Coupling unit for the reversible coupling of a drive side with an output side of a drive train, and actuator for such a coupling unit.

Abstract

Coupling unit for reversibly coupling a drive side (2) with an output side (3) of a drive train, comprising a linearly displaceable shift sleeve (8) which sits on a drive element (4) of the drive side (2) and engages with an internal toothing (9) in an external toothing (5) of the drive element (4), and which can be shifted from a disengaged position along the external toothing (5) via an output element (6) of the output side (3) into a coupling position by means of engagement of the internal toothing (9) also in an external toothing (7) of the output element (6), wherein an actuator (10) is provided for shifting the shift sleeve (8), which has a linearly displaceable piston (13) and a shift rod (17) coupled to the piston (13) and coupled to the shift sleeve (8), wherein the piston is located in a housing made of a metal sheet, is guided in a pot-shaped cylindrical component (12),which has an opening on one side through which the shift rod (17) passes and is closed on the other side by a cover (14) which has an opening through which the shift rod (17) passes, wherein the cylinder component (12) is inserted in the assembly position into a form-compatible receptacle (34) in a wall (11) of a gearbox.

Description

The invention relates to a coupling unit for the reversible coupling of a drive side with an output side of a drive train. Such a coupling unit, often also called a "disconnect unit," is used, for example, in the drive systems of a motor vehicle, such as a drive axle, which can also be an electric axle, often called an e-axle. The coupling unit serves to reversibly couple a drive side, where torque is applied, with an output side, to which the torque is to be transmitted and where it is forwarded. It can, for example, be arranged between a drive unit and an intermediate shaft to couple an output of the drive unit, i.e., the drive side, with the input of the intermediate shaft, i.e., the output side.An arrangement between such an intermediate shaft and a differential is also conceivable, in which case the intermediate shaft, at which the torque from the drive is applied, represents the drive side, while the differential, to which the torque is transmitted, represents the output side. The coupling unit can therefore be integrated into such a drive train at different positions. The coupling unit is switchable in order to establish and disengage a torque-resistant coupling between the drive and output sides via a controllable switching device, i.e., an actuator. Such a coupling unit connects two toothed elements on the drive and output sides. This means that an externally toothed drive element, for example, a first gear, is arranged on the drive side, while an externally toothed output element, for example, a second gear, is provided on the output side. These are reversibly connected via a coupling element. Such a coupling element is typically in the form of a linearly displaceable shift sleeve, which sits on the drive element (i.e., is located on the drive side) and engages with the external teeth of the drive element via its internal teeth. An actuator allows the shift sleeve to be moved along the external teeth of the drive element and slid over the output element to couple the drive and output sides, so that the internal teeth of the shift sleeve also engage with the external teeth of the output element.The drive element and the driven element are then rotationally fixed to each other via the shift sleeve which encompasses them both and connects them via the gear mesh, so that the torque present on the drive side can be transmitted to the driven side. Integrating the actuator requires sufficient installation space, which is often not available in a gearbox at a preferred mounting position. As prior art, reference is made, for example, to DE 10 2016 212 807 A1, from which a coupling unit for the reversible coupling of a drive side 38 with an output side 39 of a drive train is known. The invention is based on the problem of providing an improved coupling unit. The problem is solved by a coupling unit according to claim 1 and an actuator according to claim 7. Further developments of the coupling unit and the actuator are the subject of the dependent claims. To solve this problem, a coupling unit for the reversible coupling of a drive side with an output side of a drive train is provided according to the invention, comprising a linearly displaceable shift sleeve which sits on a drive element of the drive side and engages with an internal toothing in an external toothing of the drive element, and which can be shifted from a decoupling position along the external toothing via an output element of the output side, with the internal toothing also engaging with an external toothing of the output element, into a coupling position, wherein