor vehicle.

[0022] For example, at least one opening is oblong in shape. The oblong opening can be oriented perpendicular to the first axis of rotation or parallel to the first axis of rotation.

[0023] Advantageously, at least one opening leads to both the outer cylindrical wall of the housing and the housing's closing wall. This increases the lubricating fluid collection capacity. For example, the opening can be machined. It is also possible to orient the opening relative to the housing body during the housing manufacturing process, depending on the vehicle application. The angular orientation of the opening is thus independent of the actuating device's position on the housing. Using standardized components, it is therefore possible to provide a coupling system adapted to the available space constraints within the vehicle manufacturer's transmission.

[0024] Preferably, the lubrication fluid collection portion and the lubrication fluid retention portion of the housing end are formed from the same material as the housing body. In this example, the housing body and the housing end are a single piece that forms the housing to reduce manufacturing costs and facilitate the assembly of the driveshaft coupling system.

[0025] Advantageously, the end of the housing includes at least one series of openings distributed around the first axis of rotation in an angular sector between 90° and 180°, the series of openings being located opposite the lubricating fluid retention area with respect to the first axis of rotation. The series of openings is oriented towards an area where lubricating fluid is available, such as within the transmission of the motor vehicle. In this example, the series of openings is made by radial drilling on the outer periphery of the housing to reduce the manufacturing costs of the driveshaft coupling system.

[0026] According to one aspect of the invention, the actuation device comprises an output shaft supporting the interface component, the output shaft passes through the coupling system housing at a secondary passage orifice, the secondary passage orifice of the output shaft of the actuation device being disposed opposite the lubrication fluid collection part with respect to the first axis of rotation.

[0027] Preferably, the secondary passage orifice of the output shaft is arranged opposite the lubricating fluid collection part relative to the first axis of rotation at an angle between 120° and 240°, for example 180°.

[0028] According to one aspect of the invention, the housing end, comprising the lubrication fluid collection portion and the lubrication fluid retention portion, is an additional component attached to the housing body to form the housing for the actuation system. The housing end is inserted into a central bore of the housing body. Thus, the housing body and the housing end are two separate parts that together form the housing, simplifying its overall shape. The housing end can also be oriented relative to the housing body during assembly, depending on the vehicle application. The angular orientation of the housing end is therefore independent of the actuation device's position on the housing. This allows for the provision of a coupling system adapted to the space constraints available within the vehicle manufacturer's transmission, using standardized components.

[0029] Advantageously, the end of the housing, produced as an additional component, is obtained by molding plastic or aluminum material or by stamping a sheet metal.

[0030] Preferably, the housing end includes a cylindrical centering rim arranged to be inserted into the central bore of the housing body along the first axis of rotation. This facilitates the assembly of the drive shaft coupling system. Advantageously, the housing end includes a through-hole for the drive shaft and an internal cylindrical rim extending along the first axis of rotation from the edge of the through-hole towards the actuating device.

[0031] Preferably, the housing body includes a longitudinal lubrication fluid flow groove formed on the inner wall of its central bore. For example, the longitudinal flow groove is formed directly from a casting. This longitudinal groove facilitates the flow of lubrication fluid from the end of the housing to the receiving housing of the dog clutch sleeve.

[0032] According to one aspect of the invention, the end of the housing includes a sealing gasket that rubs against the outer periphery of the drive shaft. This allows for the retention of even more lubricating fluid within the driveshaft coupling system, regardless of the vehicle's inclination or the lateral acceleration experienced by the vehicle, which could otherwise eject the lubricating fluid from the housing.

[0033] According to one aspect of the invention, the actuation device comprises an output shaft rotating about a second axis of rotation, the interface component being disposed at the end of the output shaft and arranged to pivot within the receiving housing formed in the dog clutch sleeve, the dog clutch sleeve being able to move axially inside the housing along the first axis of rotation between a first extreme disengagement position and a second extreme coupling position when the output shaft pivots along a predetermined angular sector of actuation.

[0034] Preferably, the predetermined angular actuation sector is between 20° and 180°.

[0035] The interface component of the actuation device is, for example, an actuation cam or an eccentric actuation rod.

