Drive unit for a hybrid powertrain

Abstract

The invention relates to a drive unit (1) for a hybrid powertrain, comprising an internal combustion engine (2), an electric motor (4) and a decoupling clutch (6) radially arranged within a rotor (5) of the electric motor (4) between a crankshaft (3) of the internal combustion engine (2) and the rotor (5), wherein a torsional vibration isolation device (8) is connected downstream of the rotor (5), wherein the torsional vibration isolation device (8) is connected in a rotationally fixed manner to the rotor (5) by means of a plug connection (22), and the plug connection (22) is formed by an inner profiled portion associated with the rotor (5) and an outer profiled portion complementarily configured on the torsional vibration isolation device (8). In order to avoid noise and excessive wear at the plug connection (22), a pretensioning device (30) of the plug connection (22) comprises at least one pretensioning element (31) fastened to the rotor (5), which adjusts the pretensioning in the circumferential direction relative to a support surface (34) of the torsional vibration isolation device (8).

Description

Technical Field

[0001] The present invention relates to a drive unit for a hybrid powertrain, comprising an internal combustion engine, an electric motor, and a disengagement clutch radially disposed within the rotor between the crankshaft of the internal combustion engine and the rotor of the electric motor, wherein a torsional vibration isolation device is connected downstream of the rotor, wherein the torsional vibration isolation device is rotatably connected to the rotor by means of a plug-in connection, and the plug-in connection is formed by an inner contoured portion associated with the rotor and an outer contoured portion complementaryly formed on the torsional vibration isolation device. Background Technology

[0002] Such a drive unit is known, for example, from document WO 2015 / 172784 A2. The drive unit comprises an internal combustion engine with torsional vibration having a crankshaft and an electric motor having a rotor. A disengagement clutch is provided between the crankshaft and the rotor. A centrifugal pendulum is connected downstream of the rotor, and the pendulum's support blocks are torsionally fixedly housed on the end side of the rotor.

[0003] A rotary assembly for such a drive unit is known, for example, from document DE 10 2014 214 634 A1, in which the components of the torsional vibration damper are directly and torsionalally fixed to the friction plate carrier. Interfering noise occurs due to circumferential clearances in the connection between the friction plate carrier and the components fixed thereon, caused by tolerances or installation.

[0004] Furthermore, an unpublished patent application, 10 2019 123 794.7, discloses a drive unit having a damped plug-in connection between a rotor and a torsional vibration isolation device. The contents of that patent application are incorporated herein by reference in their entirety. Summary of the Invention

[0005] The object of this invention is to improve such a drive unit. In particular, the object of this invention is to provide a drive unit in which noise generation and excessive wear are reduced at the rotational engagement connection between the rotor and the downstream torsional vibration isolation device.

[0006] The objective is achieved by a drive unit for a hybrid powertrain. Advantageous embodiments are described herein.

[0007] The proposed drive unit design is for a hybrid powertrain and includes, for example, an internal combustion engine with torsional vibration, an electric motor, and a disengagement clutch radially disposed within the rotor between the crankshaft of the internal combustion engine and the rotor of the electric motor. The stator of the electric motor can be fixedly connected to the housing of the internal combustion engine. The crankshaft and rotor are preferably arranged coaxially with each other. The disengagement clutch can be arranged entirely radially within the rotor and axially within the rotor's structural space. A clutch actuation device for automatically operating the disengagement clutch can be arranged entirely radially within the electric motor's structural space.

[0008] The disengagement clutch can be configured as a friction plate clutch, having layered friction plates on the input and output sides, axially loaded by a clutch operating device. These friction plates are alternately and torsionally engaged in an inner friction plate carrier on the input side and an outer friction plate carrier fixedly connected to or formed as a single piece therefrom. A torsional vibration damper, such as a dual-mass flywheel, can be provided between the crankshaft and the disengagement clutch. The disengagement clutch can be mounted on an intermediate shaft coaxial with the crankshaft and rotor, centered at the stator, with the output component of the torsional vibration damper and the inner friction plate carrier torsionally connected to the intermediate shaft.