an actuator is provided for shifting the shift sleeve, which has a linearly displaceable piston and a shift rod coupled to the piston and connected to the shift sleeve, wherein the piston is guided in a pot-shaped cylinder component made of a metal sheet.which has an opening on one side through which the shift rod passes and is closed on the other side by a cover which has an opening through which the shift rod passes, wherein the cylinder component is inserted in the assembly position into a form-compatible receptacle in a wall of a gearbox. The invention provides for the arrangement or integration of the actuator directly in a corresponding receptacle located in a wall of a gearbox in which such an actuator or coupling unit is installed. This gearbox is, for example, part of an e-axle or another drive unit. The wall can be a wall of the gearbox housing or an intermediate wall that divides the gearbox. By forming this wall with a corresponding, form-compatible receptacle, it is therefore possible to position the actuator directly against the wall and recess it into the receptacle, so that no additional installation space is required for its mounting. The actuator, preferably a hydraulic actuator, has a piston that is guided linearly within a cylinder component or a cylinder section formed therein. According to the invention, this cylinder component is made of a simple, preferably thin, sheet metal, preferably by deep drawing. This cylinder component is accordingly cup-shaped, i.e., it has a specific geometry, and is provided on one side with a corresponding opening or bore that forms a guide section for the switching rod, which is coupled to the piston. On the other side, the cylinder component is closed by a removable cover with an opening through which the switching rod passes, forming a guide section on this side.The cover allows the integration of the switching rod and piston into the cylinder component. Furthermore, by attaching or positioning the cover, the cylinder can be closed, resulting in a sub-assembly consisting of the cylinder component, switching rod, piston, and cover, along with corresponding sealing elements that create pressure chambers into which the hydraulic fluid or compressed air is injected. This sub-assembly can advantageously be pre-assembled, allowing the actuator to be tested for functionality. Installation is also simple, as this sub-assembly only needs to be inserted into the mounting bracket on the wall side and secured. The mounting bracket itself has a corresponding opening through which the switching rod engages. As described, the switching fork, for example, is attached to this rod and is coupled to the switching sleeve. To create the form-compatible recess, the wall-forming component is preferably already profiled accordingly with regard to its basic geometry. This wall component is, for example, an aluminum component or a metal casting, on which the basic three-dimensional geometry of the recess can already be formed during component manufacturing. It would be conceivable to insert the piston directly into the cylindrical recess and guide it against the cylinder wall of the recess via sealing elements. However, this requires that the inner cylinder wall be machined extensively to create a suitable sealing seat for the piston-side sealing element(s). Such machining can, however, lead to the formation of voids, burrs, or similar defects.During piston movement, these surface structures can have an abrasive effect on the sealing element, which can then be destroyed. To counteract this, the invention provides a simple cylinder component made of thin sheet metal, which is inserted into the receptacle (which then only requires relatively rough machining) as a cylinder or guide insert, and which itself has the corresponding sealing surfaces or sealing seats for the piston-side sealing element(s). According to the invention, the sheet metal cylinder component, which serves as an inlay in the receptacle, has a cylinder section that guides the piston and is axially limited by an annular flange. A cylinder flange, forming the guide section, is connected to this annular flange. The pot shape is ultimately formed by the cylinder section and the annular flange. Preferably, an axially extending cylindrical flange adjoins the ring flange, through which the switching rod engages and in which it is guided in the manner of a linear guide. In the assembly position, the cylindrical flange engages in a corresponding opening or bore in the wall, which also allows for centering of the cylinder component or the actuator. Furthermore, the cylinder component may have a radially extending end flange against which the cover rests. Both the flange and the cover have several aligned openings that, in the installed position, are penetrated by mounting screws screwed into the housing wall. The ring flange forms a contact surface against which the cover rests. The flange and the