[0036] According to one aspect of the invention, the interface component of the actuation device is an actuating cam pivoting about the second axis of rotation of the actuation device. 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 actuating cam has two contact areas arranged to bear against lateral edges of the receiving housing. The geometry of the contact areas of the actuating cam uses large-diameter cylindrical segments, thereby reducing the contact pressure with the clutch sleeve.

[0037] For example, the principal vertex of the isosceles triangle can be confused with the second axis of rotation of the output shaft.

[0038] Preferably, the actuating cam has 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.

[0039] 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 of the dog clutch sleeve.

[0040] The eccentric actuating rod can be a plain bearing or a rolling bearing, such as a ball bearing or a roller bearing. This allows for a free-rotating part around the eccentric axis, for example, the outer ring of the ball bearing, ensuring non-slip contact with the clutch sleeve, although lubrication of the contact with the eccentric shaft is still required. In this way, heat generation at the contact point is reduced between the interface component of the actuating device and the clutch sleeve. The rotation of the outer ring of the ball or roller bearing on one of the two parallel flat surfaces of the receiving housing limits heat generation at the contact point.

[0041] According to one aspect of the invention, the actuation device comprises an actuation fork, the interface component being disposed at one end of the actuation fork, the dog clutch sleeve being able to move axially inside the housing along the first axis of rotation between a first extreme disengagement position and a second extreme coupling position when the end of the actuation fork moves axially according to a predetermined value.

[0042] Preferably, the predetermined value is between 3 and 10 mm. According to a variant of the invention, the dog clutch sleeve comprises at least a 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.

[0043] 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 external connecting groove and the second internal connecting groove 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.

[0044] 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:

[0045] - the actuation device is attached to the housing body;

[0046] - the housing body includes a support surface for the actuation device;

[0047] - the receiving housing is an annular groove comprising two parallel flat surfaces formed on the two lateral edges;

[0048] - the receiving housing for the dog clutch sleeve is in the form of a groove composed of two lateral rims and a cylindrical bottom and receives the interface component of the output shaft;

[0049] - the lubrication fluid collection part and a lubrication fluid retention part distributed on either side of the first axis of rotation;

[0050] - the lubricating fluid collection part is formed by an end wall offset axially with respect to the closing wall;

[0051] - the lubrication fluid collection section is formed in part by an end wall offset axially relative to the closing wall; - the end of the housing includes an opening which leads to the external cylindrical wall of the housing body to form the lubrication fluid collection section;

[0052] - the end of the crankcase includes an opening which leads to the external cylindrical wall of the end of the crankcase to form the lubricating fluid collection part;

[0053] - Reinforcing arms are arranged between the cylindrical centering edge and the cylindrical inner rim extending along the first axis of rotation in the direction of the actuation device.

[0054] The invention also relates to an internally lubricated transmission, comprising a transmission housing, the transmission housing defining a lubricating fluid level plane at rest when the transmission is in a reference operating position, the transmission further comprising:

[0055] - a transmission element housed in the transmission casing and guided in rotation around a transmission axis,

[0056] - a transmission shaft coupling system incorporating all or part of the characteristics mentioned above, in which the driving shaft is rotationally fixed to the transmission element,

[0057] - a lubrication fluid collection reservoir housed in the transmission casing, located above the oil level plane at rest when the transmission is in its reference operating position, and

[0058] - a lubrication fluid line fitted in the transmission casing which communicates between the lubrication fluid collection tank and the lubrication fluid collection part of the transmission shaft coupling system.

[0059] According to one variant, the lubrication fluid line can be a through drilled hole.

[0060] According to another variant, the lubricating fluid line can be an added pipe.

[0061] According to another embodiment, the lubrication fluid reservoir can be mounted on the transmission housing. The invention also relates to a motor vehicle with a hybrid or electric transmission comprising a driveshaft coupling system and / or a transmission as described above.