[0009] A torsional vibration isolation device is connected downstream of the rotor, wherein the torsional vibration isolation device is rotatably connected to the rotor by means of a plug-in connection. The plug-in connection includes an inner profile portion, which may be the same as, for example, a profile portion for anti-torsional reception of the output-side friction plate on the outer friction plate carrier, or be independently connected to the rotor or machined thereon and provided on the outer friction plate carrier. The inner profile portion may be configured as a partially toothed portion, that is, configured as having teeth that are not completely circumferential and alternate with tooth roots, or configured as a complete internal toothed portion having teeth that are regularly arranged circumferentially and alternate with tooth roots. A complementary outer profile portion engages with the inner profile portion of the disengagement clutch, which may, for example, be partially or completely formed as an external toothed portion. For example, the flange component of the torsional vibration isolation device may have a disc component with circumferential external teeth or multiple arms distributed circumferentially, wherein a partial outer profile portion complementary to the inner profile portion is provided radially outward at the arm portion.

[0010] To avoid noise, such as clicking sounds caused by tolerances, and / or to improve the engagement process of the mating connection, the circumferential clearance of the mating connection due to installation in the profiled portion, and / or to reduce excessive wear caused by the circumferential clearance at the mating connection, the circumferential clearance of the mating connection is prevented in a decaying manner. For example, noise can be caused by residual rotational unevenness in an internal combustion engine. The circumferential clearance is understood, for example, as the free space between the teeth and tooth surfaces of the profiled portion of the mating connection, and should not be confused with the circumferential guidance of a torsional vibration isolation device, which can always be carried out by means of the circumferential clearance and should also be carried out by means of the circumferential clearance to avoid high wear due to transmission distortion.

[0011] The torsional vibration isolation device is preferably axially floating at the plug-in connection and axially fixed on the transmission side, for example, on the transmission input shaft. The rotor and disengagement clutch are axially fixed relative to the stator, allowing for tolerance compensation, elimination of axial deviations of the transmission input shaft, and elimination of oscillating motion, such as at the plug-in connection with circumferential clearance but with attenuated circumferential clearance, where angular deviations exist. While this compensation motion can be performed under force-consuming conditions due to the attenuated circumferential clearance, the absence of free, clicking circumferential clearance due to its attenuation prevents this type of movement.

[0012] According to an advantageous embodiment of the proposed drive unit, the outer profiled portion is elastically pre-tightened in the circumferential direction within the inner profiled portion. This means that the outer profiled portion and the inner profiled portion are pressed together by at least one element pre-tightened in the circumferential direction. The rigidity of the at least one pre-tightening element is set such that the resulting restoring force is attenuated by torsional vibration.

[0013] To establish attenuation of the plug-in connection, at least one preload element of the preload device is screwed, riveted, crimped, or locked to the rotor, for example, at its free end. This at least one preload element can be configured as a single annular member. Alternatively, multiple preload elements, such as annular segments, can be fixedly connected to the rotor circumferentially. For example, the single annular preload element can have at least one axial protrusion received in one piece on the fastening ring, which axially overlaps and preloads the corresponding, as-belonging, support surface of the torsional vibration isolation device in the circumferential direction. Multiple, preferably three to six, protrusions distributed circumferentially on the fastening ring can axially overlap three to six support surfaces of the torsional vibration isolation device and preload unilaterally or bilaterally in the circumferential direction, that is, in the traction or propulsion direction, preferably only in the traction direction of the drive unit. Multiple preload elements can each have one or more axial protrusions. To form a corresponding support surface axially opposite to at least one protrusion, a recess with a radially oriented support surface can be easily introduced into the disc component of the torsional vibration isolation device, into which at least one protrusion of at least one preload element is axially engaged. To widen the axial clearance space of the protrusion, thereby increasing the axial tolerance of axially adjacent components, such as the output component of a torsional vibration damper, the corresponding support surface can be shifted away from the plane of the disc component along the axial direction of the protrusion. For this purpose, an open embossed portion with a support surface can be imprinted from the disc component.

