Spline device and electric drive system

Abstract

This utility model relates to a spline device and an electric drive system. The spline device includes: a spline shaft, each of its outer key teeth having a first side profile formed based on a first involute and a second side profile formed based on a first symmetrical involute, the first and second side profiles being symmetrical with respect to a first radial centerline and circumferentially protruding outwards; and a spline sleeve, each of its inner key teeth having a first side profile formed based on a second involute and a second side profile formed based on a second symmetrical involute, the first and second side profiles being symmetrical with respect to a second radial centerline and circumferentially protruding outwards. The first side profile of each inner key tooth tends to engage with the first side profile of the corresponding outer key tooth at the meshing line defined by the first and second involutes, and the second side profile of each inner key tooth tends to engage with the second side profile of the corresponding outer key tooth at the symmetrical meshing line defined by the first and second symmetrical involutes. This utility model achieves good centering.

Description

Technical Field

[0001] This utility model relates to the field of mechanical transmission, and specifically to spline devices and electric drive systems. Background Technology

[0002] Electric drive systems for vehicles can connect two shafts via spline connections to transmit torque. Electric drive systems require high smoothness and reliability in torque transmission; therefore, a spline connection is needed that achieves both high smoothness and reliability in torque transmission while also possessing good assemblability.

[0003] Currently, spline devices include a spline shaft and a spline sleeve. The spline shaft has multiple external key teeth, each of which may have a tooth profile formed based on an involute in its cross-section. The spline sleeve has multiple internal key teeth, each of which may have a tooth profile formed almost based on the same involute in its cross-section. Thus, the tooth profile of each internal key tooth conforms to / complements the tooth profile of the corresponding external key tooth in shape, so that the tooth profile of each internal key tooth can fit against the tooth profile of the corresponding external key tooth. However, this type of spline device in the prior art cannot achieve good alignment, and therefore cannot transmit torque smoothly and reliably. Utility Model Content

[0004] One objective of this invention is to provide an improved spline device and electric drive system, which aims to solve the problems existing in the prior art.

[0005] According to one aspect of the present invention, a spline device is provided, comprising: a spline shaft having a plurality of external key teeth, each external key tooth having a first side profile formed based on a first involute and a second side profile formed based on a first symmetrical involute about a first radial center line, wherein the first side profile and the second side profile of each external key tooth protrude outward in a circumferential direction away from the first radial center line; and a spline sleeve having a plurality of internal key teeth, each internal key tooth having a first side profile formed based on a second involute and a second side profile formed based on a second symmetrical involute about a second radial center line. The second side profile is formed by a second symmetrical involute, and the first and second side profiles of each inner key tooth protrude outward in the circumferential direction away from the second radial center line. The spline shaft is transitionally fitted with the spline sleeve such that the first side profile of each inner key tooth tends to engage with the first side profile of the corresponding outer key tooth at the meshing line defined by the first and second involutes, and the second side profile of each inner key tooth tends to engage with the second side profile of the corresponding outer key tooth at the symmetrical meshing line defined by the first and second symmetrical involutes.

[0006] Optionally, a portion of the external key tooth is formed by the area enclosed by the first side profile of each external key tooth and the line connecting its two endpoints, and another portion of the external key tooth is formed by the area enclosed by the second side profile of each external key tooth and the line connecting its two endpoints. Both portions of the external key tooth and the other portion of the external key tooth protrude outward circumferentially away from the first radial centerline. Similarly, a portion of the internal key tooth is formed by the area enclosed by the first side profile of each internal key tooth and the line connecting its two endpoints, and another portion of the internal key tooth is formed by the area enclosed by the second side profile of each internal key tooth and the line connecting its two endpoints. Both portions of the internal key tooth and the other portion of the internal key tooth protrude outward circumferentially away from the second radial centerline.

[0007] Optionally, the first involute and the first symmetrical involute are generated based on a first base circle located within the pitch circle of the spline shaft, and the second involute and the second symmetrical involute are generated by means of a second base circle located outside the pitch circle of the spline sleeve.

