Electric drive device for motor vehicle

Abstract

The invention relates to an electric drive (1) for a motor vehicle, comprising: an electric machine (2) having a rotor (3); a planetary gear stage (13) comprising a sun gear (11), a planet carrier (8) with planet gears (10) and a ring gear (12); a switchable one-way clutch (20) comprising a first clutch half (21), a second clutch half (22), a switching member (25) and an actuator (26), the first clutch half (21) being connected to the housing (5) in a rotationally fixed manner. The electric drive is characterized in that the second clutch half (22) is connected in a rotationally fixed manner to the ring gear (12), and in that the engagement element (24) is connected in a rotationally fixed manner to the ring gear (12) and in a rotationally fixed manner to the second clutch half (22) and is arranged radially with respect to the rotational axis (A) of the planetary gear stage (13) between a sun gear tooth row of the sun gear (11) and a ring gear tooth row of the ring gear (12).

Description

Field of the Invention

[0001] The present invention relates to an electric drive device for a motor vehicle of the type described in the preamble of claim 1. Background Art

[0002] DE 10 2019 114 139 B3 describes a prior art in the form of a motor vehicle transmission for engaging an electric motor to a drive train. Here, a planetary gear stage is provided between the electric motor and the drive train, which includes a central gear, a planetary gear carrier with planetary gears, and a ring gear. Additionally, a switchable one-way clutch is provided in the vehicle transmission, which can switchably engage the central gear to a reference member, especially a fixed housing, by means of two clutch halves, i.e., selectively enable the central gear to rotate freely and / or be locked relative to the housing. The document DE 10 2015 110 565 A1 of the same type shows a very similar electric drive device, where a connecting member is also provided, which is non-rotatably connected to the ring gear and non-rotatably connected to one of the clutch halves. The connecting member itself has a cylindrical portion arranged coaxially with the rotational axis of the planetary gear stage. Summary of the Invention

[0003] The object of the present invention is to provide an electric drive device for a motor vehicle that further improves the above-mentioned prior art structure by simplifying the structure, thereby saving structural space, components, and costs.

[0004] According to the present invention, the object is achieved by an electric drive device for a motor vehicle having the features of claim 1, especially the features in the characterizing part of claim 1. Advantageous designs and improvements of the electric drive device according to the present invention result from the dependent claims subordinate to claim 1.

[0005] The design of the electric drive device for a motor vehicle is specified in a manner known per se, such that the second clutch half of the switchable one-way clutch is non-rotatably connected to the ring gear, and a connecting member that forms a non-rotatable connection with both the ring gear and the second clutch half is arranged radially between the central gear teeth of the central gear and the ring gear teeth of the ring gear with respect to the rotational axis of the planetary gear stage.

[0006] In the present invention, the so-called "non-rotatable connection" refers to any connection method that ensures coaxial non-rotatably connected components rotate around the same rotational axis with the same angular velocity.

[0007] This switchable one-way clutch arranged between the ring gear and the housing is structurally advantageous here and enables an easily installable and very compact structure of the electric drive device. Therefore, the connecting member is arranged at a radial position between the central gear teeth and the ring gear teeth, thereby ensuring a very compact structure of the electric drive device in the radial direction.

[0008] The coupling element also has, in a manner known per se, a cylindrical part arranged coaxially with the axis of rotation of the planetary gear stage.

[0009] According to the invention, the cylindrical part is arranged radially with respect to the axis of rotation in the region of the planet pins provided on the planet carrier of the gear stage. The cylindrical part is thus radially adjacent to the planet pins of the planet carrier, on which the planet gears are respectively arranged. This ensures a compact structure, in which the cylindrical part is designed to be nested within the switchable clutch, and particularly preferably, the corresponding guide parts of the axial guide ring and the disk assembly are also arranged axially inside the cylindrical part and overlap with it. A very compact structure can thus be achieved.

[0010] The invention also provides that the ring gear is designed without a rolling bearing that independently directly supports the ring gear (i.e., without a transmission element arranged therebetween), and is supported only by an axial guide ring in two axial directions. The inventor utilizes here the fact that in the case where two shafts of the planetary gear mechanism are radially supported ("radially" always with respect to the central axis of the planetary gear mechanism), the third shaft does not require radial support. Thus, the rolling bearing for the ring gear (which is the component with the relatively largest diameter in the planetary gear mechanism) can be omitted. This saves the costs, structural space, and weight required for a relatively large rolling bearing.