[0014] At least the corresponding support surface area of ​​the disc component, preferably the entire disc component, can be rigidly constructed. Furthermore, at least one preload element can be rigidly constructed to have a predetermined elasticity. The corresponding support surface can be manufactured during the manufacturing of the disc component using a die-cutting method.

[0015] A torsional vibration isolation device may form or include a torsional vibration damper. A plug-in connection is preferably formed between the rotor and the input component of the torsional vibration damper. Downstream of the input component, against the action of a spring device, is an output component that is rotatably arranged relative to the input component about a rotational axis, such as about the rotational axis of a transmission input shaft. This output component is torsionally connected to and axially fixed to the transmission input shaft, for example, by means of an output hub. The input component of the torsional vibration damper may include two axially spaced, interconnected, and rotatably centered side components on the output hub. Between these side components is an output component configured as a disc component connected to the output hub. The spring device may be formed by helical compression springs distributed circumferentially, each helical compression spring housed in an axially opposing spring window in one of the side components and the disc component, and loaded by them in the circumferential direction. One of the side components here has at least one support surface and forms a plug-in connection radially outward with an inner profiled portion of the rotor by means of an outer profiled portion. Alternatively, another disc component may be connected to one of the disc components of the input component, such as by riveting, and the other disc component forms an outer contour portion.

[0016] One or more support surfaces for forming a resiliently pre-tightened plug connection in the circumferential direction may be respectively provided on the recess of the disc component of the input component, wherein at least one pre-tightening element is provided directly axially adjacent to the disc component by means of at least one protrusion that axially overlaps the support surfaces and pre-tightens them in the circumferential direction.

[0017] A spring device formed by helical compression springs distributed circumferentially can be installed between the disc components of the input and output components. The helical compression springs are respectively housed in axially opposite spring windows of the disc components and can be loaded circumferentially by their radial window wall portions. To save structural space and circumvent the functional limitations of the spring stiffness of the spring device, corresponding support surfaces (multiple) can be arranged radially and circumferentially between the two spring windows, respectively, so that the helical compression springs are advantageously positioned as far outward as possible within the corresponding disc components, independent of the radial arrangement of the corresponding support surfaces.

[0018] Torsional vibration isolation devices or torsional vibration dampers can be partially or completely integrated into the structural space of the electric motor. Attached Figure Description

[0019] With the help ofFigures 1 to 6 The embodiments shown in the figures illustrate the invention in detail.

[0020] Figure 1 A cross-section of the upper portion of the drive unit arranged around the axis of rotation is shown.

[0021] Figure 2 Showing by means of and Figure 1 A 3D partial view of the torsional vibration damper connected to the drive unit via a plug-in connection of the rotor in the area of ​​the preload device.

[0022] Figure 3 Show Figure 2 A 3D partial cross-section view of the torsional vibration damper in the area of ​​the preload device.

[0023] Figure 4 The diagram shows a cross-sectional detail of a torsional vibration damper in the area of ​​a preload device with a modified support surface.

[0024] Figure 5 Show Figure 4 A 3D partial view of the torsional vibration damper in the area of ​​the preload device, and

[0025] Figure 6 Show Figure 4 and 5 A partial view of the torsional vibration damper in the area of ​​the preload device. Detailed Implementation

[0026] Figure 1 A cross-section of the upper portion of a drive unit 1 arranged around a rotation axis is shown. The drive unit 1 includes: an internal combustion engine 2, with only a crankshaft 3 shown; an electric motor 4 having a rotor 5; a disengagement clutch 6 disposed within the rotor 5; a torsional vibration damper 7 disposed between the crankshaft 3 and the disengagement clutch 6; and a torsional vibration isolation device 8 connected downstream of the rotor 5, which in the shown embodiment is configured as a torsional vibration damper 9. In other embodiments, the torsional vibration isolation device 8 may be configured as a centrifugal pendulum or a combination of a torsional vibration damper and a centrifugal pendulum.

[0027] The stator 10 of the electric motor 4 is fixedly connected to the housing (not shown) of the internal combustion engine 2 and the shaft section 12 is rotatably accommodated by means of a hollow shaft shoulder 11. The operating device 13 of the disengagement clutch 6 is rotatably accommodated on the hollow shaft shoulder 11.

