Device for the rotationally fixed connection of a shaft with a gear arranged thereon

Abstract

A device (100) is proposed for the rotationally fixed connection of a shaft (3) to a gear (4) arranged thereon via a spline (9). The spline (9) comprises an internal toothing (10) of the gear (4) and an external tooth profile (11) of the shaft (3) meshing therewith. In order to limit load peaks to permissible values, at least one tip clearance (c9A) of the spline (9A) is greater than 0.5 times the module of the spline (9A) and less than 10 times the module of the spline (9A).

Description

[0001] The invention relates to a device for the rotationally fixed connection of a shaft to a gear arranged thereon via a spline according to the type defined in more detail in the preamble of patent claim 1.

[0002] Devices for the rotationally fixed connection of shafts with gears arranged on them via shaft-hub connections in drive trains are exposed to unwanted load peaks in various situations due to a wide variety of factors, which place unnecessary mechanical stress on the components involved. A common example of such load peaks is a conventional parking lock mechanism, which briefly experiences high torque peaks on a shaft during actuation. The resulting dynamic loads are significantly higher than the static loads and require an unnecessarily large and robust design of all components involved in the parking lock mechanism, particularly with regard to operational strength and service life. However, even in the area of ​​conventional gears, high starting forces and load peaks can act on the gear teeth during operation of a vehicle transmission.

[0003] DE 10 2020 207 340 A1 discloses a parking lock device for a vehicle and a method for producing a parking lock device for a vehicle. The transmission of a locking torque to the components of the parking lock device can be dampened, resulting in a more cost-effective, lighter, and more compact parking lock device and an electric drive unit. The parking lock device can be installed in such an electric drive unit, for example, an electric drive axle. For this purpose, the parking lock device comprises at least one damping device arranged between a vane region and a stop in the azimuthal intermediate region. Additionally, a locking pawl is provided, which can be engaged in a recess and by means of which a rotational movement of a ratchet wheel can be locked.When the ratchet wheel is locked, the transmission of torque from the stop to the wing area can be at least partially absorbed by the damping device.

[0004] However, the parking lock device is structurally complex and causes undesirably high manufacturing costs.

[0005] The object of the present invention is to provide a structurally simple and cost-effective device for the rotationally fixed connection of a shaft to a gear arranged thereon via a spline, with which load peaks can be dampened in a simple manner.

[0006] According to the invention, this object is achieved by a device having the features of patent claim 1.

[0007] A device is proposed for the rotationally fixed connection of a shaft to a gear arranged thereon via a spline, which comprises an internal toothing of the gear and an external tooth profile of the shaft engaging therewith.

[0008] According to the invention, the elasticity of the spline is designed to limit load peaks to permissible values ​​in the area of ​​the internal toothing of the gear and / or in the area of ​​the external tooth profile of the shaft. For this purpose, at least one tip clearance of the spline is greater than 0.5 times the module of the spline and less than 10 times the module of the spline.

[0009] The tip clearance of a spline, which is formed from two meshing gears each with the same number of teeth, is known to correspond to the radial distance between the tip diameter of one of the gears and the root diameter of the other meshing gear.

[0010] The module of the spline represents a characteristic value of the spline, which corresponds to the quotient of a reference diameter of the spline and the number of teeth, whereby the reference diameter is approximately in the middle of the spline.

[0011] Due to the significantly increased backlash of the spline of the device according to the invention compared to known splines, which are designed and constructed, for example, in accordance with DIN 5481, the spline has the necessary elasticity to cushion and reduce shock loads acting on the shaft and gear. Depending on the specific application, this occurs either in the area of ​​the teeth of the internal gearing of the gear, in the area of ​​the teeth of the external tooth profile of the shaft, or in the area of ​​the teeth of the internal gearing of the gear and in the area of ​​the teeth of the external tooth profile of the shaft. These teeth, due to their larger tooth heights and narrower tooth widths, each have greater elasticity or are softer than the teeth of known splines.