[0011] In this case, the ring gear itself is centered by the shafts of the other two components of the planetary gear mechanism, namely the planet carrier and the central gear. The axial guide ring of the invention then only serves to prevent significant axial displacement of the ring gear. Since the ring gear itself does not bear axial forces (this is because it is centered by these other components in the unengaged state and is fixed relative to the housing in the engaged state), it is sufficient to achieve a very simple axial guidance with the axial guide ring, and for this purpose, strict requirements for the inner support or mechanical stability of the axial guide ring are not required.

[0012] Regarding the omission of the rolling bearing, for example: the motor rotor shaft is directly roll-supported relative to the housing and carries the central gear, so the central gear is also supported accordingly. Then, the other component is the planet carrier, which is also directly roll-supported relative to the housing. Of course, this structure can be arranged conversely, i.e., the central gear is independently directly roll-supported relative to the housing, while the planet carrier is indirectly roll-supported relative to the housing through the rotor shaft. In both cases, the ring gear is indirectly supported relative to the housing by cooperating with the planet gears located on the planet carrier and the central gear, and by the supports of both the central gear and the planet carrier, so the ring gear itself does not require an independent direct support relative to the housing.

[0013] The drive can still be disengaged via a switchable one-way clutch, thereby avoiding traction losses, for example when the vehicle is driven actively only by at least one other axle.

[0014] The cylindrical part transfers the connection possibility to the axial direction and can be connected to the disc-shaped assembly according to another very advantageous design, so that the cylindrical part is connected to the ring gear in a rotation-resistant manner and to the disc-shaped assembly that itself forms a rotation-resistant connection with the ring gear.

[0015] Preferably, the motor rotor can be arranged coaxially with the planetary gear stage here, and the disc-shaped assembly is arranged axially on the side of the planetary gear stage facing away from the rotor. The cylindrical part is then axially located on the side of the disc-shaped assembly facing away from the planetary gear stage, so that the rotor, the planetary gear stage, the disc-shaped assembly and the cylindrical part are arranged axially in this order successively.

[0016] According to an extremely advantageous design, it can now also be provided that the axial guide ring has a U-shaped cross-sectional profile that is open radially outwards. The axial guide ring can thus axially guide, for example, the ring gear itself or a disc connected to the ring gear (such as in the form of a section of the disc-shaped assembly or as a section of the disc-shaped assembly), thereby preventing axial displacement of the ring gear. In other words, the axial guide ring has a groove that is open on the radially outwards side of the axial guide ring. In this way, a U-shaped cross-sectional profile is presented in the central section of the electric drive device, where in the central section, the U-shaped cross-sectional profile is open upwards above the axis of rotation. The disc-shaped assembly is advantageously inserted into the groove from the radially outer side.

[0017] Here, according to another very advantageous design of the electric drive device according to the invention, the axial guide ring can be arranged radially inside the one-way clutch and axially overlap with it. The "radially inner side" here still refers to the central axis of rotation of the planetary gear mechanism, indicating that the axial guide ring is located at a smaller diameter position than the switchable one-way clutch. "Axial overlap" also refers to this axis, indicating that the two components are located in the same plane perpendicular to the axis of rotation of the planetary gear stage in the axial direction, or the two components at least intersect with a common plane perpendicular to the axis of rotation.

[0018] Another very advantageous design can also provide that the disc-shaped assembly has a guiding part designed to cooperate with the axial guide ring. This guiding part of the disc-shaped assembly can thus be used to axially guide the ring gear through the axial guide ring in the above-mentioned manner. In this preferred design where the axial guide ring is arranged radially inside the one-way clutch and axially overlaps with it, the guiding part of the disc-shaped assembly is therefore arranged in this area. The guiding part preferably has two axially parallel side surfaces, and these two side surfaces cooperate with a radially outwards open guide ring equipped with axially parallel arms and having a U-shaped cross-sectional profile. The guiding part is advantageously inserted into the groove of the axial guide ring.

[0019] Particularly advantageously, the axial guide ring is arranged radially on the inner side of the cylindrical part.

