Hub body for compound wheel, in particular compound gear, compound wheel, in particular compound gear, and steering unit for motor vehicle

Abstract

The invention relates to a hub body (16) for a compound wheel (10), in particular a compound gear (12), having an axis of rotation (14), a first hub end face (20), a second hub end face (22), an outer jacket surface (24) arranged along the axis of rotation (14) between the first hub end face (20) and the second hub end face (22), wherein the outer jacket surface (24) has a drive tooth portion (28) comprising at least one drive tooth (30) and a convex outer jacket portion (64). The invention also relates to a compound wheel (10), in particular a compound gear (12), having such a hub body (16), and to a steering unit for a motor vehicle having such a compound wheel.

Description

Field of the Invention

[0001] The present invention relates to a hub body for a compound wheel, in particular a compound gear, and a steering unit for a motor vehicle. Background Art

[0002] Compound wheels are mainly used as compound gears, for example in the steering unit of a motor vehicle, and generally have a hub body and an annular body radially arranged outside the hub body. In a compound gear, the annular body includes external teeth that can mesh with another gear. Therefore, in this particular example of a compound wheel, the annular body is generally referred to as a gear ring.

[0003] The hub body and the annular body are generally made of different materials. For example, the hub body is generally made of metal, and the annular body is made of plastic. For example, the manufacturing process known from EP 1 780 445 A1 provides that a metal hub body is overmolded with an annular body in a plastic injection molding process.

[0004] In order to obtain a permanent connection between the hub body and the annular body, the hub body and the annular body are generally connected to each other in a form-fitting manner. It is known to apply a driving tooth portion on the hub body in order to transmit torque between the hub body and the annular body. In order to transmit axial forces, shoulders and / or grooves are arranged on the hub body, and the annular body engages into the shoulders and / or grooves.

[0005] The shoulders and / or grooves are generally limited by relatively sharp edges, especially in the axial direction. By applying the driving tooth portion, additional sharp edges can be generated on the hub body. The driving tooth portion is generally produced by hobbing, and in particular sharp edges may be formed in the tool exit area or in the area where the driving tooth portion passes through the shoulder or the groove.

[0006] During the cooling process of the plastic injection molded annular body, due to the notch stress concentration effect, the sharp edges often cause shrinkage stress cracks, resulting in premature failure of the component. During operation, the radial and axial forces at the sharp edges also cause local stress increases, thereby exacerbating the formation and propagation of cracks.

[0007] The grooves specifically applied to the hub body may also not shrink by reducing the specific volume of the plastic during the cooling process. Therefore, when using the corresponding compound wheel, unwanted noises and / or play often occur repeatedly between the hub body and the annular body during load changes, especially during load changes in the axial direction. This not only shortens the service life of the component. It also affects the quality and comfort of the steering unit using such a compound wheel. Summary of the Invention

[0008] The object of the present invention is to provide a hub body for a composite wheel, which can produce a composite wheel that is durable, reliable and meets comfort requirements, and is easy to manufacture. The object of the present invention is also to provide a durable, reliable and easy-to-manufacture composite wheel that meets comfort requirements. In addition, the object of the present invention is to provide a high-quality, comfortable but at the same time inexpensive steering unit.

[0009] According to the present invention, these objects are achieved by a hub body according to one aspect of the present invention, a composite wheel according to another aspect of the present invention, and a steering unit according to yet another aspect of the present invention. Advantageous embodiments and further aspects of the present invention are other aspects of the present invention.

[0010] A hub body for a composite wheel, in particular a composite gear, according to the present invention has a rotational axis, a first hub end side, a second hub end side, and an outer jacket surface wherein the outer jacket surface is arranged between the first hub end side and the second hub end side along the rotational axis. The outer jacket surface has a drive tooth portion including at least one drive tooth. Preferably, the drive tooth portion has a plurality of drive teeth corresponding to the at least one drive tooth and uniformly arranged in the circumferential direction of the outer jacket surface around the rotational axis. The outer jacket surface may have a protruding outer jacket portion. Thus, the outer jacket surface is at least partially, preferably spherical. Thus, the ring body of the composite wheel injection-molded on the hub can shrink onto the hub body, thereby improving the strength and stiffness of the connection between the hub body and the ring body. In addition, the axial force can be particularly advantageously transmitted through the protruding outer jacket portion. Preferably, the protruding outer jacket portion is arranged circumferentially around the rotational axis. Thus, the protruding outer jacket portion is preferably visible in a sectional view of the hub body along the rotational axis.