[0012] The increased elasticity of the spline makes it possible to cushion or reduce the magnitude of high shock loads on the shaft and gear during operation, for example, resulting from sudden deceleration of the rotating shaft and the gear rotating with it. This is because the elasticity permits a defined relative rotational movement between a force application point on the gear and a force application area on the shaft. Compared to existing devices, this defined relative rotational movement is achieved in a structurally simple, space-saving and cost-effective manner without increasing the axial distance between the force application area on the shaft and the force application area on the gear. Furthermore, the damping of load peaks is also achieved by means of the device according to the invention without having to reduce the strength of the shaft and gear.

[0013] This is particularly advantageous in electric vehicle drivetrains, where the high gear ratios cause high, alternating, and high-frequency torque surges during the engagement of a parking lock. The elastic connection of the gear, which can be designed as a parking lock gear, for example, with the shaft serving as the drive shaft, reduces the severity, number, and magnitude of torque peaks. This increases service life, and both the shaft and the gear can be designed with lower strength, which has a positive impact on manufacturing costs.

[0014] Depending on the particular application, the at least one tip clearance of the spline may be greater than 0.6 times and less than 4 times, less than 3.5 times, less than 3 times, less than 2.5 times, less than 2 times or less than 1.5 times the module of the spline.

[0015] Furthermore, it can also be provided that the at least one tip clearance of the spline is greater than 0.7 times and less than 4 times, less than 3.5 times, less than 3 times, less than 2.5 times, less than 2 times or less than 1.5 times the module of the spline.

[0016] It is also possible that at least one of the basic backlash of the spline is greater than 0.8 times and less than 4 times, less than 3.5 times, less than 3 times, less than 2.5 times, less than 2 times or less than 1.5 times the module of the spline.

[0017] In addition, the at least one tip clearance of the spline to represent the elasticity in the area of ​​the spline can also be greater than 0.9 times and less than 4 times, less than 3.5 times, less than 3 times, less than 2.5 times, less than 2 times or less than 1.5 times the module of the spline.

[0018] In addition, the at least one tip clearance of the spline may also be greater than 1.0 times and less than 4 times, less than 3.5 times, less than 3 times, less than 2.5 times, less than 2 times or less than 1.5 times the module of the spline.

[0019] In a further embodiment of the device according to the invention, the at least one tip clearance of the spline is greater than 1.1 times and less than 4 times, less than 3.5 times, less than 3 times, less than 2.5 times, less than 2 times or less than 1.5 times the module of the spline.

[0020] The spline has an elasticity by means of which loads acting on the shaft and the gear can be dampened if the opening angle of the internal toothing is less than 40°, less than 30° or less than 20°.

[0021] In a simple to manufacture and cost-effective development of the device according to the invention, the tooth flanks of the internal toothing and / or the tooth flanks of the external tooth profile have a straight course.

[0022] Tooth root bending stresses can be reduced in the area of ​​the internal toothing and / or in the area of ​​the external tooth profile and the stiffness of the teeth of the internal toothing and / or the external tooth profile can be adjusted as required if areas of the tooth flanks of the internal toothing and / or areas of the tooth flanks of the external tooth profile outside the toothing engagement of the spline have a parabolic, an elliptical or an involute course.

[0023] In an advantageous embodiment of the device according to the invention, the tooth flanks of the external tooth profile and the tooth flanks of the internal toothing each have an involute course.

[0024] Alternatively, the tooth flanks of the external tooth profile and the tooth flanks of the internal toothing can each have a straight flank profile.

[0025] Furthermore, it is also possible for the tooth flanks of the external tooth profile to be straight-flanked and for the tooth flanks of the internal toothing to be involute.

[0026] In addition, it is possible for the profiles of areas of the tooth flanks of the internal gearing and / or the profiles of areas of the tooth flanks of the external tooth profile outside the tooth engagement of the spline to correspond to free-form curves which are designed to limit tooth root bending stresses of the spline to permissible values ​​and to design the teeth of the internal gearing and / or the external tooth profile with a desired rigidity.