[0020] In a very advantageous design of the electric drive device for a motor vehicle according to the invention, the switchable one-way clutch can have a switching disk as the switching element, wherein the actuator is designed to cause the switching disk to perform a rotational movement. The switchable one-way clutch can thus in particular be configured according to the prior art solution described in DE 10 2019 114 139 B3 mentioned in the preamble. Here, by means of the switching element, it is possible to provide not only a one-way clutch that locks in both the traction direction and the inertia direction, but also to lock or release the connection in these two rotational directions.

[0021] The structure of the switching disk can preferably also be designed to be switchable in only one direction, namely the traction reverse direction (equivalent to the inertia forward direction). In this way, reverse driving and forward energy recovery can be achieved. The switchability in the traction forward direction (equivalent to the inertia reverse direction) is not necessary per se. Thus, although the wheel can be separated from the output device during high-speed reverse driving (i.e., in the reverse inertia mode), this situation hardly occurs in practice, so the structure can be correspondingly simplified. The advantage of this design is that only one set of movable pawls (for one direction) and one switching disk are required, and only one actuator is also required for the switching disk.

[0022] Another very advantageous design of the electric drive device can also provide that the actuator of the switchable one-way clutch is arranged in the housing. Such an actuator arranged in the housing is easily accessible, for example, when maintenance and other operations are required. According to a very advantageous improvement, the actuator can in particular be arranged radially outside the clutch half, or in principle as an alternative, it can also be arranged axially overlapping at least one of the clutch halves. This also saves structural space axially, and due to the radially outer actuator, a simple and easily maintainable switching disk operation can be achieved as required. Description of the Drawings

[0023] Other advantageous designs of the electric drive device according to the invention also result from the embodiments described in detail below with reference to the figures.

[0024] The sole figure shows a sectional schematic view of the part of the electric drive device according to the invention. Detailed Description of the Embodiment

[0025] Figure 1Shows a partial view of the electric drive device 1. This partial view shows the part above the rotational axis A, which also correspondingly defines the axial direction a and the radial direction r. The electric machine 2 with the rotor 3 rotates about its rotational axis A. In this embodiment, the electric machine 2 is designed as an axial-flux electric machine here. The rotor 3 (only half of it located on the right side inside the electric machine 2 or on the right side of the stator 30 is correspondingly shown here) is supported relative to the housing 5 by the rotor bearing 6. In this embodiment, the rotor is non-rotatably connected to the multi-piece rotor shaft 4. The rotor shaft 4 is indirectly supported by the rotor bearing 6 of the rotor 3 (preferably designed as a miter / angle contact ball bearing), and is also supported on the housing by the needle bearing 28.

[0026] At the distal end of the axial direction a of the electric machine 2, an output device 7 leading to a motor vehicle wheel or an axle reducer (such as a differential) is shown. The output device 7 is non-rotatably connected to the planet carrier 8 (as the output member of the planetary gear stage 13) here by means of the output shaft 18 and the spline shaft tooth row marked with 19.

[0027] The gist of the present invention is that the planet carrier 8 of the planetary gear stage 13 is engaged or can be engaged to the output device 7 in such a way that the torque is output from the planetary gear stage through the planet carrier 8. The central gear 11 of the planetary gear stage 13 is engaged or can be engaged to the rotor 3 in such a way that the torque generated by the rotor 3 can be input into the planetary gear stage at the central gear 11.

[0028] The planet carrier 8 has planet gear pins 9 protruding towards the electric machine 2 in the axial direction. These planet gears 10 (one of which can be seen in the figure) are supported on the planet gear pins 9 by the planet gear bearing device 33 (in the form of two angular contact ball bearings 33.1, 33.2 here). The central gear 11 meshes with the planet gears 10 on the radially inner side, and the central gear is formed by the tooth row of the rotor shaft 4. The ring gear 12 supplements this structure into a planetary gear stage 13 for torque conversion between the rotor 3 and the output device 7.

[0029] In this case, the ring gear 12 is not supported by its own / independent rolling bearing, but is supported on the housing 5 by the support of the planet gears 10 or the planet carrier 8, by means of two planet carrier bearings marked with 14.1 and 14.2. In order to ensure that the ring gear 12 does not move significantly in the axial direction a, in the embodiment shown here, an axial guide ring 15 is provided on the housing 5, which has a U-shaped cross-sectional profile, so that both arms protrude radially outwards, and the U-shaped profile is open radially outwards. The guide part 16 of the disc-shaped protruding part designed as the disc-shaped assembly 17 protrudes into the U-shaped profile of the axial guide ring 15, which is not used for support, but only plays a guiding and supporting role, because axial support is not required here. The disc-shaped assembly 17 is non-rotatably directly connected to the ring gear 12, and thus rotates at the same angular velocity as the ring gear 12.