[0028] The torsional vibration damper 7 is fastened to the crankshaft 3 on the input side and engages with the shaft section 12 in a torsional manner on the output side.

[0029] The inner friction plate support 14 of the disengagement clutch 6 is torsionally connected to the shaft section 12. The outer friction plate support 15 is disposed in the inner circumference of the rotor 5. The friction plates 16 and 17 of the disengagement clutch 6 are axially and alternately layered and torsionally engaged between the inner friction plate support 14 and the outer friction plate support 15, and can be axially loaded toward the end friction plate 18 by the operating device 13 in order to operate the disengagement clutch 6.

[0030] The outer friction plate carrier 15 has an inner profiled portion 19—in this case, an inner toothed portion—to accommodate the friction plate 17 and the torsional vibration isolation device 8 in a torsional manner.

[0031] The inner contoured portion 19, together with the outer contoured portion 20—in this case, the outer toothed portion—that is complementary to the inner contoured portion of the disc component 21 of the torsional vibration isolation device 8, forms a plug-in connection 22. The disc component 21 is radially internally connected to the disc component 23. The disc component 23 is axially spaced from the disc component 24. The disc components 21, 23, and 24 form the input component 25 of the torsional vibration damper 9 of the torsional vibration isolation device 8.

[0032] A disc component 26 is axially disposed between disc components 23 and 24, and is connected to, for example, by welding, an output hub 27, forming an output component 28 together with the output hub. The output hub 27 is torsionally connected to a transmission input shaft 29 (not shown) of a transmission. The disc component 23, and thus the input component 25, is rotatably centered on the output hub 27. The output hub 27, and thus the torsional vibration isolation device 8, is axially fixed to the transmission input shaft 29. Axial compensation between the crankshaft 3 and the transmission input shaft 29 therefore occurs within the plug-in connection 22. For this purpose, the inner contoured portion 19 and the outer contoured portion 20 are axially floating.

[0033] A spring device 36 acting in the circumferential direction is provided between one side of the disc components 23, 24 and the other side of the disc component 26. The helical compression springs 37 of the spring device are distributed circumferentially in the spring windows 38, 39, 40 left by the disc components 23, 24 and 26, and can be loaded by the radially oriented window wall portion when the disc components 23, 24 rotate relative to the disc component 26.

[0034] The plug-in connection 22 has a circumferential gap with tolerance or related to installation to simply form an engagement. To eliminate this circumferential gap during operation of the drive unit 1 and thus avoid noise, such as clicking noise, the outer profiled portion 20 is pre-tightened relative to the inner profiled portion 19 in the circumferential direction along the rotational direction. For this purpose, a pre-tightening device 30 is formed between the rotor 5 and the disc component 23. This is achieved by means of screws 35 fastening at the end side of the rotor 5 to a pre-formed, annular pre-tightening element 31 made of sheet metal and adapted, for example, by hardening to a predetermined rigidity or elasticity. This pre-tightening element has a radially inwardly elastically formed protrusion 32, which axially engages in the circumferential direction with a recess 33 of the disc component 23 under the predetermined pre-tightening condition, and pre-tightens the support surface 34 of the recess 33 at least circumferentially toward the inner profiled portion 19, thereby pre-tightening the outer profiled portion 20 toward the inner profiled portion 19 in the pre-tightening direction. Preferably, the pre-tensioning is performed along the traction direction, such that the inner contoured portion 19 and the outer contoured portion 20 are pre-tensioned and abut against each other under traction conditions, and when the torque changes along the propulsion direction, the outer contoured portion 20 resists the action of the pre-tensioning device 30 and moves to the opposite edge of the inner contoured portion 19.

[0035] Figure 2 Reference Figure 1 The drive unit 1 shows a 3D detailed view of the torsional vibration isolation device 8 configured as a torsional vibration damper 9, wherein the input component 25 of the torsional vibration damper 9 is shown, the input component having disc components 21, 23, 24 and a preload element 31 of the preload device 30 shown separately from the rotor 5.