[0027] An axial length of the internal toothing of the gear and / or an axial length of the external tooth profile can be designed depending on the tip clearance of the spline in order to provide a desired elasticity of the spline while simultaneously providing a high load-bearing capacity.

[0028] The gear can interact with an outer diameter area of ​​the shaft via an inner diameter area located axially adjacent to the internal toothing. This provides a simple design in which, in addition to the meshing between the gear and the shaft, the gear is supported axially on the outer diameter area of ​​the shaft. This allows the gear to be centered on the shaft and forces acting on the gear to be supported in the shaft area.

[0029] It is also possible for the gear to rest against a shaft collar with an axial end face of the inner diameter area, facing away from the internal toothing, and to be supported axially against it. This allows axial forces acting in the area of ​​the gear to be supported in the area of ​​the shaft in a simple design.

[0030] A press fit can also be formed between the inner diameter area of ​​the gear and the outer diameter area of ​​the shaft to dampen occurring load peaks.

[0031] A spring element can be arranged in the axial direction of the shaft between the axial end face of the inner diameter area of ​​the gear and the shaft collar. The spring element can be supported axially on the shaft and the gear in order to adapt the friction-induced damping effect between the end face of the inner diameter area and the shaft collar to suit the application and to limit any peak loads that occur as desired.

[0032] A surface roughness of the axial end face of the inner diameter area and / or a surface roughness of the axial end face of the shaft collar facing the axial end face of the inner diameter area can be designed to dampen relative rotational movement of the gear relative to the shaft by means of friction. This frictional damping of load peaks, in turn, makes it possible to easily limit load peaks occurring during operation to the required extent, in addition to the elastic design of the spline.

[0033] In a further development of the device according to the invention which can be installed with little effort and is structurally simple, the gear is supported on the shaft on the side facing away from the shaft shoulder by means of three snap rings in the axial direction. It can be provided that a first snap ring engages in a radial outer ring groove of the shaft and is encompassed on the circumferential side by a second snap ring. The second snap ring can bear with its outer diameter against an inner diameter of the gear and with its side surface facing the spline against an axial end face of the gear. It can also be provided that the second snap ring is arranged between the axial end face of the gear and a third snap ring which engages in a radial inner ring groove of the gear.

[0034] This ensures secure axial positioning and support of the gear on the shaft, even at high speeds of the shaft and gear.

[0035] The invention is not limited to the specified combination of features of the independent claims or the dependent claims. Furthermore, possibilities arise for combining individual features, even if they emerge from the claims, the following description of embodiments, or directly from the drawings. The reference of the claims to the drawings by the use of reference symbols is not intended to limit the scope of protection of the claims.

[0036] Preferred developments emerge from the dependent claims and the following description. Exemplary embodiments of the invention are explained in more detail with reference to the drawings, without being limited thereto.

[0037] It shows: Fig. 1 a three-dimensional partial representation of a drive train designed as an electric drive axle of a vehicle; Fig. 2 a three-dimensional longitudinal sectional view of a drive shaft and a gear wheel arranged thereon of the drive train according to Fig. 1, wherein the gear and the shaft are connected to each other in a rotationally fixed manner via a spline; Fig. 3 an exploded view of the shaft and the gear in a longitudinal section including several snap rings for axially fixing the gear on the shaft; Fig. 4 the shaft and the gear as well as the snap rings in assembled state in a three-dimensional longitudinal sectional view; Fig. 5 a longitudinal sectional view of a portion of the drive shaft and the gear Fig. 6 is a side view of a portion of a first embodiment of the spline between the shaft and the gear; Fig. 7 a Fig. 6 corresponding representation of a second embodiment of the spline; Fig. 8 a Fig. 6 corresponding representation of a third embodiment of the spline; and Fig. 9 a Fig. 6 corresponding representation of a fourth embodiment of the spline.