[0008] Optionally, the radius of the tip circle defined by the tips of the plurality of external key teeth is smaller than the radius of the root circle defined by the roots of the plurality of internal key teeth, and the radius of the root circle defined by the roots of the plurality of external key teeth is smaller than the radius of the tip circle defined by the tips of the plurality of internal key teeth, so as to ensure that the first side profile and / or the second side profile of each internal key tooth meshes with the first side profile and / or the second side profile of the corresponding external key tooth.

[0009] Optionally, the tip of each external key tooth is ground so that the tip of each external key tooth is flat; and / or the tip of each internal key tooth is ground so that the tip of each internal key tooth is flat.

[0010] Optionally, each external key tooth has a first rounded edge that smoothly transitions its first side profile to its tooth tip, and each external key tooth has a second rounded edge that smoothly transitions its second side profile to its tooth tip, and / or each internal key tooth has a first rounded edge that smoothly transitions its first side profile to its tooth tip, and each internal key tooth has a second rounded edge that smoothly transitions its second side profile to its tooth tip.

[0011] Optionally, the first rounded edge of each external key tooth is close to the line of engagement on the side connected to the first side profile of each external key tooth, and the second rounded edge of each external key tooth is close to the line of symmetry on the side connected to the second side profile of each external key tooth, and / or the first rounded edge of each internal key tooth is close to the line of engagement on the side connected to the first side profile of each internal key tooth, and the second rounded edge of each internal key tooth is close to the line of symmetry on the side connected to the second side profile of each internal key tooth.

[0012] Optionally, one axial end of the spline shaft is inserted from one axial end of the spline sleeve to achieve a transition fit between the spline shaft and the spline sleeve. At the one axial end of the spline shaft, the first side profile and / or the second side profile of each external key tooth is ground, and / or at the one axial end of the spline sleeve, the first side profile and / or the second side profile of each internal key tooth is ground.

[0013] Optionally, lubricant is filled between the splined shaft and the splined sleeve. According to another aspect of the present invention, an electric drive system is provided, comprising a motor having a motor shaft, a transmission device, and the aforementioned splined device, wherein the splined shaft of the splined device is fixed to the motor shaft, and the splined sleeve of the splined device is fixed to the transmission device, and the motor shaft is non-rotatably connected to the transmission device via the splined device.

[0014] In this invention, since each internal key tooth has a first side profile formed based on a second involute and a second side profile formed based on a second symmetrical involute in its cross-section, and the first and second side profiles of each internal key tooth protrude outwards circumferentially away from the second radial centerline, the first side profile of each internal key tooth tends to engage with the first side profile of the corresponding external key tooth at the meshing line defined by the first and second involutes, and the second side profile of each internal key tooth tends to engage with the second side profile of the corresponding external key tooth at the symmetrical meshing line defined by the first and second symmetrical involutes. Thus, the spline device achieves good centering to smoothly and reliably transmit torque. Additionally, the spline device and electric drive system in this invention are also easier to assemble and lubricate.

[0015] Other features and advantages of the present invention will become clear from the following detailed description of exemplary embodiments of the present invention with reference to the accompanying drawings. Attached Figure Description

[0016] The accompanying drawings, which form part of this specification, illustrate embodiments of the present invention and, together with the specification, serve to explain the principles of the present invention.

[0017] Figure 1 This is a simplified perspective view of an electric drive system including a spline device according to one embodiment of the present invention.

[0018] Figure 2 This is a cross-sectional view of a spline device according to one embodiment of the present invention.

[0019] Figure 3 This is a longitudinal cross-sectional view of a spline device according to one embodiment of the present invention. Detailed Implementation

[0020] Various exemplary embodiments of the present invention will now be described in detail with reference to the accompanying drawings. It should be noted that, unless otherwise specifically stated, the relative arrangement, numerical expressions, and values ​​of the components and steps set forth in these embodiments do not limit the scope of the present invention.