[0030] In Figure 1 the illustration shown in Figure 1 , the electric drive device 1 further includes a switchable one-way clutch 20, which includes a first clutch half 21 and a second clutch half 22. The first clutch half 21 is designed as a ring with an external tooth row and is connected by a one-way clutch carrier 23 with a radially inward tooth row. The one-way clutch carrier 23 itself is non-rotatably connected to the housing 5. The second clutch half 22 is designed as an annular disk with an internal tooth row, which is mounted on the engagement member 24 and is non-rotatably connected thereto by means of said tooth row.

[0031] The engagement member 24 has a cylindrical portion 27 here and is non-rotatably connected to the disk-shaped assembly 17, so that the second clutch half 22 is indirectly non-rotatably connected to the ring gear 12 via the engagement member 24 and the disk-shaped assembly 17. The switchable one-way clutch 16 thus acts on the ring gear 12, so that the ring gear can be released, or depending on the switching position of the switching disk 25 used as a switching element, the connection between the ring gear 12 and the housing 5 can be locked or released in inertial or traction mode. The switching disk 25 can be rotated by an actuator 26, wherein the actuator 26 is in effective connection with the switching disk 25 via a connecting mechanism shown by a dashed line and is located inside the housing 5 and radially outside the switchable one-way clutch 20.

[0032] Advantageously, the second clutch half 22 is arranged to be axially movable relative to the engagement member 24 and axially movable relative to the cylindrical portion 27.

[0033] Advantageously, the axially movable second clutch half 22 is axially arranged on the side of the first clutch half 21 facing away from the planetary gear 10.

[0034] Advantageously, the axial guide ring 15 is radially arranged inside the cylindrical portion 27.

[0035] The cylindrical portion 27 is advantageously radially arranged inside the one-way clutch 20.

[0036] Particularly advantageously, the axial guide ring 15 is radially arranged in the region of at least one of the two planetary gear carrier bearings 14.2, 14.2. Advantageously, the axial guide ring 15 is arranged to radially overlap with at least one of the two planetary gear carrier bearings 14.2, 14.2.

[0037] Even more particularly preferably, the axial guide ring axially overlaps with the second clutch half 22.

[0038] For structural reasons, the switchable one-way clutch 16 is arranged at the position shown between the ring gear 12 and the housing 5 such that the first clutch half 21 is non-rotatably connected to the housing 5. When the second clutch half 22 is separated from the first clutch half 21 and thus from the housing 5, the switching disk 25 presses the corresponding pawls in accordance with the structure of DE 10 2019 114 139 B3. This occurs in the inertial forward mode, i.e., when the inertial forward side is deactivated. Here, a non-switchable one-way clutch function can be provided in the one-way clutch 16, especially between the two clutch halves 21, 22. The switching disk 25 is then located between the second clutch half 22 and the housing 5 (or the one-way clutch carrier 23 fixedly connected to the housing), and releases or presses the spring-loaded pawls according to the switching position, such that the pawls act in the opposite rotational direction of the one-way clutch function between the clutch halves 21, 22 according to the switching position. There are thus two switching states: one is the one-way clutch state, and the other is the fully engaged braking state (where both directions are locked).

[0039] Here, although the planet carrier 8 still rotates with the driven wheels of the motor vehicle, the ring gear 12 itself is in a free state relative to the housing 5, so the central gear 11 is not actually driven, which results in only minor frictional losses between the planet gears 10 and the central gear 11. Although the arrangement of the one-way clutch 16 is structurally advantageous, it can still achieve its function with an acceptable level of structural efficiency.

[0040] This structure does not provide an independent support for the ring gear 12, but only achieves axial guidance by means of the axial guide ring 15, and through the nested arrangement of the components (especially by means of the disk-shaped assembly 17, the cylindrical part of the engagement member 24, and the guide part 16), a structure that is both axially and radially compact for the electric drive device 1 is achieved.