[0011] In a preferred embodiment of the present invention, the root circle diameter of the drive tooth portion has a root circle diameter curve along the at least one drive tooth. The drive tooth portion can be designed as a straight tooth portion. In this case, the at least one drive tooth is aligned along the rotational axis. The root circle diameter curve can have a maximum portion.

[0012] Preferably, the maximum portion of the root circle diameter curve is arranged in the protruding outer jacket portion. Within the protruding outer jacket portion, the root circle diameter curve can have a convex root circle portion having a convex radius. The convex radius can be constant or variable. Preferably, the maximum portion of the root circle diameter curve is arranged in the convex root circle portion. The drive tooth portion can have a hemispherical profile on both sides of the protruding outer jacket portion, respectively.

[0013] Preferably, the first hub end side has a first hub end face, and the second hub end side has a second hub end face. The second hub end side is preferably arranged axially opposite to the first hub end face. The maximum portion can be arranged to be spaced apart from the first hub end face and / or the second hub end face. The arrangement of the maximum portion being at least spaced apart from the hub end face can avoid the adverse superposition of stresses acting on the ring body. The ring body can have a ring face corresponding to the hub end face. Although the operating stresses usually generated by applying an external force to the composite wheel during operation can generally be observed in the region of the first ring face and the first hub end face, the shrinkage stresses occurring in the ring body occur in the protruding outer jacket portion, particularly in the region near the maximum portion. In addition, by a forming manufacturing process such as sintering or a forming manufacturing process such as extrusion, a drive gear having the maximum portion in the pitch circle diameter curve can be easily produced.

[0014] Unless otherwise specified, the terms "radial" and "axial" herein and hereinafter are with respect to the axis of rotation. A surface, such as the surface of the first hub end face, is referred to as an "end face" herein and hereinafter, and preferably defines the corresponding body, i.e., the hub body or the ring body, axially. The surface referred to as an "end face", particularly the face of the hub body, can form a conical shape or have other shapes around the axis of rotation. The face referred to as an "end face" is preferably arranged orthogonally to the axis of rotation. The face of the first hub end side arranged orthogonally to the axis of rotation is preferably assigned to the first hub end face. The outer jacket surface is preferably arranged as an annulus around the axis of rotation.

[0015] In addition, the maximum portion can be arranged at the center or offset from the center between the first hub end face and the second hub end face. Therefore, the arrangement of the maximum portion can be matched with the manufacturing process, particularly the manufacturing process of the ring body, so that, for example, the formation of shrinkage cavities in the ring body can be avoided. The first hub end face and / or the second hub end face are preferably arranged orthogonally to the axis of rotation. The face of the corresponding hub end side arranged orthogonally to the axis of rotation is preferably assigned to the corresponding hub end face. For example, a section of the hub body can have the above-mentioned face. Preferably, the outer jacket surface is different from the first hub end face and / or the second hub end face. The outer jacket surface can axially adjoin the first hub end face and / or the second hub end face.

[0016] The hub body can be designed such that the first root circle end diameter (Fuβkreisstirndurchmesser) is arranged in the first hub end face and / or the second root circle end diameter is arranged in the second hub end face. The first root circle end diameter can be equal to or different from the second root circle end diameter. Preferably, the first root circle end diameter and / or the second root circle end diameter respectively form the end points of the root circle diameter curve. This enables the root circle diameter curve to be adapted to the corresponding application, in particular the expected axial force. In addition, the hub body can thus be advantageously designed for the application of the ring body by injection molding. In particular, the uneven shrinkage behavior of the plastic on both sides of the maximum can be compensated for.