[0021] Technologies and equipment known to those skilled in the art may not be discussed in detail, but where appropriate, such technologies and equipment should be considered part of the specification.

[0022] In all the examples shown and discussed herein, any specific values ​​should be interpreted as merely exemplary and not as limitations. Therefore, other examples of exemplary implementations may have different values.

[0023] It should be noted that similar labels and letters in the following figures indicate similar items; therefore, once an item is defined in one figure, it does not need to be discussed further in subsequent figures.

[0024] In this article, the term "fixed" can mean that component A and component B "fixed" with component A are manufactured and installed together separately, or it can mean that component A and component B are formed as a single unit, wherein there may be intermediate components between component A and component B.

[0025] In this document, the terms “first” and “second” are used only to distinguish part A from part B and should not be construed as indicating or implying the quantity or relative importance of parts A and B.

[0026] As is well known, an electric drive system for a vehicle includes a motor, a transmission 14, and an output half-shaft fixed to the wheel hub. Power, or torque, from the motor is transmitted to the output half-shaft via the transmission 14. For example... Figure 1 As shown, the motor shaft 10 of the schematically illustrated motor can be non-rotatably connected to the schematically illustrated transmission device 14 via a splined device 12. The transmission device 14 may include a planetary gear set, so the motor shaft 10 can be non-rotatably connected to the sun gear of the planetary gear set via the splined device 12.

[0027] like Figure 2As shown, the spline device 12 provided by this utility model includes a spline shaft 16 and a spline sleeve 18 adapted to transition fit with the spline shaft 16. The spline shaft 16 can be fixed to a motor shaft 10, and the spline sleeve 18 can be fixed to a transmission device 14. The spline shaft 16 has a plurality of external key teeth 20, and an external keyway is defined between adjacent external key teeth 20. Each external key tooth 20 may have a first side profile 20a protruding toward its defined corresponding external keyway and formed based on a corresponding first involute. Each external key tooth 20 may also have a second side profile 20b protruding toward its defined corresponding external keyway and formed based on a corresponding first symmetrical involute. Alternatively, each external key tooth 20 defines a first radial centerline L1 of the corresponding external key tooth 20, and the first side profile 20a of each external key tooth 20 may protrude outward in a circumferential direction away from the first radial centerline L1 of the corresponding external key tooth 20, for example, substantially in a clockwise direction. The corresponding first symmetrical involute can be symmetrical with respect to the first radial center line L1 of the corresponding external key tooth 20, such that the second side profile 20b of each external key tooth 20 can also protrude outward in a generally counterclockwise direction from the first radial center line L1 of the corresponding external key tooth 20. The spline sleeve 18 has a plurality of internal key teeth 22, with an internal keyway defined between adjacent internal key teeth 22. Each internal key tooth 22 can have a first side profile 22a protruding into the corresponding internal keyway it defines and formed based on the corresponding second involute. Each internal key tooth 22 can also have a second side profile 22b protruding into the corresponding internal keyway it defines and formed based on the corresponding second symmetrical involute. Alternatively, each internal key tooth 22 defines a second radial center line L2 of the corresponding internal key tooth 22, and the first side profile 22a of each internal key tooth 22 can protrude outward in a generally counterclockwise direction from the second radial center line L2 of the corresponding internal key tooth 22. The corresponding second symmetrical involute can be symmetrical with respect to the second radial center line L2 of the corresponding inner key tooth 22. In this way, the second side profile 22b of each inner key tooth 22 can also be circumferentially convex outward from the second radial center line L2 of the corresponding inner key tooth 22, for example, in a basically clockwise direction.

[0028] Here, the first radial centerline L1 of the corresponding external key tooth 20 refers to a radial straight line that passes through the rotation center (or axis) of the spline shaft 16 in the cross-section and geometrically bisects the tooth thickness of the corresponding external key tooth 20. The second radial centerline L2 of the corresponding internal key tooth 22 refers to a radial straight line that passes through the rotation center (or axis) of the spline sleeve 18 in the cross-section and geometrically bisects the tooth thickness of the corresponding internal key tooth 22.