[0038] Fig. Figure 1 shows a three-dimensional partial representation of a drive train 1, which is designed as an electric drive axle of a vehicle. As is known, areas of electric vehicle axles are exposed to high torques, which require a corresponding design of the components. In principle, the drive train 1 can also be designed as an electric drive, via which the drive of an electric actuator is transmitted, whereby the torques acting in each case are significantly lower than with electric vehicle axles.

[0039] In this case, the drive train 1 comprises an electric machine 2 that can be operated as a motor. Depending on the particular application, it is also possible for the electric machine 2 to be operated both as a motor and as a generator in order to also be able to recuperate electrical energy during suitable operating states of the drive train 1.

[0040] An output shaft of the electric machine 2 is in this case connected in a rotationally fixed manner to a shaft 3, on which a gear 4 is arranged in a rotationally fixed manner via a device 100. On the circumference, the gear 4 is designed with a tooth profile 5, into which a pawl of a parking lock arrangement (not shown in detail here) engages in a conventional manner in order to be able to hold the shaft 3 in a rotationally fixed manner as needed.

[0041] The shaft 3 is designed with a toothed area 6, with which the shaft 3 engages with another gear 7 of a spur gear 8. Via the spur gear 8, the shaft 3 and thus the electric machine 2 are connected via one or more additional gear stages, depending on the application, to output shafts, which transmit a drive torque of the electric machine 2 toward the drive wheels of a vehicle or, during coasting of a vehicle, each direct a torque toward the electric machine 2.

[0042] Fig. 2 shows a three-dimensional longitudinal sectional view of the shaft 3 and the gear 4 arranged thereon. The gear 3 is arranged on the shaft 3 in a rotationally fixed manner via a shaft-hub connection or a spline 9 of the device 100. The spline 9 comprises an internal toothing 10 of the gear 4 and an external tooth profile 11 of the shaft 3 that meshes therewith. Furthermore, the gear 4 is formed in the axial direction X, next to the internal toothing 10, with an inner diameter region 12 via which the gear 4 interacts with an outer diameter region 13 of the shaft 3. The gear 4 is supported on the outer diameter region 13 of the shaft 3 and is centered accordingly. Furthermore, the gear wheel 4 rests with an axial end face 14 of the inner diameter region 12, which faces away from the internal toothing 10, on an end face of a shaft collar 15 of the shaft 3 and is supported on this in the axial direction X.

[0043] On the opposite side of the gear wheel 4, ie on the side facing away from the shaft collar 15, the gear wheel 4 is in the axial direction X over three Fig. 3, Fig. 4 and Fig. 5 are supported on the shaft 3. The first snap ring 16 engages in a radial outer ring groove 19 of the shaft 3 and is encompassed circumferentially by the second snap ring 17. This ensures that the first snap ring 16 is not expanded by the centrifugal forces acting on the first snap ring 16 during operation of the drive train 1 and the rotating shaft 3, and exits from the radial outer ring groove 19. In order to fix the gear 4 in the axial direction X on the shaft 3 by means of the first snap ring 16, the first snap ring 16 engages over the internal toothing 10 of the gear 4 in the radial direction Y due to its radial height H16.

[0044] The second snap ring 17 rests with its outer diameter against an inner diameter of the gear 3 and with its side surface 20 facing the spline 9 against an axial end face 21 of the gear 4. Additionally, the second snap ring 17 is arranged between the axial end face 21 of the gear 4 and the third snap ring 18, which engages in a radial inner ring groove 22 of the gear 3 and is held there in the axial direction X.