[0062] 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:

[0063] [Fig. 1] is a cross-sectional view of a transmission comprising a transmission shaft coupling system according to a first embodiment of the invention;

[0064] [Fig. 2] is a cross-sectional view of the transmission shaft coupling system according to the first embodiment of the invention of Figure 1;

[0065] [Fig. 3] is a partial isometric view of the end of the transmission shaft coupling system of Figure 1;

[0066] [Fig. 4] is a simplified view of the interface end of the output shaft of the actuation device in Figure 1;

[0067] [Fig. 5] is a partial isometric view of the end of a transmission shaft coupling system according to a second embodiment of the invention;

[0068] [Fig. 6] is a cross-sectional view of a transmission shaft coupling system according to a third embodiment of the invention;

[0069] [Fig. 7] is an isometric view of the end of the transmission shaft coupling system of Figure 6;

[0070] [Fig. 8] is an isometric view of the end of a transmission shaft coupling system according to a fourth embodiment of the invention;

[0071] [Fig. 9] is a cross-sectional view of a transmission shaft coupling system according to a fifth embodiment of the invention;

[0072] [Fig. 10] is an isometric view of the end of the transmission shaft coupling system of Figure 9;

[0073] [Fig. 11] is a cross-sectional view of a transmission shaft coupling system according to a sixth embodiment of the invention.

[0074] 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.

[0075] Throughout the description, elements common to several figures retain the same reference.

[0076] 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, 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.

[0077] Figures 1 to 4 illustrate a portion of an electric motor vehicle transmission, comprising an electric motor (not shown), an associated speed reducer, and a driveshaft coupling system located between the speed reducer output and the vehicle wheel. The motor vehicle may be electric or hybrid.

[0078] The electric machine is fixed on a transmission housing 101a, 101b. The transmission housing is generally composed of a main housing 101a supporting the electric machine and a closing housing 101b bearing on the main housing 101a, at the level of a joint plane 108, to seal tightly a cavity delimited by the main housing 101a and the closing housing 101b.

[0079] The electric machine drives a series of transmission shafts mounted within the transmission housing 101a, 101b in a parallel shaft configuration. The transmission further comprises a transmission input shaft and a transmission output shaft 130. Each transmission shaft corresponds to a transmission element 130 housed within the transmission housing and guided in rotation around a transmission axis X3 by means of guide bearings.

[0080] The transmission output shaft 130 carries at least one driven pinion 131 in joint rotation. The transmission output shaft 130 also has a fixed, rotationally connected link to a planet carrier of a differential 132, or constitutes the planet carrier for the differential 132. The differential 132 may be open or limited-slip, depending on the desired properties. The transmission output shaft 130 is guided by two guide bearings 300a, 300b, rotating about the third axis of rotation X3 relative to the transmission housing.

[0081] To lubricate the various components of the transmission 100, the transmission housing 101a, 101b contains lubricating fluid, for example, oil. The guide bearings and gears of the transmission shafts are partially immersed in the oil. The movement of the transmission shafts then agitates the oil by splashing it throughout the entire internal volume of the housing, ensuring the desired lubrication of the entire transmission, including the non-immersed parts.

[0082] For the remainder of this discussion, a reference operating position of the transmission housing 101a, 101b is defined as the three-dimensional orientation in which the housing is installed in a horizontally mounted motor vehicle. In this reference operating position, shown in Figure 1, the transmission output shaft 130 is partially submerged. The transmission housing 101a, 101b is filled with lubricating oil up to a prescribed level corresponding to a resting oil level plane 104. This resting oil level plane 104 is horizontal when the transmission mechanism is in the reference operating position. Each transmission housing model has its own specific oil level limit, determined by its characteristics.If necessary, this oil level limit and the oil level plane at rest 104 can be defined by an oil injection orifice 105, in the sense that, in the reference operating position, the transmission housing 101a, 101b is filled only until the oil level reaches the orifice, and not beyond. The oil level plane at rest is then tangent to the thread of the oil injection orifice 105, allowing a plug to be fitted to it.

[0083] We will first describe the operation of the transmission shaft coupling system in general.

[0084] The driveshaft coupling system 1 is a connecting clutch between two shafts 2 and 3, used in the transmission 100 of a vehicle 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 drive system 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 drive system 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 advantage to leaving the electric machine connected to the vehicle wheel. The connecting clutch is then disengaged.

[0085] The transmission shaft coupling system 1 is kinematically interposed between the speed reducer and the vehicle's wheel shaft 7. 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 is rotationally fixed to the output of the differential 132.

[0086] The transmission drive shaft 2 includes a first transmission spline 2a machined on its end, the first transmission spline is external in this example.

[0087] 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.

[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 suitable for rotating the driving shaft 2 and a second connecting spline 34 suitable for rotating 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.