[0017] In a preferred embodiment of the invention, the root circle diameter curve from the first hub end face to the second hub end face is continuously (durchgehend stetig) and / or differentiable. Therefore, the root circle diameter curve is preferably not interrupted by a groove extending in the circumferential direction. In addition, sharp edges along the root circle diameter curve and the associated notch stress concentration effect can be avoided. In an embodiment of the invention, the outlet of the drive tooth portion is arranged only in the first hub end face and / or the second hub end face. Therefore, the outer jacket surface can be designed without the outlet of the drive tooth portion. The at least one drive tooth can particularly extend continuously from the first hub end face to the second hub end face.

[0018] In an embodiment of the invention, the protruding outer jacket portion extends from the first hub end face to the second hub end face. This enables the drive tooth portion to be formed particularly uniformly. In addition, such a drive tooth portion has lower requirements for the tools required for production.

[0019] In a further aspect of the invention, the root circle diameter curve has a first recess, and the first recess has a preferably constant first cavity radius. A drive tooth portion having such a root circle diameter curve can be simply produced by hobbing. With such a root circle diameter curve, the drive tooth portion can at least partially have a hemispherical profile. In an alternative embodiment, the first cavity radius can be designed to be variable.

[0020] Preferably, the root circle diameter curve has a second recess, and the second recess has a preferably constant second cavity radius. The first cavity radius can be equal to or different from the second cavity radius. Therefore, another possibility is to adapt the root circle diameter curve to the corresponding application, in particular the expected axial force, and / or to advantageously design the hub body for the application of the ring body by injection molding. The maximum of the root circle diameter curve can be arranged between the first recess and the second recess. In particular, the uneven shrinkage behavior of the plastic on both sides of the maximum can be compensated for thereby.

[0021] In a further embodiment of the present invention, the drive tooth portion is designed as a helical tooth. Therefore, a part of the axial force transmitted between the ring body and the hub body can additionally be transmitted through the drive tooth surfaces of the at least one drive tooth. This can further extend the service life of the composite wheel. If the composite wheel is designed as a helical composite gear, the drive tooth portion and the composite wheel tooth portion of the composite wheel are inclined relative to the axis of rotation in the same direction. Particularly preferably, the drive inclination angle of the drive tooth portion is less than or equal to the composite wheel inclination angle of the composite wheel tooth portion.

[0022] The tooth height of the at least one drive tooth can be at least partially constant along the drive tooth surface of the at least one drive tooth. Therefore, during the production of the hub body, sharp edges on the drive tooth portion can be avoided.

[0023] The composite wheel according to the present invention, in particular a composite gear, comprises the above-mentioned hub body and a ring body, which is arranged radially outside the hub body.

[0024] When the terms "concave" and "convex" are related to the pitch circle diameter curve here and hereinafter, they preferably refer to the ring body. Therefore, the convex portion preferably describes an arc rising towards the ring body. The concave portion preferably represents a notch opening towards the ring body.

[0025] The ring body and the drive tooth portion are arranged to engage with each other. The ring body can have an inner ring diameter, which can correspond to the outer hub diameter of the hub body. In particular, through the drive tooth portion, the inner ring diameter and the outer hub diameter can be designed to be variable along the circumference of the composite wheel. Therefore, preferably, the outer hub diameter is defined by the tip diameter of the drive tooth portion at the tip of the at least one drive tooth and by the root circle diameter of the drive tooth portion at the root of the at least one drive tooth. The inner ring diameter and / or the outer hub diameter can be designed to be variable along the axis of rotation.

[0026] Preferably, the hub body is made of metal, particularly preferably made of steel. The ring body is preferably made of plastic, particularly preferably made of POM. In particular, the ring body can be manufactured by a plastic injection molding process, preferably by directly injection molding the ring body onto the hub body. Preferably, the ring body directly abuts against the hub body and is flush with the hub body.