[0041] List of reference numerals

[0042] 1 Electric drive device

[0043] 2 Electric motor

[0044] 3 Rotor

[0045] 4 Rotor shaft

[0046] 5 Housing

[0047] 6 Rotor bearing

[0048] 7 Output device

[0049] 8 Planet carrier

[0050] 9 Planet pin

[0051] 10 Planet gear

[0052] 11 Central gear

[0053] 12 Ring gear

[0054] 13 Planetary gear stage

[0055] 14.1, 14.2 Planet carrier bearings

[0056] 15 Axial guide ring

[0057] 16 Guide portion

[0058] 17 Disc assembly

[0059] 18 Output shaft

[0060] 19 Spline shaft teeth

[0061] 20 Switchable one-way clutch

[0062] 21 First clutch half

[0063] 22 Second clutch half

[0064] 23 One-way clutch carrier

[0065] 24 Engagement member

[0066] 25 Switching disc

[0067] 26 Actuator

[0068] 27 Cylindrical portion (of engagement member 24)

[0069] 28 Needle bearing

[0070] 30 Stator

[0071] A Axis of rotation

[0072] a Axial direction

[0073] r Radial direction

Claims

1. An electric drive device (1) for a motor vehicle, which comprises: - an electric motor (2) having a rotor (3); - a planetary gear stage (13) comprising a central gear (11), a planet carrier (8) with planet gears (10) and a ring gear (12); - a switchable one-way clutch (20), said switchable one-way clutch comprising a first clutch half (21), a second clutch half (22), a switching element (25) and an actuator (26), wherein the first clutch half (21) is non-rotatably connected to the housing (5), wherein the second clutch half (22) is non-rotatably connected to the ring gear (12), wherein an engagement element (24) is non-rotatably connected to the ring gear (12) and non-rotatably connected to the second clutch half (22), and is arranged radially between the central gear teeth of the central gear (11) and the ring gear teeth of the ring gear (12) with respect to the axis of rotation (A) of the planetary gear stage (13), wherein the engagement element (24) has a cylindrical part (27) arranged coaxially with the axis of rotation (A) of the planetary gear stage (13), characterized in that the cylindrical part (27) is arranged radially within the region of the planet pins (9) of the planet carrier (8) of the planetary gear stage (13) that carry the planet gears (10) with respect to the axis of rotation (A) of the planetary gear stage (13), wherein an axial guide ring (15) is provided, which is designed to support the ring gear (12) in two axial directions (a), wherein the ring gear (12) is designed without a rolling bearing directly supporting the ring gear.

2. The electric drive device (1) according to claim 1, characterized in that a disk-shaped assembly (17) is provided for non-rotatably connecting the cylindrical part (27) to the ring gear (12).

3. The electric drive device (1) according to claim 2, characterized in that the rotor (3) is arranged coaxially with the planetary gear stage (13), and the disk-shaped assembly (17) is arranged axially on the side of the planetary gear stage (13) facing away from the rotor (3), wherein the cylindrical part (27) is arranged axially on the side of the disk-shaped assembly (17) facing away from the planetary gear stage (13).

4. The electric drive device (1) according to one of the preceding claims, characterized in that the axial guide ring (15) has a U-shaped cross-sectional profile that is open radially outwards.

5. The electric drive device (1) according to one of the preceding claims, characterized in that the axial guide ring (15) is arranged radially inside the one-way clutch (20) and overlaps the one-way clutch axially.

6. The electric drive device (1) according to claim 2, characterized in that the disk-shaped assembly (17) has a guiding part (16) designed to cooperate with the axial guide ring (15).

7. The electric drive device (1) according to one of the preceding claims, characterized in that the axial guide ring (15) is arranged radially inside the cylindrical part (27).

8. The electric drive device (1) according to one of the preceding claims, characterized in that, the second clutch half (22) is axially arranged on the side of the first clutch half facing away from the planetary gear (10).

9. The electric drive device (1) according to one of the preceding claims, characterized in that, the switchable one-way clutch (20) has a switching disk as a switching element (25), wherein the actuator (26) is designed to cause the switching disk to perform a rotational movement.

10. The electric drive device (1) according to one of the preceding claims, characterized in that, the actuator (26) of the switchable one-way clutch (20) is arranged in the housing (5).

11. The electric drive device (1) according to one of the preceding claims, characterized in that, the actuator (26) of the switchable one-way clutch (20) is arranged radially outside the clutch halves (21, 22) and / or is arranged axially overlapping at least one of the clutch halves (21, 22).

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