[0089] To actuate the transmission shaft coupling system 1, an electrically powered actuation device 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, 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 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.

[0090] As illustrated in Figure 2, the interface component 20 is fixed rigidly to the output shaft 40.

[0091] The output shaft 40 pivots within a protective housing 18 of the actuation device 10 and 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.

[0092] The protective housing 18 protects the electric motor 11 and supports the speed reduction device 13. The protective housing 18 is mounted on a housing 50 of the coupling system. The housing 50 of the coupling system is cylindrical with its axis coinciding with the first axis of rotation X and has a secondary passage 58 for the output shaft 40 of the actuating device.

[0093] 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 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. The receiving housing 31 of the dog clutch sleeve 30 is in the form of a groove composed of two lateral edges 32 and a cylindrical bottom 35 and receives the interface component 20 of the actuating device. The two lateral edges 32 support two parallel flat surfaces 32a which are formed from the same material as the dog clutch sleeve.

[0096] In this first embodiment of the invention, the actuating cam 20 has, in cross-section perpendicular to the second axis of rotation Y, a general Reuleaux triangle profile. The actuating cam 20 has two contact areas 20a, 20b bearing on the parallel flat surfaces 32a of the receiving housing; a bearing width L1 along the first axis of rotation X separating the two contact areas is constant throughout the rotation of the output shaft 40 to move from the first extreme disengagement position to the second extreme engagement position.

[0097] To ensure a free movement of the actuating cam 20 within the annular groove without undue friction, an operating clearance is defined between the bearing width L1 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.

[0098] As illustrated in Figure 4, the actuating cam 20 comprises three actuating faces 21 formed as cylindrical segments. The three centers 22 of these cylindrical segments form an isosceles triangle, the principal vertex of which coincides 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 32a. 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 a height 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.

[0099] To ensure the actuating cam 20 moves freely within the receiving housing 31 without unwanted friction, the actuating faces 21 of the actuating cam 20 are connected 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.

[0100] 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.

[0101] 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.

[0102] 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.

[0103] When the teeth of the internal spline of the dog clutch sleeve 30 are to be engaged in the second transmission spline 3a of the driven shaft 3, the rotational speed of the driving shaft 2 is adjusted 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 and 3. When the target speed of the driving shaft 2 is reached, the teeth of the internal spline of the dog clutch sleeve 30 are inserted by rotating the output shaft 40 and the associated actuating cam 20 through a predetermined angular actuation sector between 20° and 180°. The interface component 20 then applies a force to the parallel flat surface 32a of the receiving housing 31 to move the dog clutch sleeve 30.

[0104] Since the rotational speeds of the driven shaft, the driving shaft 2, and the dog clutch sleeve 30 are identical, while the interface component 20 is fixed in rotation relative to the first axis of rotation, there is a relative velocity between the interface component and the dog clutch sleeve. It is therefore necessary to provide specific lubrication at this contact point to prevent overheating by diffusing lubricating fluid from the receiving housing 31.

[0105] For this purpose, the coupling system housing 50 is designed to contain lubricating fluid. The coupling system housing 50 has a general shape of revolution surrounding the driving shaft 2, the driven shaft 3, and the dog clutch sleeve 30 along the first axis of rotation X.

[0106] The housing 50 includes a housing body 51 and a housing end 60 through which the driving shaft 2 passes. The housing end 60 includes a lubrication fluid collection portion 61 and a lubrication fluid retention portion 62 distributed around the first axis of rotation X.

[0107] The lubricating fluid 110 originates from the transmission gearbox 100. When the transmission shafts are rotated, the lubricating oil is sprayed throughout the entire internal volume of the transmission housing 101a, 101b. A lubricating fluid collection reservoir 102, located within the transmission housing above the oil level plane 104 when the transmission is in its reference operating position, collects a certain quantity of oil. The lubricating fluid collection reservoir 102 is partially formed by the transmission housing itself. For example, a partition wall attached to the main housing 101a forms the collection volume.

[0108] A lubrication fluid line 103, located in the main housing 101a, supplies lubrication fluid to the coupling system housing 50. The lubrication fluid collection reservoir 103 and the lubrication fluid collection section 61 of the driveshaft coupling system are connected to deliver lubrication fluid into the driveshaft coupling system 1. The lubrication fluid is delivered by gravity into the coupling system housing 50.