[0027] The annular body has a first axial annular body end and a second axial annular body end. The first axial annular body end and / or the second axial annular body end can be arranged only on the outer jacket surface of the hub body, preferably along the entire circumference of the composite wheel. The first axial annular body end and / or the second axial annular body end on one hand and the hub body on the other hand are preferably effectively connected to each other only in the radial direction. Thus, in particular, a projection of the annular body that is radially directed towards the axis of rotation for transmitting an axial force between the hub body and the annular body can be omitted, and the associated notch stress concentration effect can be avoided. At the first axial annular body end, the inner diameter of the ring can have a first annular inner end diameter. Preferably, the first axial annular body end having the first annular inner end diameter is arranged on the outer jacket surface. At the second axial annular body end, the inner diameter of the ring can have a second annular inner end diameter. Preferably, the second axial annular body end having the second annular inner end diameter is arranged on the outer jacket surface.

[0028] In particular, the annular body can abut against only the outer jacket surface of the hub body in the region of the first hub end side and / or the second hub end side. The annular body can abut against the outer jacket surface of the hub body such that the annular body is arranged to radially adjoin the first hub end face and / or the second hub end face, preferably only adjoining these hub end faces.

[0029] In a preferred embodiment of the invention, the drive tooth part is arranged to penetrate the first annular end face. The axial end of the drive tooth part can be arranged in the first hub end face. Thus, the sharp edge that usually appears at the outlet of the drive tooth part is preferably not surrounded by the annular body. This can prevent notch stress in the annular body from occurring at the outlet of the drive tooth part. The maximum of the pitch circle diameter curve can allow the transmission of an axial force between the hub body and the annular body. The first annular end face is preferably arranged orthogonally to the axis of rotation. The first annular inner end diameter can be arranged in the same plane as the first annular end face. Preferably, the drive tooth part is arranged to penetrate the first annular end face such that the first annular end face directly adjoins the drive tooth part radially. The first annular end face and the first hub end face can be arranged in the same plane. Thus, the first annular end face and the first hub end face can be arranged adjacent to each other radially. Alternatively, the first annular end face and the first hub end face can be arranged in different planes.

[0030] The annular body preferably has, at the second axial end of the annular body, a second annular end face which is arranged axially opposite the first annular end face, and the drive tooth part is arranged to penetrate into the second annular end face. Thus, the negative influence of the sharp edge of the hub body described above on the annular body in the region of the second annular end face can be avoided. Preferably, the drive tooth part is arranged to penetrate into the second annular end face such that the second annular end face is directly adjacent to the drive tooth part in the radial direction. The second annular end face and the second hub end face may be arranged in the same plane. Thus, the second annular end face and the second hub end face may be arranged to be adjacent to each other in the radial direction. Alternatively, the second annular end face and the second hub end face may be arranged in different planes. Preferably, the second annular end face is arranged to be orthogonal to the axis of rotation.

[0031] The steering unit for a motor vehicle according to the invention comprises the composite wheel described above. BRIEF DESCRIPTION OF THE DRAWINGS

[0032] Embodiments of the invention are explained with reference to the following drawings. Shown in the drawings are:

[0033] Figure 1a A schematic perspective sectional view showing a first embodiment of the composite wheel,

[0034] Figure 1b Showing Figure 1a A schematic two-dimensional sectional view of the embodiment shown,

[0035] Figure 2a A schematic perspective sectional view showing a second embodiment of the composite wheel,

[0036] Figure 2b Showing Figure 2a A schematic two-dimensional sectional view of the embodiment shown,

[0037] Figure 3a A schematic perspective sectional view showing a third embodiment of the composite wheel,

[0038] Figure 3b Showing Figure 3a A schematic two-dimensional sectional view of the embodiment shown,

[0039] Figure 4a A schematic perspective sectional view showing a fourth embodiment of the composite wheel,

[0040] Figure 4b Showing Figure 4a A schematic two-dimensional sectional view of the embodiment shown,

[0041] Figure 5a A schematic perspective sectional view showing a fifth embodiment of the composite wheel,