[0029] When the spline shaft 16 is transitionally assembled with the spline sleeve 18, each external key tooth 20 is received in a corresponding internal keyway and each internal key tooth 22 is received in a corresponding external keyway, such that the first side profile 22a of each internal key tooth 22 tends to engage with the first side profile 20a of the corresponding external key tooth 20 at the meshing line A1 defined by the corresponding first involute and the corresponding second involute, and such that the second side profile 22b of each internal key tooth 22 tends to engage with the second side profile 22b of the corresponding external key tooth 20 at the symmetrical meshing line A2 defined by the corresponding first symmetrical involute and the corresponding second symmetrical involute. When the transition assembly between the spline shaft 16 and the spline sleeve 18 is in the centering state (i.e., the axis of the spline shaft 16 coincides with the axis of the spline sleeve 18), the first side profile 22a of each inner key tooth 22 will engage with the first side profile 20a of the corresponding outer key tooth 20 at the meshing line A1, and / or the second side profile 22b of each inner key tooth 22 will engage with the second side profile 20b of the corresponding outer key tooth 20 at the symmetrical meshing line A2.

[0030] When the transitional assembly between the spline shaft 16 and the spline sleeve 18 occurs, for example, due to alignment errors caused by operating conditions, the first side profile 22a of each inner key tooth 22 will deviate from the meshing line A1 and engage with the first side profile 20a of the corresponding outer key tooth 20, and / or the second side profile 22b of each inner key tooth 22 will deviate from the symmetrical meshing line A2 and engage with the second side profile 20b of the corresponding outer key tooth 20. This deviation will generate a torque due to the characteristics of the involute, causing the transitional assembly between the spline shaft 16 and the spline sleeve 18 to return to the alignment state, thereby guiding the first side profile 22a of each inner key tooth 22 back to engage with the first side profile 20a of the corresponding outer key tooth 20 at the meshing line A1, and / or guiding the second side profile 22b of each inner key tooth 22 back to engage with the second side profile 20b of the corresponding outer key tooth 20 at the symmetrical meshing line A2. In this way, the torque from the motor shaft 10 of the motor can be smoothly transmitted to the transmission device 14 by means of the spline device 12. Therefore, the word "tends toward" is used here to represent this tendency of movement of the spline device 12.

[0031] To reiterate, the region enclosed by the first side profile 20a of each external key tooth 20 and the line connecting its two endpoints forms a portion of the corresponding external key tooth 20. This portion of the corresponding external key tooth 20 is located on one side of the first radial center line L1 of the corresponding external key tooth 20 and protrudes (or bulges) outward circumferentially away from the first radial center line L1 of the corresponding external key tooth 20. Similarly, the region enclosed by the second side profile 20b of each external key tooth 20 and the line connecting its two endpoints forms another portion of the corresponding external key tooth 20. This other portion of the corresponding external key tooth 20 is located on the other side of the first radial center line L1 of the corresponding external key tooth 20 and protrudes (or bulges) outward circumferentially away from the first radial center line L1 of the corresponding external key tooth 20, opposite to the circumferentially protruding (or bulging) portion of the corresponding external key tooth 20.

[0032] The region enclosed by the first side profile 22a of each inner key tooth 22 and the line connecting its two endpoints forms a portion of the corresponding inner key tooth 22. This portion of the corresponding inner key tooth 22 is located on one side of the second radial center line L2 of the corresponding inner key tooth 22 and protrudes (or bulges) circumferentially outward from the second radial center line L2 of the corresponding inner key tooth 22. Similarly, the region enclosed by the second side profile 22b of each inner key tooth 22 and the line connecting its two endpoints forms another portion of the corresponding inner key tooth 22. This other portion of the corresponding inner key tooth 22 is located on the other side of the second radial center line L2 of the corresponding inner key tooth 22 and protrudes (or bulges) circumferentially outward from the second radial center line L2 of the corresponding inner key tooth 22, opposite to the circumferentially outward portion of the corresponding inner key tooth 22. In contrast, in the prior art, the area enclosed by the first side profile of each inner key tooth and the line connecting its two endpoints does not form part of the corresponding inner key tooth, and the area enclosed by the second side profile of each inner key tooth and the line connecting its two endpoints does not form another part of the corresponding inner key tooth, because the first and second side profiles of each inner key tooth are circumferentially concave inward relative to each other.