[0036] The disc component 21 carries the outer contour portion 20 for forming an insertion connection 22 with the inner contour portion 19 of the rotor 5, and is riveted to the disc component 23 radially inward. Disc components 23 and 24 house the invisible disc component 26 of the output component 28 of the torsional vibration damper 9 between them. During relative movement between the disc components 23, 24, and 26, and between the input component 25 and the output component 28, the helical compression springs 37, shown here alternately and distributed circumferentially, are effectively loaded in the circumferential direction.

[0037] For pre-tightening the insertion connection 22, the pre-tightening element 31 fastened to the rotor 5 is configured with axially distributed protrusions 32, which are elastic, extend from the fastening ring 41 in the circumferential direction, and are axially U-shaped tongues 42. Under pre-tightening conditions, the protrusions 32 axially engage with the recesses 33 of the disc component 23 in the circumferential direction, thereby loading the support surface 34 of the recesses 33. Thus, the pre-tightening element 31, which is torsionally accommodated on the rotor 5, pre-tightens the disc component 21, which is torsionally fastened to the disc component 23, relative to the rotor 5 in the circumferential direction at the insertion connection 22.

[0038] Figure 3 Show Figure 1 and 2 A 3D cross-sectional view of a torsional vibration damper 9, which has disc components 21, 23, 24 and a helical compression spring 37.

[0039] The pretensioning device 30 is formed by a pretensioning element 31 having a protrusion 32 that engages axially in a recess 33 of the disc component 23 and loads a support surface 34 in the circumferential direction, preferably the traction direction.

[0040] Figures 4 to 6 Detailed views of the drive unit 1, which has a pretensioning device 30a that is modified relative to the pretensioning device 30, are shown relative to the preceding figures.

[0041] Figure 4 This is shown with rotor 5 ( Figure 1 A torsional vibration damper 9a is a preload device 30a acting between the input component 23a and the disc component 24a. Disc components 21a, 23a, and 24a, connected to each other, form an input component 25a, and the output component 28a of the torsional vibration damper 9a includes a disc component 26a. A spring device 36a is provided between the input component 25a and the output component 28a, the spring device having helical compression springs 37a distributed circumferentially between the disc components 23a, 24a, and 26a.

[0042] The pre-tightening device 30a functions between the rotor 5 and the disc component 23a and pre-tightens the insertion connection 22 along the circumferential direction, preferably along the traction direction. Figure 1 To address this, a preload element 31a is fixedly fastened to the rotor 5. An axial protrusion 32a engages here with a recess 33a that is axially imprinted toward the preload element 31a, having a support surface 34a. By imprinting the support surface 34a, the contact area is axially shifted away from the disc component 26a toward the preload element 31. This reduces the axial expansion of the protrusion 32a and increases the tolerance distance with the disc component 26a, effectively eliminating contact between the protrusion and the relatively rotating disc component.

[0043] The embossing of the support surface 34 is preferably provided by means of stamping during the manufacturing of the disc component 23a by means of die processing.

[0044] Figure 5 and 6 Show Figure 4 A detailed view of the torsional vibration damper 9a having disc components 21a and 23a. The recess 33a of the disc component 23a has an axially imprinted support surface 34.

[0045] List of reference numerals in the attached diagram:

