Shaft, hub, shaft-hub connection and electrical actuator

Abstract

shaft longitudinal axis (12); shaft side (lateral surface) (14); A shaft (10) for converting torque and / or axial force, comprising a shaft end (16), wherein the shaft side (14) has at least one recess (18) having an axial recess wall (18) and a radial recess wall (22) adjacent to the axial recess wall (20), wherein the radial recess wall (22) includes a first wall end (36) and a second wall end (38), and the at least one recess (18) is axially open in the direction of the wall end (16), wherein the radial recess wall (22) has a recess radius (28) such that the radial recess wall (22) has a recess arc shape extending away from the shaft longitudinal axis (12) in at least cross-sectional area, and a hub (48) including a hub longitudinal axis (50). In this, at least one hub arc portion (56) is characterized by having a convex hub arc shape oriented toward the hub longitudinal axis (50), and provides an electric actuator comprising a shaft-hub connection (68) including a shaft (10) and a hub (48), and a shaft-hub connection (68).

Description

Technology Field

[0001] The present invention relates to a shaft, a hub, a shaft-hub connection, and an electric actuator for transitioning torque and / or axial force. Background Technology

[0002] Numerous shaft-hub connections for various applications are known in the prior art. For example, in the field of electric actuators, such as electric brake boosters, it is particularly known to connect a shaft formed as a spindle at one end to a hub formed as a plate in order to fix the spindle to a mechanical member that moves relative to the spindle. Thus, connecting the spindle to the plate must be capable of converting not only the axial force acting along the longitudinal axis of the spindle but also the torque acting around the longitudinal axis of the spindle. Sometimes, there is a requirement that the corresponding shaft-hub connection must occupy only a limited space.

[0003] Until now, such connections have been realized through welding the spindle to the plate. However, for such a connection to be possible, both parts must be designed to be weldable from a material perspective. Nevertheless, the corresponding materials or surfaces have disadvantages in terms of corrosion resistance. Additionally, since oil residue generally negatively affects welding characteristics, the parts must be free of oil residue before welding is applied.

[0004] Accordingly, the object of the present invention is to provide a reliable and robust connection between a shaft and a hub that has small space requirements and is cost-effective to manufacture. Additionally, the object of the present invention is to provide a shaft and a hub for such a connection. Furthermore, the object of the present invention is to provide a high-quality electric actuator that requires a small installation space and is cost-effective to manufacture. The problem to be solved

[0005] According to the present invention, the above objective is solved by a shaft having the features of claim 1, a hub having the features of claim 10, a shaft-hub connection having the features of claim 15, and an electric actuator having the features of claim 19. means of solving the problem

[0006] Preferred embodiments of the present invention are provided in dependent claims.

[0007] A shaft according to the present invention for converting torque and / or axial force comprises a shaft longitudinal axis, a shaft lateral surface, and a shaft end. The shaft lateral surface comprises at least one recess having an axial recess wall and a radial recess wall adjacent to the axial recess wall. The axial recess wall may be particularly suitable for converting axial force. The radial recess wall may be particularly suitable for converting torque acting around the longitudinal axis of the shaft. The radial recess wall is preferably positioned parallel to the longitudinal axis of the shaft. On the other hand, the axial recess wall is preferably positioned perpendicular to the radial recess wall. The radial recess wall is preferably positioned adjacent to the axial recess wall in such a way that the shaft-side transition radius is positioned at the transition from the radial recess wall to the axial recess wall, which may particularly serve to reduce notch stress.

[0008] The radial recess wall includes a first wall end and a second wall end. Each of the wall ends is preferably formed by the radial recess wall and the cut line on the side of the shaft.

[0009] The at least one recess is axially open in the direction of the shaft end. Accordingly, the corresponding axial opening is preferably positioned opposite the axial recess wall. Accordingly, the shaft coming axially from the direction of the shaft end preferably does not have a shaft portion that at least partially covers the at least one recess. Preferably, a hub having a member coupled to the at least one recess can be pushed from the end of the shaft onto the shaft until the coupling member is seated on the axial recess wall.