cover have aligned openings. For installation, corresponding mounting screws are inserted through the aligned openings and screwed into corresponding internal threaded holes in the wall, thereby fixing the actuator to the wall. The cover and the mounting screws thus secure and center the cylinder component, ensuring the required concentricity.Furthermore, the preload with which the cylinder component presses on corresponding sealing elements provided on the receiving side can also be generated via the cover screw. As described, due to the need for shape compatibility, the receptacle is also advantageously cup-shaped, allowing the cylinder component to be fully inserted into it. The receptacle, as described, has a bore into which the cylinder flange engages in the assembled position. Furthermore, the flange of the cylinder component is advantageously positioned against the end face of the wall, thus providing axial support in conjunction with the axial support provided by the annular flange forming the base of the cylinder section. As described, the device preferably includes one or more sealing elements that seal towards the cylinder component, so that if a corresponding volume is to be separated and sealed via the wall or partition, a corresponding seal is also provided at this opening or interface. The piston and the cover each have corresponding sealing elements that seal the piston and the cover against the cylinder component and the shift rod. These seals form the corresponding pressure chambers, one in front of and one behind the piston, allowing the piston to be actively moved in one direction or the other and enabling the shift sleeve to be moved to specific positions, i.e., the disengaged and engaged positions. In addition to the coupling unit itself, the invention relates to an actuator for such a coupling unit, comprising a pot-shaped cylinder component made of a metal sheet in which a piston is linearly displaceable, and a switching rod coupled to the piston, wherein the cylinder component has an opening on one side through which the switching rod passes and is closed on the other side by a cover which has an opening through which the switching rod passes. The cylinder component can have a cylinder section that guides the piston, which is axially limited by a ring flange, to which a cylinder flange is attached, forming the opening and thus the guide section there. The cylinder component can further have a terminal, radially extending flange against which the cover rests, wherein the flange and the cover have several aligned openings which are penetrated by fastening screws screwed into the housing wall in the assembly position. Sealing elements provided on the piston and the cover ensure a proper seal between the piston and the cover and the cylinder component, as well as the shift rod. The invention is explained below with reference to exemplary embodiments and the drawings. The drawings are schematic representations and show: Fig. 1 a basic representation of a coupling unit according to the invention, and Fig. 2 an enlarged partial view of the actuator of the coupling unit as a subassembly. Fig. 1 shows a schematic representation of a coupling unit 1 according to the invention, which can also be referred to as a coupling device, and which serves to couple a drive side 2, where a torque is applied or present, with an output side 3, to which the torque is to be transmitted and where it is further distributed. A drive element 4 is provided on the drive side 2, which has external teeth 5. The drive element 4 is, for example, a gear or an externally toothed shaft. On the output side 3, an output element 6 is provided, which has external teeth 7. This output element 6 can also be a gear, an externally toothed shaft, or the like. The external teeth 5 and 7 are linear radial teeth with the same pitch and radius. To couple the drive element 4 to the output element 6 in a rotationally fixed manner, a shift sleeve 8 is provided, which is axially displaceable. It has internal teeth 9, with which, in the decoupling position shown in Fig. 1, it fully engages the external teeth 5 of the drive element 4. This means that in the decoupling position, the shift sleeve 8 is coupled only to the drive element 4. Torque transmission to the output element 6 is not possible in this position.However, if torque transmission is required, the shift sleeve 8 must be axially displaced and slid over the output element 6, specifically its external teeth 7, so that the internal teeth 9 of the shift sleeve 8 are pushed into the external teeth 7 and mesh with them. Simultaneously, the engagement of the internal teeth 9 with the external teeth 5 remains, so that the drive element 4 and the output element 6 are rotationally fixedly coupled via the shift sleeve 8. To achieve this movement of the shift sleeve 8, an actuator 10, which is a hydraulic actuator, is provided. It is integrated into a wall 11 of