[0046] 1. Drive Unit

[0047] 2. Internal Combustion Engine

[0048] 3 Crankshaft

[0049] 4 Electric motor

[0050] 5 rotors

[0051] 6. Disengage the clutch

[0052] 7 Torsional vibration damper

[0053] 8 Torsional vibration isolation device

[0054] 9. Torsional vibration damper

[0055] 9a Torsional Vibration Damper

[0056] 10 stators

[0057] 11 Hollow shaft with protruding shoulder

[0058] 12 Shaft Section

[0059] 13 Control device

[0060] 14 Internal friction plate bearing components

[0061] 15 External friction plate bearing component

[0062] 16 Friction Plates

[0063] 17 Friction Plates

[0064] 18 End friction plates

[0065] 19. Inner contour section

[0066] 20 Outer contour section

[0067] 21 disk components

[0068] 21a disk components

[0069] 22. Plug-in connection

[0070] 23 disk components

[0071] 23a disk components

[0072] 24-disc component

[0073] 24a disk components

[0074] 25 Input Components

[0075] 25a Input Component

[0076] 26-disc component

[0077] 26a disk components

[0078] 27 Output Hub

[0079] 28 Output components

[0080] 28a Output Component

[0081] 29. Gearbox input shaft

[0082] 30 Pre-tightening device

[0083] 30a Pre-tightening device

[0084] 31 Preload element

[0085] 31a Preload element

[0086] 32. Protrusion

[0087] 32a Protrusion

[0088] 33 recess

[0089] 33a recess

[0090] 34 Support surface

[0091] 34a Support surface

[0092] 35 screws

[0093] 36. Spring device

[0094] 36a Spring device

[0095] 37 Helical Compression Spring

[0096] 37a Helical Compression Spring

[0097] 38 Spring Window

[0098] 39 Spring windows

[0099] 40 Spring Window

[0100] 41 Fastening ring

[0101] 42 Tongue-shaped component

[0102] d Rotation axis

Claims

1. A drive unit (1) for a hybrid powertrain, comprising an internal combustion engine (2), an electric motor (4), and a disengagement clutch (6) radially disposed within the rotor (5) between a crankshaft (3) of the internal combustion engine (2) and a rotor (5) of the electric motor (4), wherein a torsional vibration isolation device (8) is connected downstream of the rotor (5), wherein the torsional vibration isolation device (8) is rotatably connected to the rotor (5) by means of a plug-in connection (22), and the plug-in connection (22) is formed by an inner contoured portion associated with the rotor (5) and an outer contoured portion complementaryly formed on the torsional vibration isolation device (8). Its features are, The pre-tightening device (30, 30a) of the plug-in connection (22) includes at least one pre-tightening element (31, 31a) fastened to the rotor (5), the at least one pre-tightening element adjusting the pre-tightening relative to the support surface (34, 34a) of the torsional vibration isolation device (8) in the circumferential direction, the at least one pre-tightening element (31, 31a) having at least one axially extending protrusion (32, 32a), the protrusion axially overlapping and pre-tightening the support surface (34, 34a) which is one piece provided on the torsional vibration isolation device (8).

2. The driving unit (1) according to claim 1, characterized in that, The torsional vibration isolation device (8) includes a torsional vibration damper (9, 9a), the input part (25, 25a) of which is connected to the rotor (5) by means of the plug connection (22), and the output part (28, 28a) of the torsional vibration damper (9, 9a) has an output hub, wherein spring devices (36, 36a) are arranged circumferentially between the input part (25, 25a) and the output part (28, 28a).

3. The driving unit (1) according to claim 2, characterized in that, The input component (25, 25a) has two axially spaced, interconnected disc components (23, 23a, 24, 24a), wherein the plug-in connection (22) is formed indirectly or directly between at least one disc component (23, 23a) and the rotor (5).

4. The driving unit (1) according to claim 3, characterized in that, The support surface (34, 34a) is disposed at the recess (33, 33a) of the disk component (23, 23a) of the input component (25, 25a).

5. The driving unit (1) according to claim 3, characterized in that, The corresponding support surface (34a) extends axially from the disc component (23a) toward the at least one preload element (31a).

6. The driving unit (1) according to claim 1, characterized in that, The disc component (23, 23a) containing the corresponding support surface (34, 34a) is hardened at least in the area of ​​the corresponding support surface (34, 34a).

7. The driving unit (1) according to claim 1, characterized in that, The at least one preload element (31, 31a) is hardened.

8. The driving unit (1) according to claim 4, characterized in that, The spring device (36, 36a) is formed by a helical compression spring (37, 37a) arranged circumferentially and housed in the spring windows (38, 39, 40) of the disc component (23, 23a, 24, 24a, 26, 26a), and the corresponding support surface (34, 34a) is radially disposed between the two spring windows (38, 39, 40) of the disc component (23, 23a) having the recess (33, 33a).

9. The drive unit (1) according to any one of claims 3 to 6, characterized in that, The corresponding support surfaces (34, 34a) are formed by die forming using a stamping method when manufacturing the disc components (23, 23a).

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