[0042] Figure 5b ShowingFigure 5a Schematic two - dimensional sectional view of the illustrated embodiment. Detailed implementation

[0043] Figures 1a to 5b Shows different views of different embodiments. For clarity, not all reference numerals are used in each figure. The same reference numerals are used for identical and functionally identical components. The figures indexed as b, i.e. Figure 1b , Figure 2b etc. (hereinafter simply referred to as "Figure b") respectively show two - dimensional sectional views of the embodiments shown in the figures indexed as a, i.e. Figure 1a , Figure 2a etc. (hereinafter simply referred to as "Figure a").

[0044] Figure a shows a schematic perspective sectional view of a composite wheel 10 designed as a composite gear 12. The composite wheel 10 includes a rotational axis 14, a hub body 16, and a ring body 18 arranged radially outside the hub body 16. The hub body 16 has a first hub end side 20, a second hub end side 22, and an outer jacket surface 24, where the first hub end side 20 has a first hub end face 26. The outer jacket surface 24 is arranged between the first hub end side 20 and the second hub end side 22 along the rotational axis 14. The outer jacket surface 24 also has a drive tooth portion 28 including a plurality of drive teeth 30, and the drive teeth are evenly arranged in the circumferential direction 32 of the outer jacket surface 24 around the rotational axis 14. Figure 1a It is clearly shown that the first hub end face 26 is arranged orthogonally to the rotational axis 14, and the outer jacket surface 24 is arranged annularly around the rotational axis 14. The ring body 18 and the drive tooth portion 28 are arranged to engage with each other.

[0045] The ring body 18 has a ring inner diameter 19, which can correspond to the hub outer diameter 17 of the hub body 16. In particular, through the drive tooth portion 28, the ring inner diameter 19 and the hub outer diameter 17 are designed to be variable along the circumference of the composite wheel 10. Thus, the hub outer diameter 17 at the tooth tip 31 of one of the drive teeth 30 can be defined by the pitch circle diameter of the drive tooth portion 28, and the hub outer diameter 17 at the tooth root 33 of one of the drive teeth 30 can be defined by the root circle diameter 34 of the drive tooth portion 28. As shown in the embodiment of Figures 1a to 4b , the ring inner diameter 19 and / or the hub outer diameter 17 along the rotational axis 14 can be designed to be variable.

[0046] Preferably, the hub body 16 is made of metal, particularly preferably made of steel. The ring body 18 is preferably made of plastic, particularly preferably made of POM. In particular, the ring body 18 can be manufactured by a plastic injection molding process, preferably such that the ring body 18 is directly injection - molded onto the hub body 16. In this way, the arrangement shown in the figure can be achieved, where the ring body 18 directly abuts against the hub body 16 and is flush with the hub body 16.

[0047] As shown in Fig. a, the cross-section in Fig. b passes through the gap between two drive teeth 30 and extends along the drive teeth 30. In Figures 1a to 2b and Figures 4a to 5b of the embodiments, the drive tooth portion 28 is formed as straight teeth. Therefore, the drive teeth 30 shown in these figures and the cutting plane of the shown cross-section are respectively arranged along the rotation axis 14. The root circle diameter 34 of the drive teeth 30 has a root circle diameter curve 36 along the drive teeth 30, and this root circle diameter curve can be clearly identified based on the selected cutting plane along the drive teeth 30, especially in Fig. b. As shown in Fig. a, the root circle diameter curve 36 has a maximum portion 38 spaced apart from the first hub end face 26.

[0048] In all the shown embodiments, the annular body 18 has a first axial annular body end 18a and a second axial annular body end 18b. The first axial annular body end 18a is arranged only on the outer jacket surface 24 of the hub body 16 along the entire circumference of the composite wheel 10. In particular, in the first and third embodiments ( Figure 1a , Figure 1b , Figure 3a , Figure 3b ), the first axial annular body end 18a and the hub body 16 are only effectively connected to each other in the radial direction. At the first axial annular body end 18a, the inner ring diameter 19 has a first annular inner end diameter 19a. The first axial annular body end 18a and the first annular inner end diameter 19a are arranged on the outer jacket surface 24.