[0109] The lubrication fluid line 103 is, in this case, a through-drilled hole. Alternatively, not shown, the lubrication fluid line 103 can be a separate pipe. The lubrication fluid reservoir 102 can also be mounted on the transmission housing. As illustrated in Figure 1, the lubrication fluid (represented by arrows) collected within the coupling system housing 50 is then directed to the dog clutch sleeve, and subsequently to the receiving housing 31. As the dog clutch sleeve rotates, the lubrication fluid is delivered to the point of contact between the actuating cam 20 and the parallel flat surface 32a. This prevents the contact point from overheating.

[0110] In this first embodiment illustrated in Figure 3, the end of the housing 60 comprises a closing wall 63 extending perpendicularly with respect to the first axis of rotation X and a through-hole 64 for the drive shaft. The edge of the through-hole 64 and the closing wall 63 form the lubricating fluid retention portion 62.

[0111] As illustrated in Figure 3, the closing wall 63 extends beyond the passage orifice 64 so that the passage orifice forms a bore.

[0112] The end of the housing 60 also includes an opening 65 which leads to an external cylindrical wall 52 of the housing to form the lubrication fluid collection part 61. The opening 65 is oriented towards the lubrication fluid line 103 of the transmission housing.

[0113] The opening 65 leads jointly to the outer cylindrical wall 52 of the housing and the closing wall 63 of the housing. In this first mode, the lubrication fluid collection part 61 and the lubrication fluid retention part 62 of the end of the housing 60 are formed from the material of the housing body 51 to form the housing 50 of the coupling system.

[0114] With the opening 65 arranged on the external cylindrical wall 52 of the housing, the end of the housing 60 has an asymmetrical profile with respect to the first axis of rotation X. The asymmetrical profile allows the lubricating fluid to be retained inside the housing 50 of the coupling system.

[0115] The angular positioning of the opening 65 relative to the end of the housing 60 can be adjusted according to the positioning of the lubrication fluid line 103 arranged in the transmission housing.

[0116] As illustrated in Figure 1, the lubricating fluid is brought by gravity into the housing 50 of the coupling system 10. Thus, the secondary passage 58 of the output shaft 40 of the actuation device 10 is arranged opposite the lubricating fluid collection part 61 with respect to the first axis of rotation X, i.e. oriented at 180° with respect to the lubricating fluid line 103.

[0117] In the case of Figure 1, the secondary passage 58 of the output shaft is arranged opposite the lubricating fluid collection part 61 with respect to the first axis of rotation X at an angle of 180°.

[0118] We will now describe, with reference to Figure 5, a second embodiment of the invention, which differs from the first embodiment in that the end of the housing 60 comprises at least one series of openings 65 distributed around the first axis of rotation X along an angular sector between 90° and 180°. The series of openings 65 is formed by radial drilling on the external periphery of the housing 50 of the coupling system.

[0119] In this case, the series of 65 openings is distributed around the first axis of rotation X according to an angular sector of 120°.

[0120] As the series of openings is arranged opposite the lubricating fluid retention part 62 with respect to the first axis of rotation X, the end of the housing 60 has an asymmetrical profile with respect to the first axis of rotation X.

[0121] The series of openings 65 is oriented towards the lubrication fluid line 103 arranged in the transmission housing.

[0122] We will now describe, with reference to Figures 6 and 7, a third embodiment of the invention, which differs from the first embodiment in that the end of the housing 60, comprising the lubrication fluid collection portion 61 and the lubrication fluid retention portion 62, is an additional component attached to the housing body 51 to form the housing 50 of the actuation system, the end of the housing being inserted into a central bore of the housing body. In this third embodiment, the housing body and the end of the housing are two separate parts that form the housing to simplify its shape.

[0123] The end of the housing 60 is inserted into a central bore 55 of the housing body 51.

[0124] The end of the housing 60, produced as an additional component, is obtained by molding plastic material.

[0125] The end of the housing 60 includes a cylindrical centering edge 69 arranged to be inserted into the central bore 55 of the housing body 51 along the first axis of rotation X. The end of the housing 60 includes a passage 64 for the driving shaft 2 and an internal cylindrical rim 68 extending along the first axis of rotation in the direction of the actuation device from the edge of the passage.