a gearbox, for which purpose the wall 11 has a cup-shaped receptacle 34 with an opening 35. The actuator 10 has a cup-shaped cylinder component 12 formed from a sheet metal part, which is positively inserted into the form-compatible receptacle 34 and is completely recessed therein. A cylinder section 36, which forms a guide cylinder and in which a piston 13 is arranged, is provided in the cylinder component 12. The cylinder component 12 is closed axially by a cover 14. Within the cylinder component 12, the piston 13 is axially displaceable by means of a hydraulic fluid, for which purpose a first pressure chamber 15 is provided, which is located between the piston 13 and the cover 14.On the opposite side, a second pressure chamber 16 is located between the piston 13 and the end wall of the insert 12. Depending on which pressure chamber 15, 16 the hydraulic fluid is injected into, the piston is moved in one direction or the other. Furthermore, a switching rod 17 is provided, which extends through the cylinder component 12 and the cover 14 and is guided thereon in a sealed manner via corresponding sealing elements 18, 19. The switching rod 17 is axially movable, for which purpose it is coupled to the piston 13. For this purpose, two axial stops 20, 21 are provided on the switching rod 17, which are realized via two retaining rings 24, 25 received in respective grooves 22, 23. The piston 13 is slightly axially displaceable between these axial stops 20, 21. This axial displacement is possible against a spring element 26, which is designed as a wave spring, disc spring, or corresponding spring assembly and is received in an annular recess 27 of the piston. The spring element 26 is supported on one side by the piston 13 or the bottom of the recess 27, and on the other side by the axial stop 20 or a support disc 28 supported by the snap ring 24. When a fluid is forced into the pressure chamber 15, the piston 13 is moved to the left until the spring element 26 rests against the support disc 28, unless this is already the case. The shift rod 17 is also connected to a driver 29, for example, a shift fork, which in turn is connected to the shift sleeve 8 via a corresponding positive engagement.The shift sleeve 8, which rotates with the drive element 4, has, for example, a circumferential annular projection 30 which engages in a corresponding receiving groove 31 on the shift fork 29. The cylinder component 12 further comprises an annular flange 37 adjoining cylinder section 36, to which a cylinder flange 38 is connected, engaging in the opening 35. The cylinder flange 38 is penetrated by the switching rod 17 and serves as a guide section or linear guide for the switching rod 17 on this side. On the other side, the cylinder component 12 has a flange 39 extending radially outwards, which, in the assembly position, rests against the end face of the wall 34 and on which the cover 14 sits. The cover 14 is fastened to the wall 11 by means of several fastening screws 40, which pass through openings provided in the cover 14 and the flange 39 and are screwed into internally threaded bores provided in the wall 11. The cylinder component 12 is sealed in the receptacle 34 via sealing elements 41, whereby the preload on the sealing elements is generated via the screwing of the cover 14. The piston is provided with two sealing elements 32, 33, which provide a seal to the shift rod 17 on one side and to the cylinder component 12 on the other. The cover is also provided with two sealing elements 42, 43, which provide a seal to the cylinder component 12 and to the shift rod 17. The shift rod 17 is itself provided with a sealing element 44, which seals against the cylinder flange 38. The sealing elements 32, 33, 42, 43 are received in corresponding grooves. Fig. 2 shows an enlarged view of the actuator 10 as a mere subassembly. This is clearly a self-contained, pre-assembled unit that can be tested as such before assembly. For this purpose, hydraulic fluid is fed, for example, through supply bores 45, 46 provided on the cylinder component 12, either into the pressure chamber 15 or into the pressure chamber 16 to move the piston 13. During assembly, this subassembly simply needs to be inserted into the receptacle 34 by passing the switching rod 17 through the opening 35 and secured using the fastening screws 40. Also shown is a displacement sensor 47 provided on the actuator, which serves for the precise position detection of the switching rod 17 and thus of the switching sleeve 8. The displacement sensor 47 comprises a sensor 48, e.g., a Hall sensor, which is housed in a sensor housing 49. The sensor housing 49 is L-shaped and fixed by a fastening screw 40. One leg of the housing extends axially adjacent to the switching shaft 17, with the sensor 48 being arranged in this leg and thus adjacent to the switching rod 17. A magnetic element 50 is axially arranged on the switching rod 17, e.g., glued and covered with