[0033] Here, the multiple first involutes and multiple first symmetrical involutes corresponding to the multiple external key teeth 20 of the spline shaft 16 are all generated based on a unique first base circle. The multiple starting points corresponding to the multiple first involutes and the multiple starting points corresponding to the multiple first symmetrical involutes are distributed at intervals on the periphery of the first base circle, and the first base circle is located within the pitch circle of the spline shaft 16. In contrast, the multiple second involutes and multiple second symmetrical involutes corresponding to the multiple inner key teeth 22 of the spline sleeve 18 are generated based on multiple second base circles. For example, the second involute and second symmetrical involute of one inner key tooth 22 are generated based on one second base circle, and the second involute and second symmetrical involute of another inner key tooth 22 adjacent to one inner key tooth 22 are generated based on another second base circle. The two second base circles are the same size, but their centers are spaced apart by a certain angle, so that the radial center line L2 of the corresponding inner key tooth 22 passes through the center of each second base circle. Furthermore, all the multiple second base circles are located outside the pitch circle of the spline sleeve 18. Thus, it is again evident that the design of the spline sleeve 18 differs from the prior art.

[0034] Continue to refer to Figure 2 The radius of the tip circle defined by the tooth tip 20c of the plurality of external key teeth 20 is smaller than the radius of the root circle defined by the tooth root 22d of the plurality of internal key teeth 22, and the radius of the root circle defined by the tooth root 20d of the plurality of external key teeth 20 is smaller than the radius of the tip circle defined by the tooth tip 22c of the plurality of internal key teeth 22. This ensures that when each external key tooth 20 is received in the corresponding internal keyway and each internal key tooth 22 is received in the corresponding external keyway, the first side profile 22a and / or the second side profile 22b of each internal key tooth 22 meshes with the first side profile 20a and / or the second side profile 20b of the corresponding external key tooth 20. In other words, this ensures that the spline shaft 16 and the spline sleeve 18 are engaged and aligned by the tooth profile meshing.

[0035] For example, the tip 20c of each external key tooth 20 can be ground so that the tip 20c of each external key tooth 20 is flat, and the radius of the circle of the tip 20c of the plurality of external key teeth 20 is smaller than the radius of the root 22d of the plurality of internal key teeth 22.

[0036] Alternatively or supplementarily, the tooth tip 22c of each inner key tooth 22 may be ground so that the tooth tip 22c of each inner key tooth 22 is flat, and the radius of the circle of the tooth root 20d of the plurality of outer key teeth 20 is smaller than the radius of the circle of the tooth tip 22c of the plurality of inner key teeth 22.

[0037] Each external key tooth 20 has a first rounded edge 20e that smoothly transitions its first side profile 20a to its tooth tip 20c, and each external key tooth 20 has a second rounded edge 20f that smoothly transitions its second side profile 20b to its tooth tip 20c, to eliminate sharp corners caused by grinding of the tooth tip 20c of each external key tooth 20.

[0038] Alternatively or supplementally, each inner key tooth 22 has a first rounded edge 22e that smoothly transitions its first side profile 22a to its tooth tip 22c, and each inner key tooth 22 has a second rounded edge 22f that smoothly transitions its second side profile 22b to its tooth tip, to eliminate the sharp corners caused by grinding the tooth tip 22c of each inner key tooth 22.