[0045] In Fig. 6 to Fig. 9 shows side views of areas of various embodiments of the splines 9A to 9D, each of which is designed with a defined elasticity in order to be able to limit the loads acting on the shaft 3 and the gear 4 during operation to permissible values. Load peaks acting on the shaft 3 occur, for example, when the parking lock pawl spontaneously engages the tooth profile 5 of the gear 4. In order to be able to limit load peaks in the area of ​​the splines 9A, 9B, 9C, 9D, the tip clearances c9A, c9B, c9C and c9D1, c9D2 of the splines 9A to 9D are, depending on the application, greater than 0.5 times the moduli of the splines 9A to 9D and less than 10 times the moduli of the splines 9A to 9D.The modules of the splines 9A to 9D are each equal to the quotients of the reference diameters d9A, d9B, d9C, d9D of the splines 9A, 9B, 9C, 9D and the number of teeth of the splines 9A, 9B, 9C, 9D.

[0046] In the Fig. In the embodiment of the spline 9A shown in Figure 6, the tip clearance c9A of the spline 9A between the tip diameter dK11 of the external tooth profile 11 and the root diameter dF10 of the internal toothing 10 is equal to 3 times the module of the spline 9A, which is many times larger than the tip clearance between the tip diameter dk10 of the internal toothing 10 and the root diameter dF11 of the external tooth profile 11.

[0047] Furthermore, the opening angle y10 of the internal toothing 10 is 20°, which allows the teeth 23, 24 of the spline 9A to be designed with larger flank curvatures compared to conventionally designed splines. In addition, the teeth 23 of the internal toothing 10 have straight tooth flanks and a defined root radius RF10. In contrast, the tooth flanks of the teeth 24 of the external tooth profile 11 of the spline 9A have an involute profile.

[0048] A tooth thickness ratio between the teeth 23 of the internal toothing 10 and the teeth 24 of the external tooth profile 11 is not balanced, since the teeth 24 of the external tooth profile 11 are significantly thicker than the teeth 23 of the internal toothing 10. The stiffness or flexibility of the splines 9A to 9D can be additionally defined via the tooth thickness ratio.

[0049] In contrast to spline 9A, the teeth 23 of spline 9B have non-straight tooth flanks. This offers the possibility of specifically influencing the tooth stiffness of teeth 23 and, to increase load-bearing capacity, optimizing tooth root bending stresses via a modified root contour between the non-straight tooth flanks, which have a free-form contour, instead of the defined root radius RF10.

[0050] For spline 9C according to Fig. 7, the tip clearance c9C between the tip diameter dK10 of the internal toothing 10 and the root diameter dF11 of the external tooth profile is equal to 1.8 times the module of the spline 9C and significantly larger than the tip clearance between the tip diameter dK11 of the external tooth profile 11 and the root diameter dF10 of the internal toothing 10. Tooth flanks of the teeth 23 are straight, while the tooth flanks of the teeth 24 are involute-shaped.

[0051] Another possible embodiment of the spline 9D is shown Fig. 8, in which the tip clearance c9D1 between the tip diameter dK10 of the internal toothing 10 and the root diameter dF11 of the external tooth profile 11 is equal to 1.5 times the module of the spline 9C and approximately corresponds to the tip clearance c9D2 between the tip diameter dK11 of the external tooth profile 11 and the root diameter dF10 of the internal toothing 10.

[0052] In addition, the axial length L10 of the internal toothing 10 of the gear 4 and the axial length L11 of the external tooth profile 11 can be designed accordingly in order to limit the load peaks in the area of ​​the shaft 3 and in the area of ​​the gear 4 during operation of the drive train 1.

[0053] In particular, the elasticity of the internal toothing 10 offers the possibility of limiting or dampening load shocks during engagement of the parking lock pawl into the tooth profile of the gear 4 in a structurally simple and cost-effective manner. During such an operating condition of the drive train 1, the teeth 23 of the internal toothing 10 are elastically and reversibly deformed due to their defined elasticity.

[0054] The elasticity of the internal toothing 10, and preferably also the elasticity of the external toothing 11, can be adjusted depending on the application by varying the radial height H10 of the internal toothing 10 of the gear 4, the radial height H11 of the external tooth profile 11, the depth of engagement of the teeth 23 of the internal toothing 10 into the external tooth profile 11 and the depth of engagement of the teeth 24 of the external tooth profile 11 into the internal toothing 10 and thus ultimately the tip clearances.