[0010] Unless otherwise noted, the terms "axial" and "radial" preferably refer to the shaft longitudinal axis and / or hub longitudinal axis.

[0011] According to the present invention, the radial recess wall has a recess radius such that it has a recess arc shape extending away from the longitudinal axis of the shaft in at least cross-sectional area. Accordingly, the radial recess wall may be particularly advantageously suited for diverting torque acting around the longitudinal axis of the shaft. Due to the concave arc shape of the recess extending away from the longitudinal axis of the shaft, it is preferable that at least one recess has a trough shape when viewed from the surface of the shaft. In particular, the radial recess wall may deviate from an imaginary straight line connecting the first wall end and the second wall end due to the concave arc shape of the recess between the first wall end and the second wall end. The formation of the radial recess wall according to the present invention is preferably not inconsistent with the radial recess wall being formed partially as a straight line. For example, the radial recess wall may include a plurality of straight lines that can be connected to each other by arc-shaped portions having an angular offset from one another. The angular offset may be within the range between 90° and 180°.

[0012] In a preferred embodiment of the present invention, the recess arc shape of the radial recess wall extends from the first wall end to the second wall end and / or the recess radius is formed variably. When the recess arc shape of the radial recess wall extends from the first wall end to the second wall end, the entire radial recess wall is preferably arc-shaped, so that the radial recess wall has no straight portion in the direction from the first wall end to the second wall end. If the recess radius is formed variably, the recess radius is preferably not constant. Therefore, the radial recess wall is preferably not bent uniformly. Due to the variable formation of the recess radius, torque transfer through the radial recess wall can be made more uniform, and thus, stress on the contact surface, particularly the one involved, can be reduced. In particular, it is preferable to form the recess radius larger than the outer diameter of the shaft.

[0013] Particularly preferably, the recess arc shape of the radial recess wall corresponds to at least one part of a hypotrochoid. It is desirable that this be a contour that can be simply and quickly generated and capable of uniform torque transition. Here and below, the hypotrochoid is understood to mean the path described by a point placed on the circle when this circle rolls over another circle called the so-called base circle. Here, the point considered is outside or inside the rolled circle.

[0014] In parametric representation, a hypotrochoid can be described by the following set of formulas.

[0015]

[0016]

[0017] Here, R is the radius of the base circle, r is the radius of the rolled circle, and d is the distance from the center of the rolled circle to the point. Thus, the parameter d can be viewed as a measure of eccentricity. The R / r ratio is preferably chosen to be a natural number. In particular, in this case, the ratio may represent the number of corners of the so-called hypotrochoid. Preferably, the R / r ratio is 3 or greater. Particularly preferably, the R / r ratio is 4.

[0018] The hypotrochoid center of the hypotrochoid is preferably positioned on the longitudinal axis of the shaft.

[0019] Accordingly, the R / r ratio preferably corresponds to the number of recesses. Thus, the recesses can be distributed uniformly and symmetrically along the circumference of the shaft. The shaft can be formed such that the edge of the hypotrochoid is positioned outside the shaft. Accordingly, in the corresponding embodiment of the present invention, the edge is not directly depicted as a recess arc shape.

[0020] In another embodiment of the present invention, the shaft side is provided with a spindle tooth system having at least one spindle tooth. Preferably, the at least one spindle tooth rotates helically around the shaft along the longitudinal axis of the shaft. Thus, the shaft can serve as, for example, a spindle of a spindle drive device.

[0021] At least one axial recess wall among the at least one recess may be formed at least partially from the cut surface of the at least one spindle tooth. In this way, the at least one spindle tooth may end within the axial recess wall. In this way, a particularly advantageous transition of axial force between the shaft and the member disposed in the at least one recess may be performed.

[0022] The cut surface of the at least one spindle tooth is preferably spaced apart from the first wall end and / or the second wall end of the radial recess wall. The wall end is preferably formed at the point where the radial recess wall emerges from the shaft along the recess arc shape each time. The arrangement of the cut surface preferably depends particularly on the torque transferred by the shaft. Torque transfer along the radial recess wall generally occurs primarily in the region of at least one of the wall ends. In particular, depending on the direction of rotation, torque transfer may be performed mainly in the region of the first wall end or the second wall end.