[0126] The end of the housing 60 forms in longitudinal section passing through the first axis of rotation X a U-shaped form suitable for retaining the lubricating fluid.

[0127] In this third mode, the interface component 20 is an eccentric actuating rod with respect to the second axis of rotation Y of the actuating device 10, 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.

[0128] More specifically, the eccentric actuating rod 20 is a ball bearing which is inserted into the receiving housing 31 of the dog clutch sleeve 30. The axis of rotation of the ball bearing is parallel and distant from the second axis of rotation Y.

[0129] The rotation of the outer ring of the ball bearing on one of the two parallel flat surfaces 32a of the receiving housing 31 limits heating at the point of contact. The inner ring of the ball bearing is fixed relative to the output shaft 40, for example, secured by means of a rivet or a screw.

[0130] We will now describe, with reference to figure 8, a fourth embodiment of the invention, which differs from the previous embodiment in that the cylindrical centering edge 69 of the end of the housing 60 is discontinuous.

[0131] Consequently, reinforcing arms 67 are arranged between the cylindrical centering edge 69 and the cylindrical inner rim 68 extending along the first axis of rotation X in the direction of the actuating device. The reinforcing arms 67 also contribute to retaining the lubricating fluid.

[0132] In this fourth configuration, the lubrication fluid collection portion 61 is formed in part by an end wall 66 offset axially relative to the closing wall 63. The end wall 66 and the outer cylindrical wall 52 of the housing body 51 form the opening 65 of the lubrication fluid collection portion 61. The housing end 60 also includes a through-hole 64 for the drive shaft and an inner cylindrical rim 68 extending along the first axis of rotation towards the actuating device from the edge of the through-hole. In longitudinal section passing through the first axis of rotation X, the housing end 60 forms a U-shaped profile suitable for retaining the lubrication fluid.

[0133] We will now describe, with reference to figures 9 and 10, a fifth embodiment of the invention, which differs from the third embodiment in that the end of the housing 60 is made in the form of an additional component obtained by stamping a sheet.

[0134] To facilitate stamping, the opening 65 and the passage orifice 64 are common.

[0135] In this example, the end of the housing 60 includes a cylindrical centering edge 69 arranged to be inserted into the central bore 55 of the housing body 51 along the first axis of rotation X. More specifically, the cylindrical centering edge 69 is inserted into a machined groove.

[0136] The housing body 51 includes a longitudinal lubrication fluid flow groove 59 formed on the inner wall of its central bore 55. For example, the longitudinal flow groove 59 is formed directly from a casting. This longitudinal groove 59 facilitates the flow of the lubrication fluid (represented by the arrows) from the end of the housing 60 to the receiving housing 31 of the dog clutch sleeve.

[0137] We will now describe, with reference to Figure 11, a sixth embodiment of the invention, which differs from the third embodiment in that the end of the housing 60 comprises a sealing gasket 70 that rubs against the outer periphery of the drive shaft. In this case, the end of the housing 60 is made in the form of an additional component obtained by molding plastic material.

[0138] An opening 65 leads to the outer cylindrical wall of the housing end 60 to form the lubrication fluid collection part 61. The housing end also includes a cylindrical centering edge 69 arranged to be inserted into the central bore 55 of the housing body 51 along the first axis of rotation X.

[0139] The end of the housing 60 and the housing body 51 are two separate parts that form the housing. The end of the housing 60 bears axially against the housing body 51. The angular positioning of the end of the housing 60 relative to the housing body 51 can be adjusted according to the positioning of the lubrication fluid line provided in the transmission housing.

[0140] 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.

[0141] The transmission shaft coupling system is adapted to receive lubrication fluid from a "passive" internally lubricated speed reducer using the principle of transmission shaft splashing or from an "active" internally lubricated speed reducer using a fluid supply pump.

Claims

1. 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; - a housing (50) of the coupling system being suitable for containing lubricating fluid and having a general shape of revolution surrounding the driving shaft, the driven shaft and the dog clutch sleeve along the first axis of rotation (X), said housing (50) comprises a housing body (51) and a housing end (60) through which the driving shaft passes; - an actuation device (10) supported by the housing comprising an interface component (20) inserted within a receiving housing (31) formed in the dog clutch sleeve, the interface component being arranged to axially move the dog clutch sleeve (30) inside the housing along the first axis of rotation (X) between a first extreme disengagement position and a second extreme coupling position, characterized in that the end of the housing (60) has an asymmetrical profile with respect to the first axis of rotation (X) and comprises a lubrication fluid collection portion (61) and a lubrication fluid retention portion (62) distributed around the first axis of rotation (X).