[0039] Optionally, the first rounded edge 20e of each external key tooth 20 may be close to the line of engagement A1 on the side connected to the first side profile 20a of each external key tooth 20, and the second rounded edge 20f of each external key tooth 20 may be close to the line of symmetry A2 on the side connected to the second side profile 20b of each external key tooth 20. Alternatively or supplementarily, the first rounded edge 22e of each internal key tooth 22 may be close to the line of engagement A1 on the side connected to the first side profile 22a of each internal key tooth 22, and the second rounded edge 22f of each internal key tooth 22 may be close to the line of symmetry A2 on the side connected to the second side profile 22b of each internal key tooth 22. This facilitates the machining of the first rounded edge 22e and the second rounded edge of each external key tooth 20, as well as the first rounded edge 22e and the second rounded edge of each internal key tooth 22.

[0040] Optionally, such as Figure 3 As shown, each external key tooth 20 is received into a corresponding internal keyway from an axial end 18a of a spline sleeve 18 via an axial end 16a of a spline shaft 16. At the axial end 16a of the spline shaft 16, the first side profile 20a and / or the second side profile 20b of each external key tooth 20 are ground to reduce the tooth thickness of each external key tooth 20 at the axial end 16a of the spline shaft 16, and / or at the axial end 18a of the spline sleeve 18, the first side profile 22a and / or the second side profile 22b of each internal key tooth 22 are ground to reduce the tooth thickness of each internal key tooth 22 at the axial end 18a of the spline sleeve 18. Thus, during the transition assembly of the spline shaft 16 to the spline sleeve 18, the axial end 16a of the spline shaft 16 can be more easily inserted into the axial end 18a of the spline sleeve 18.

[0041] Optionally, lubricant is filled between the spline shaft 16 and the spline sleeve 18. When the spline shaft 16 is transitionally fitted to the spline sleeve 18, the engagement of the first side profile 22a of each inner key tooth 22 with the first side profile 20a of the corresponding outer key tooth 20 can provide a relatively larger clearance to accommodate the lubricant.

[0042] While some specific embodiments of the present invention have been described in detail by way of examples, those skilled in the art should understand that the above examples are for illustrative purposes only and are not intended to limit the scope of the present invention. Those skilled in the art should understand that modifications can be made to the above embodiments without departing from the scope and spirit of the present invention. The scope of the present invention is defined by the appended claims.

Claims

1. A spline device (12), characterized in that, include: A spline shaft (16) having a plurality of external key teeth (20), each external key tooth (20) having, in cross-section, a first side profile (20a) formed based on a first involute and a second side profile (20b) formed based on a first symmetrical involute symmetrical about a first radial centerline (L1), and the first side profile (20a) and the second side profile (20b) of each external key tooth (20) circumferentially protruding outward from the first radial centerline (L1); and Spline sleeve (18) having a plurality of internal key teeth (22), each internal key tooth (22) having a first side profile (22a) formed based on a second involute and a second side profile (22b) formed based on a second symmetrical involute symmetrical about the second radial centerline (L2) in cross-section, and the first side profile (22a) and the second side profile (22b) of each internal key tooth (22) protruding outward in the circumferential direction away from the second radial centerline (L2). The spline shaft (16) and the spline sleeve (18) are transitionally fitted such that the first side profile (22a) of each inner key tooth (22) tends to engage with the first side profile (20a) of the corresponding outer key tooth (20) at the meshing line (A1) defined by the first involute and the second involute, and the second side profile (22b) of each inner key tooth (22) tends to engage with the second side profile (20b) of the corresponding outer key tooth (20) at the symmetrical meshing line (A2) defined by the first symmetrical involute and the second symmetrical involute.

2. The spline device (12) according to claim 1, characterized in that, A portion of the outer key tooth (20) is formed by the area enclosed by the first side profile (20a) of each outer key tooth (20) and the line connecting its two endpoints. Another portion of the outer key tooth (20) is formed by the area enclosed by the second side profile (20b) of each outer key tooth (20) and the line connecting its two endpoints. Both the portion and the portion of the outer key tooth (20) protrude outward circumferentially away from the first radial centerline (L1). A portion of the inner key tooth (22) is formed by the area enclosed by the first side profile (22a) of each inner key tooth (22) and the line connecting its two endpoints. Another portion of the inner key tooth (22) is formed by the area enclosed by the second side profile (22b) of each inner key tooth (22) and the line connecting its two endpoints. Both the portion and the portion of the inner key tooth (22) protrude outward circumferentially away from the second radial centerline (L2).