[0049] In Figures 1a to 5b of the embodiments, the annular body 18 abuts only against the outer jacket surface 24 of the hub body 16 in the region of the first hub end side 20. The annular body 18 can be arranged to be only adjacent to the first hub end face 26 in the radial direction.

[0050] For example, observing Figure 1b the lower half of the shown cross-sectional view, it can be well understood that the plastic injection molded annular body 18 shrinks to the maximum portion 38 when cooled. Higher shrinkage stresses also occur here. The operating stresses usually generated during operation due to the application of external forces to the composite wheel 10 can generally be observed at the first axial annular body end 18a in the region of the first annular end face 40 and the first hub end face 26, so that a relatively uniform stress distribution can be achieved through the shown arrangement.

[0051] In Figures 1a to 5bIn an embodiment, each drive tooth portion 28 is arranged to penetrate the first annular end face 40. The axial end portion of the drive tooth portion 28 is arranged in the first hub end face 26. The first annular end face 28 is arranged to be orthogonal to the rotational axis 14. The perspective view of FIG. a shows that the drive tooth portion 28 is arranged to penetrate the first annular end face 40 such that the first annular end face 40 is directly adjacent to the drive tooth portion 28 in the radial direction. The first annular end face 40 and the first hub end face 26 may be arranged in the same plane. In addition, in the corresponding embodiment, the first annular end face 40 and the first hub end face 26 are arranged to be adjacent to each other in the radial direction.

[0052] As shown in the two-dimensional cross-sectional view of FIG. b, the second hub end side 22 has a second hub end face 44, and the second hub end face is arranged to be opposite to the first hub end face 26 in the axial direction. The maximum portion 38 may be arranged at the center ( Figure 1a , Figure 1b , Figures 3a to 4b ) or eccentrically ( Figure 2a , Figure 2b ) between the first hub end face 26 and the second hub end face 44. In the fifth embodiment, there are two maximum portions 38. These two maximum portions 38 may have different sizes. These are also eccentrically arranged ( Figure 5a , Figure 5b ). In all the illustrated embodiments, the maximum portion 38 is arranged to be spaced apart from the second hub end face 44. Similar to the first hub end face 26, the second hub end face 44 is also arranged to be orthogonal to the rotational axis 14. In addition, FIG. b shows that the tooth height 45 of the drive tooth 30 along the drive tooth surface is at least partially constant.

[0053] In Figures 1a to 5b 's embodiment, the ring body 18 only abuts against the outer jacket surface 24 of the hub body 16 in the region of the second hub end side 22. The second axial ring body end 18b is particularly arranged only on the outer jacket surface 24 of the hub body 16 along the entire circumference of the composite wheel 10. The second axial ring body end 18b has a second annular inner end diameter 19b, and the second axial ring body end 18b and the second annular inner end diameter are arranged on the outer jacket surface 24. In particular, the ring body 18 can abut against the outer jacket surface of the hub body 16 such that the ring body is arranged to be only adjacent to the second hub end face 44 in the radial direction.

[0054] The ring body 18 has a second annular end face 48 arranged to be opposite to the first annular end face 40 in the axial direction at the second axial ring body end 18b, and the second annular end face is arranged to be orthogonal to the rotational axis 14. In Figures 1a to 5b 's embodiment, the drive tooth portion 28 is arranged to penetrate the second annular end face 48 such that the second ring end side 48 is directly adjacent to the drive tooth portion 28 in the radial direction. The second annular end face 48 and the second hub end face 44 may be arranged in the same plane and be adjacent to each other in the radial direction.