[0055] In addition, the elasticity of the spline 9 can be adjusted to permissible values ​​depending on the application in order to dampen load peaks by appropriately designing the number of teeth of the internal toothing 10 of the gear 4 and the number of teeth of the external tooth profile 11.

[0056] A press fit is provided between the inner diameter area 12 of the gear 4 and the outer diameter area 13 of the shaft 3. This, on the one hand, achieves the desired good positioning of the gear 4 on the shaft 3. On the other hand, the press fit additionally dampens a relative rotational movement between the shaft 3 and the gear 4 within the maximum possible rotational angle offset depending on the design. This allows the internal toothing 10 and the external tooth profile 11 to be designed with a lower strength, if necessary.

[0057] In addition to the interference fit or alternatively thereto, it is also possible that the surface roughness of the axial end face 14 of the inner diameter region 12 and / or the surface roughness of the axial end face of the shaft collar 15 facing the axial end face 14 of the inner diameter region 12 is or are designed to dampen a relative rotational movement between the gear 4 and the shaft 3 by means of friction.

[0058] In order to be able to vary the damping friction force between the shaft collar 15 and the end face 14 of the gear 4 depending on the application, it is possible to arrange a spring element 25, for example a disc spring, a wave spring, a spring plate, or the like, between the end face 14 and the axial end surface 15A of the shaft collar 15. Using such a spring element 25, an axial contact force between the shaft collar 15 and the axial end face 14 of the gear 4 can be adjusted accordingly and can be increased with little effort compared to a springless embodiment of the device 100. Reference symbol 1 drivetrain 2 electric machine 3 Wave 4 gear 5 Tooth profile of gear 4 6 Gearing area of ​​the shaft 3 7 additional gear 8 spur gears 9 Spline 9A to 9D spline 10 Internal teeth of gear 4 11 External tooth profile of shaft 3 12 Inner diameter range of gear 4 13 Outer diameter range of the shaft 3 14 axial face of gear 4 15 Wave collar 15A axial end face of the shaft collar 15 16 first snap ring 17 second snap ring 18 third snap ring 19 Outer ring groove of shaft 3 20 Side surface of the second snap ring 17 21 axial face of gear 4 22 inner ring groove 23 teeth of the internal gearing 24 teeth of the external tooth profile 25 spring element 100 device c9A Head clearance of the spline 9A c9B Head clearance of the spline 9B c9C Head clearance of the spline 9C c9D1, c9D2 backlash of spline 9D d9A Reference diameter of the spline 9A d9B Reference diameter of the spline 9B d9C Reference diameter of the spline 9A d9D Reference diameter of the spline 9D dK10 Tip diameter of the internal gear 10 dF10 Root diameter of the internal gear 10 dK11 Tip diameter of the external tooth profile 11 dF11 Root diameter of the external tooth profile 11 L10 axial length of the internal gearing L11 axial length of the external tooth profile H10 Height of internal toothing 10 H11 Height of the external tooth profile H16 radial height of the first snap ring 16 RF10 Root radius of the internal gear 10 X axial direction Y radial direction γ10 Opening angle of the internal gear 10 QUOTES CONTAINED IN THE DESCRIPTION

[0000] This list of documents submitted by the applicant was generated automatically and is included solely for the convenience of the reader. This list is not part of the German patent or utility model application. The DPMA assumes no liability for any errors or omissions. Cited patent literature

[0000] DE 10 2020 207 340 A1

[0003]