3. The spline device (12) according to claim 1, characterized in that, The first involute and the first symmetrical involute are generated based on a first base circle located within the pitch circle of the spline shaft (16), and the second involute and the second symmetrical involute are generated based on a second base circle located outside the pitch circle of the spline sleeve (18).

4. The spline device (12) according to any one of claims 1 to 3, characterized in that, The radius of the tip circle defined by the tooth tip (20c) of the plurality of external key teeth (20) is smaller than the radius of the root circle defined by the tooth root (22d) of the plurality of internal key teeth (22), and the radius of the root circle defined by the tooth root (20d) of the plurality of external key teeth (20) is smaller than the radius of the tip circle defined by the tooth tip (22c) of the plurality of internal key teeth (22), so as to ensure that the first side profile (22a) and / or the second side profile (22b) of each internal key tooth (22) meshes with the first side profile (20a) and / or the second side profile (20b) of the corresponding external key tooth (20).

5. The spline device (12) according to claim 4, characterized in that, The tooth tip (20c) of each external key tooth (20) is ground so that the tooth tip (20c) of each external key tooth (20) is flat; and / or The tip (22c) of each internal key tooth (22) is ground so that the tip (22c) of each internal key tooth (22) is flat.

6. The spline device (12) according to claim 5, characterized in that, Each external key tooth (20) has a first rounded edge (20e) that smoothly transitions its first side profile (20a) to its tooth tip (20c), and each external key tooth (20) has a second rounded edge (20f) that smoothly transitions its second side profile (20b) to its tooth tip (20c), and / or Each inner key tooth (22) has a first rounded edge (22e) that smoothly transitions its first side profile (22a) to its tooth tip (22c), and each inner key tooth (22) has a second rounded edge (22f) that smoothly transitions its second side profile (22b) to its tooth tip (22c).

7. The spline device (12) according to claim 6, characterized in that, The first rounded edge (20e) of each external key tooth (20) is close to the line of engagement (A1) on the side connected to the first side profile (20a) of each external key tooth (20), and the second rounded edge (20f) of each external key tooth (20) is close to the line of symmetry (A2) on the side connected to the second side profile (20b) of each external key tooth (20), and / or The first rounded edge (22e) of each inner key tooth (22) is close to the line of engagement (A1) on the side connected to the first side profile (22a) of each inner key tooth (22), and the second rounded edge (22f) of each inner key tooth (22) is close to the line of symmetry (A2) on the side connected to the second side profile (22b) of each inner key tooth (22).

8. The spline device (12) according to claim 7, characterized in that, One axial end (16a) of the spline shaft (16) is inserted from one axial end (18a) of the spline sleeve (18) such that the spline shaft (16) transitions into the spline sleeve (18). At the one axial end (16a) of the spline shaft (16), the first side profile (20a) and / or the second side profile (20b) of each external key tooth (20) is ground, and / or at the one axial end (18a) of the spline sleeve (18), the first side profile (22a) and / or the second side profile (22b) of each internal key tooth (22) is ground.

9. The spline device (12) according to any one of claims 1 to 3, characterized in that, Lubricant is filled between the spline shaft (16) and the spline sleeve (18).

10. An electric drive system, characterized in that, The device includes a motor having a motor shaft (10), a transmission device (14), and a spline device (12) according to any one of claims 1 to 9, wherein the spline shaft (16) of the spline device (12) is fixed to the motor shaft (10), and the spline sleeve (18) of the spline device (12) is fixed to the transmission device (14), and the motor shaft (10) is non-rotatably connected to the transmission device (14) via the spline device (12).

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