[0055] As shown in Fig. b, the compound wheel 10 can be designed such that a first root circle end diameter 50 is arranged in the first hub end face 26 and / or a second root circle end diameter 52 is arranged in the second hub end face 44. The first root circle end diameter 50 can be equal to ( Figure 1b , Figure 3b , Figure 4b , Figure 5b ) or not equal to ( Figure 2b ) the second root circle end diameter 52. As shown in Fig. b, the first root circle end diameter 50 and / or the second root circle end diameter 52 respectively form the endpoints of the root circle diameter curve 36. Therefore, the compound wheel 10 can be adjusted, for example, for the expected axial force and / or for the production boundary conditions.

[0056] In the Figures 1a to 4b embodiment, the root circle diameter curve 36 is also formed to be continuous and differentiable from the first hub end face 26 to the second hub end face 44. This is particularly shown in Figure 1b , Figure 2b , Figure 3b and Figure 4b .

[0057] In the Figures 1a to 3b embodiment, the root circle diameter curve 36 and the first recess 54 in the fifth embodiment have the form of a notch opening towards the ring body 18, which has a preferably constant first cavity radius 56.

[0058] In the Figures 1a to 3b and Figure 5a and Figure 5b embodiments, the root circle diameter curve 36 also has a second recess 58, which has a preferably constant second cavity radius 60. Although the first cavity radius 56 is equal to the second cavity radius 60 in the first, third and fifth embodiments, in the second embodiment, the first cavity radius 56 is not equal to the second inner cavity radius 60. As Figures 1a to 3b further shown, the maximum portion 38 of the root circle diameter curve 36 can be arranged between the first recess 54 and the second recess 58.

[0059] As Figures 1a to 5b shown, the outer jacket surface 24 can have a protruding outer jacket portion 64 in the form of an arc rising towards the ring body. The maximum portion of the root circle diameter curve 36 is arranged within the protruding outer jacket portion 64. In the Figures 1a to 4b embodiment, the root circle diameter curve 36 within the protruding outer jacket portion 64 has a protruding root circle portion 66, which has a convex radius 68. The maximum portion 38 of the root circle diameter curve 36 is arranged in the protruding root circle portion 66. At least in the fourth embodiment, the convex radius 68 is designed to be constant. In Figures 1a to 3b as well asFigure 5a and Figure 5b In the embodiments of Figure 5b , the first chamber radius 56 and the second chamber radius 60 are both constant on both sides of the protruding outer jacket portion 64, such that the drive tooth portion 28 partially has a hemispherical profile respectively.

[0060] In the fourth embodiment, the protruding outer jacket portion 64 extends from the first hub end face 26 to the second hub end face 44 ( Figure 4a and Figure 4b ).

[0061] As Figure 3a shown, the drive tooth portion 28 can also be designed as a helical tooth. Therefore, a part of the axial force transmitted between the ring body 18 and the hub body 16 can additionally be transmitted through the drive tooth surface of the drive tooth 30. Similar to all the embodiments shown, Figure 3a the composite wheel 10 shown can also be designed as a helical composite gear 12. In the case of the helical drive tooth portion 28 of the third embodiment, the drive tooth portion 28 of the composite wheel 10 and the composite wheel tooth portion 70 are respectively inclined in the same direction relative to the rotation axis 14. In the third embodiment, the drive inclination angle of the drive tooth portion 28 is smaller than the composite wheel inclination angle of the composite wheel tooth portion 70 ( Figure 3a ).