2. Transmission shaft coupling system (1) according to claim 1, wherein the end of the housing comprises a closing wall (63) extending radially with respect to the first axis of rotation (X), for example perpendicularly, and a passage orifice (64) for the driving shaft, the edge of the passage orifice and the closing wall (63) form the lubricating fluid retention part.

3. Transmission shaft coupling system (1) according to any one of the preceding claims, wherein the end of the housing (60) includes at least one opening (65) which leads to an external cylindrical wall (52) of the housing to form the lubricating fluid collection part.

4. Transmission shaft coupling system (1) according to the combination of claims 2 and 3, wherein at least one opening (65) leads jointly to the outer cylindrical wall (52) of the housing (50) and the closing wall (63) of the housing.

5. Transmission shaft coupling system (1) according to any one of claims 1 to 4, wherein the lubrication fluid collection part (61) and the lubrication fluid retention part (62) of the end of the housing (60) are made of material with the housing body (51).

6. Transmission shaft coupling system (1) according to the preceding claim, wherein the end of the housing (60) comprises at least one series of openings (65) distributed around the first axis of rotation (X) in an angular sector between 90° and 180°, the series of openings (65) being arranged opposite the lubricating fluid retention portion with respect to the first axis of rotation (X).

7. Transmission shaft coupling system (1) according to any one of claims 1 to 4, wherein the housing end (60) comprising the lubrication fluid collection part and the lubrication fluid retention part is an additional component attached to the housing body (51) to form the housing (50) of the actuation system, the housing end (60) being inserted into a central bore (55) of the housing body (51).

8. Transmission shaft coupling system (1) according to the preceding claim, in which the end of the housing (60) includes a cylindrical centering edge (69) arranged to be inserted into the central bore (55) of the housing body (51) along the first axis of rotation (X).

9. Transmission shaft coupling system (1) according to claim 7 or 8, wherein the end of the housing (60) comprises a through-hole (64) for the driving shaft and a cylindrical inner rim (68) extending along the first axis of rotation (X) in the direction of the actuation device from the edge of the passage orifice (64).

10. Transmission shaft coupling system (1) according to any one of claims 7 to 9, wherein the end of the housing (60) includes a sealing gasket (70) which rubs against the outer periphery of the driving shaft (2).

11. Transmission shaft coupling system (1) according to any one of claims 1 to 10, wherein the housing body (60) includes a longitudinal groove (59) for the flow of lubricating fluid arranged on the inner wall of its central bore (55).

12. Transmission shaft coupling system (1) according to any one of claims 1 to 11, wherein the interface component (20) of the actuating device is an actuating cam pivoting about the second axis of rotation (Y) of the actuating device, the actuating cam comprising three actuating faces (21) made in the form of a portion of a cylinder and the three centers of the portion of a cylinder form an isosceles triangle, the actuating cam (20) has two contact areas (20a, 20b) arranged to press against lateral edges (32) of the receiving housing (31).

13. Transmission shaft coupling system (1) according to any one of claims 1 to 11, wherein the interface component (20) of the actuating device 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).

14. Transmission shaft coupling system (1) according to any one of claims 1 to 13, 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.

15. Internally lubricated transmission (100), comprising a transmission housing (101), the transmission housing (101) defining a lubricating fluid level plane at rest (104) when the transmission (100) is in a reference operating position, the transmission (100) further comprising: - a transmission element (130) housed in the transmission housing (101) and guided in rotation about a transmission axis (X3), - a transmission shaft coupling system (1) according to any one of the preceding claims, wherein the driving shaft (2) is rotationally fixed to the transmission element (130), and - a lubrication fluid collection reservoir (102) housed in the transmission casing (101) located above the oil level plane at rest (104) when the transmission (100) is in the reference operating position, and - a lubrication fluid line (103) provided in the transmission housing (101) which communicates between the lubrication fluid collection reservoir (102) and the lubrication fluid collection part (61) of the transmission shaft coupling system.

Images