a protective cap 51. It interacts with the sensor 48, the signals of which are evaluated by a control and processing unit for the precise position detection of the magnetic element. Reference symbol list 1 Coupling unit 2 Drive side 3 Output side 4 Drive element 5 External toothing 6 Output element 7 External toothing 8 Shift sleeve 9 Internal toothing 10 Actuator 11 Wall 12 Cylinder component 13 Piston 14 Cover 15 Pressure chamber 16 Pressure chamber 17 Shift rod 18 Sealing element 19 Sealing element 20 Axial stop 21 Axial stop 22 Groove 23 Groove 24 Retaining ring 25 Retaining ring 26 Spring element 27 Recess 28 Support washer 29 Driver 30 Ring projection 31 Shift fork 32 Sealing element 33 Sealing element 34 Receptacle 35 Opening 36 Cylinder section 37 Ring flange 38 Cylinder flange 39 Flange 40 Mounting screw 41 Sealing element 42 Sealing element 43 Sealing element 44 Sealing element 45 Feed bore 46 Feed bore 47 Position sensor 48 Sensor 49 Sensor housing 50 Magnetic element 51 Protective cap

Claims

Coupling unit for reversibly coupling a drive side (2) with an output side (3) of a drive train, comprising a linearly displaceable shift sleeve (8) which sits on a drive element (4) of the drive side (2) and engages with an internal toothing (9) in an external toothing (5) of the drive element (4), and which can be shifted from a disengaged position along the external toothing (5) via an output element (6) of the output side (3) into a coupling position by means of engagement of the internal toothing (9) also in an external toothing (7) of the output element (6), wherein an actuator (10) is provided for shifting the shift sleeve (8), which has a linearly displaceable piston (13) and a shift rod (17) coupled to the piston (13) and coupled to the shift sleeve (8), wherein the piston is located in a housing made of a metal sheet, is guided in a pot-shaped cylindrical component (12),which has an opening on one side through which the shift rod (17) passes and is closed on the other side by a cover (14) which has an opening through which the shift rod (17) passes, wherein the cylinder component (12) is inserted in the assembly position into a form-compatible receptacle (34) in a wall (11) of a gearbox. Coupling unit according to claim 1, characterized in that the cylinder component (12) has a cylinder section (36) guiding the piston (13), which is axially limited by a ring flange (37) to which a cylinder flange (38) is attached, which forms the guide section. Coupling unit according to claim 1 or 2, characterized in that the cylinder component (12) has a terminal, radially extending flange (39) against which the cover (14) rests, wherein the flange (39) and the cover (14) have several mutually aligned openings which are penetrated by fastening screws (40) screwed into the wall (11) in the assembly position. Coupling unit according to claim 2 or 3, characterized in that the receptacle (34) is cup-shaped and has a bore (35), wherein in the assembly position the cylinder flange (38) engages in the bore (35) and / or the flange (39) rests against an end face of the wall (11). Coupling unit according to one of the preceding claims, characterized in that one or more sealing elements (41) are provided in the receptacle (34) which seal towards the cylinder component (12). Coupling unit according to one of the preceding claims, characterized in that the piston (13) and the cover (14) each have sealing elements (32, 33, 42, 43) by which the piston (13) and the cover (14) are sealed to the cylinder component (12) and to the switching rod (17). Actuator for a coupling unit, comprising a pot-shaped cylinder component (12) made of a metal sheet, in which a piston (13) is linearly displaceable, and a switching rod (17) coupled to the piston (13), wherein the cylinder component (12) has an opening on one side through which the switching rod (17) passes and is closed on the other side by a cover (14) which has an opening through which the switching rod (17) passes. Actuator according to claim 7, characterized in that the cylinder component (12) has a cylinder section (36) guiding the piston (13), which is axially limited by a ring flange (837), to which a cylinder flange (38) is attached, which forms the guide section. Actuator according to claim 7 or 8, characterized in that the cylinder component (12) has a terminal, radially extending flange (39) against which the cover (14) rests, wherein the flange (39) and the cover (14) have several mutually aligned openings which are penetrated by fastening screws (40) screwed into the wall in the assembly position. Actuator according to one of claims 7 to 9, characterized in that sealing elements (32, 33, 42, 43) are provided on the piston (13) and on the cover (14) respectively, by means of which the piston (13) and the cover (14) are sealed to the cylinder component (12) and to the switching rod (17).

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