[0062] List of reference numerals

[0063] 10 Composite wheel

[0064] 12 Composite gear

[0065] 14 Rotation axis

[0066] 16 Hub body

[0067] 17 Hub outer diameter

[0068] 18 Ring body

[0069] 18a First axial ring body end

[0070] 18b Second axial ring body end

[0071] 19 Ring inner diameter

[0072] 19a First annular inner end diameter

[0073] 19b Second annular inner end diameter

[0074] 20 First hub end side

[0075] 22 Second hub end side

[0076] 24 Outer jacket surface

[0077] 26 First hub end face

[0078] 28 driving gear

[0079] 30 driving teeth

[0080] 31 tooth top

[0081] 32 Circumferential direction

[0082] 33 tooth root

[0083] 34 tooth root diameter

[0084] 36 tooth root diameter curve

[0085] 38 largest

[0086] 40 first annular end surface

[0087] 42Exit

[0088] 44 Second hub end face

[0089] 45 tooth height

[0090] 46 protrusions

[0091] 48 second annular end surface

[0092] 50 Diameter of the first tooth root circle

[0093] 52 Diameter of the second tooth root circle

[0094] 54 first recess

[0095] 56 First cavity radius

[0096] 58 Second recess

[0097] 60 Second cavity radius

[0098] 64 protruding outer jacket portion

[0099] 66 Protruding root circle part

[0100] 68 convex radius

[0101] 70 composite gear teeth.

Claims

1. A hub body (16) for a compound wheel (10), in particular a compound gear (12), having: · a rotational axis (14), · a first hub end face (20), · a second hub end face (22), · an outer jacket surface (24) arranged along the rotational axis (14) between the first hub end face (20) and the second hub end face (22), wherein the outer jacket surface (24) has a drive tooth portion (28) including at least one drive tooth (30), characterized in that the outer jacket surface (24) has a raised outer jacket portion (64).

2. The hub body according to claim 1, characterized in that the drive tooth portion (28) has a root circle diameter curve (36) along the root circle diameter (34) of at least one drive tooth (30), and the root circle diameter curve has a maximum portion (38).

3. The hub body according to any one of the preceding claims, characterized in that the maximum portion (38) of the root circle diameter curve (36) is arranged in the protruding outer jacket portion (64).

4. The hub body according to any one of the preceding claims, characterized in that the first hub end face (20) has a first hub end surface (26), the second hub end face (22) has a second hub end surface (44), wherein the maximum portion (38): · is arranged at a distance from the first hub end surface (26) and / or the second hub end surface (44), and / or · is arranged at or off - center between the first hub end surface (26) and the second hub end surface (44).

5. The hub body according to claim 4, characterized in that a first root circle end diameter (50) arranged in the first hub end surface (26) is equal to or different from a second root circle end diameter (52) arranged in the second hub end surface (44).

6. The hub body according to claim 4 or 5, characterized in that the root circle diameter curve (36) from the first hub end surface (26) to the second hub end surface (44) is designed to be continuous and / or differentiable.

7. The hub body according to any one of claims 4 to 6, characterized in that the protruding outer jacket portion (64) extends from the first hub end surface (26) to the second hub end surface (44).

8. The hub body according to any one of claims 1 to 6, characterized in that the root circle diameter curve (36) has a first recess (54), and the first recess has a preferably constant first cavity radius (56).

9. The hub body according to claim 8, characterized in that the root circle diameter curve (36) has a second recess (58), and the second recess has a preferably constant second cavity radius (60), wherein the first cavity radius (56) is equal to or different from the second cavity radius (60).

10. The hub body according to any one of the preceding claims, characterized in that the drive gear (28) is designed as a helical gear.

11. A compound wheel (10), in particular a compound gear (12), It has a hub body (16) according to any one of the preceding claims and an annular body (18) arranged radially outside the hub body (16), the annular body having a first axial annular body end (18a) and a second axial annular body end (18b), wherein the annular body (18) and the drive tooth part (28) are arranged to engage with each other.

12. The compound wheel according to claim 11, characterized in that the first axial annular body end (18a) and / or the second axial annular body end (18b) is arranged only on the outer jacket surface (24) of the hub body (16).

13. The compound wheel according to claim 11 or 12, characterized in that the annular body (18) has a first annular surface (40) at the first axial annular body end (18a), and the drive tooth part (28) is arranged to penetrate into the first annular surface (40).

14. The compound wheel according to any one of claims 11 to 13, characterized in that the annular body (18) has a second annular surface (48) arranged axially opposite to the first annular surface (40) at the second axial annular body end (18b), wherein the drive tooth part (28) is arranged to penetrate into the second annular surface (48).

15. A steering unit for a motor vehicle, which has a compound wheel (10) according to any one of the preceding claims.

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