Claims

[1] Device (100) for the rotationally fixed connection of a shaft (3) to a gear (4) arranged thereon via a spline (9; 9A; 9B; 9C; 9D) comprising an internal toothing (10) of the gear (4) and an external tooth profile (11) of the shaft (3) engaging therewith, characterized by in order to limit load peaks to permissible values, at least one basic head clearance (c9A; c9B; c9C; c9D1, c9D2) of the spline (9; 9A; 9B; 9C; 9D) is greater than 0.5 times the module of the spline (9; 9A; 9B; 9C; 9D) and less than 10 times the module of the spline (9; 9A; 9B; 9C; 9D). [2] Device according to claim 1, characterized by that the at least one head clearance (c9A; c9B; c9C; c9D1, c9D2) of the spline (9; 9A; 9B; 9C; 9D) is greater than 0.6 times, greater than 0.7 times, greater than 0.8 times, greater than 0.9 times, greater than 1.0 times or greater than 1.1 times the module of the spline (9; 9A; 9B; 9C; 9D). [3] Device according to claim 1 or 2, characterized by that the at least one head base clearance (c9A; c9B; c9C; c9D1, c9D2) of the spline (9; 9A; 9B; 9C; 9D) is less than 4 times, less than 3.5 times, less than 3 times, less than 2.5 times, less than 2 times or less than 1.5 times the module of the spline (9; 9A; 9B; 9C; 9D). [4] Device according to one of claims 1 to 3, characterized by that the opening angle (y10) of the internal toothing (10) is less than 40°, less than 30° or less than 20°. [5] Device according to one of claims 1 to 4, characterized by that tooth flanks of the internal toothing (10) and / or tooth flanks of the external tooth profile (11) have a straight course. [6] Device according to one of claims 1 to 4, characterized bythat areas of the tooth flanks of the internal toothing (10) and / or areas of the tooth flanks of the external tooth profile (11) outside the toothing engagement of the spline toothing (9) have a parabolic, an elliptical or an involute-shaped course. [7] Device according to one of claims 1 to 4, characterized by that the profiles of regions of the tooth flanks of the internal toothing (10) and / or the profiles of regions of the tooth flanks of the external tooth profile (11) correspond to free-form curves which are designed to limit tooth root bending operating stresses of the spline toothing (9; 9A; 9B; 9C; 9D) to permissible values. [8] Device according to one of claims 1 to 7, characterized bythat the gear (4) with an inner diameter region (12) arranged in the axial direction (X) next to the internal toothing (10) cooperates with an outer diameter region (13) of the shaft (3) and the gear (4) is supported with the inner diameter region (12) for centering on the outer diameter region (13) on the shaft (3). [9] Device according to claim 8, characterized by that the gear (4) with an axial end face (14) of the inner diameter region (12), which faces away from the internal toothing (10), rests against a shaft collar (15) of the shaft (3) and is supported on this in the axial direction (X). [10] Device according to claim 8 or 9, characterized by that a press fit is formed between the inner diameter region (12) of the gear (4) and the outer diameter region (13) of the shaft (3). [11] Device according to one of claims 8 to 10, characterized bythat in the axial direction (X) of the shaft (3) between the axial end face (14) of the inner diameter region (12) of the gear (4) and the shaft collar (15) a spring element (25) is arranged, which is supported in the axial direction (X) on the shaft (3) and on the gear (4). [12] Device according to one of claims 8 to 11, characterized by that the surface roughness of the axial end face (14) of the inner diameter region (12) and / or the surface roughness of the axial end face of the shaft collar (15) facing the axial end face (14) of the inner diameter region (12) is or are designed to dampen a relative rotational movement of the gear wheel (4) relative to the shaft (3) by means of friction. [13] Device according to one of claims 9 to 12, characterized byin that the gear (4) is supported on the shaft (3) on the side facing away from the shaft collar (15) via three snap rings (16 to 18) in the axial direction (X), wherein a first snap ring (16) engages in a radial outer ring groove (19) of the shaft (3) and is encompassed on the circumference by a second snap ring (17), which bears with its outer diameter against an inner diameter of the gear (4) and with its side surface (20) facing the spline (9) against an axial end face (21) of the gear (4), and wherein the second snap ring (17) is arranged between the axial end face (21) of the gear (4) and a third snap ring (18) which engages in a radial inner ring groove (22) of the gear (4).

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