[0023] As described above, the transfer of axial force from or to the shaft is generally performed primarily through the cut surface of at least one spindle tooth. By positioning the cut surface of the at least one spindle tooth at the first wall end and / or the second wall end, mechanical stress on the shaft can be distributed as uniformly as possible in the area of ​​the recess. According to experience, three application cases are actually known in which the shaft can be adjusted, particularly by positioning the cut surface of the at least one spindle tooth with respect to the wall end.

[0024] In the first application example, particularly, when the shaft rotates, torque conversion may occur substantially only in the first rotational direction and may therefore occur mainly in the region of the first wall end. In this case, an embodiment of the shaft is preferably used in which the cut surface of the at least one spindle tooth is spaced apart from the first wall end and positioned in the region of the second wall end.

[0025] In the second application example, particularly when the shaft rotates, torque conversion may occur substantially only in the second rotational direction and may therefore occur mainly in the region of the second wall end. In this case, an embodiment of a shaft is preferably used in which the cut surface of the at least one spindle tooth is spaced apart from the second wall end and positioned in the region of the first wall end.

[0026] In the third application example, particularly when the shaft rotates, torque conversion can occur in both rotational directions and may primarily occur in the regions of the first wall end and the second wall end. In this case, an embodiment of the shaft is preferably used in which the cut surface of the at least one spindle tooth is spaced apart from the first wall end and the second wall end. In this case, the cut surface of the at least one spindle tooth is preferably positioned in the center between the first wall end and the second wall end.

[0027] In a preferred embodiment of the present invention, the at least one recess comprises a plurality of recesses, the at least one spindle tooth comprises a plurality of spindle teeth, the number of recesses corresponds to the number of spindle teeth, and the axial recess wall of each recess is formed at least partially from the cut surface of one of the spindle teeth. Through this, the conversion of torque and / or axial force can be evenly distributed around the shaft. Particularly preferably, the shaft has four spindle teeth and four recesses, which are preferably evenly distributed along the circumference of the shaft.

[0028] It is preferable that an edge be positioned between the axial recess wall and the shaft end. After placing a member in the at least one recess, the edge can be deformed to thereby fix the member axially. Preferably, the edge is formed in a ring shape, particularly circular. The edge is preferably not interrupted along its circumference. The shaft is particularly preferably formed with a central bore along the longitudinal axis of the shaft. Thus, the edge can be formed by an additional recess on the side of the shaft. Particularly preferably, the outer diameter of the edge is smaller than the maximum outer diameter of the shaft. Thus, the shaft can be manufactured simply and inexpensively from a rod material. The shaft end is formed by the free front side of the edge. The edge can be cut by at least one recess.

[0029] A hub according to the present invention comprises a hub longitudinal axis, a hub opening extending along the hub longitudinal axis, and an inner wall radially restricting the hub opening. The inner wall has at least one hub arc portion having a hub arc radius such that at least one hub arc portion has a convex hub arc shape oriented toward the hub longitudinal axis. Accordingly, particularly uniform torque transfer can be performed on a member disposed in the hub opening. Due to the convex hub arc shape oriented toward the hub longitudinal axis, the hub is formed in a convex shape. The hub opening is preferably completely enclosed by a plane orthogonal to the hub longitudinal axis. The hub is preferably formed in the shape of a plate.

[0030] Particularly preferably, the hub arc radius is formed uniformly. Accordingly, the hub arc radius can be manufactured particularly simply, particularly in a stamping process. Alternatively, the hub arc radius can be formed variably. In particular, the hub arc shape of the at least one hub arc portion may correspond to at least one portion of a hypotrochoid. The hub arc shape may correspond particularly to the recess arc shape of the hub described above. Accordingly, it may be particularly easy to place the hub on the shaft. Additionally, the hub arc shape may include a plurality of straight lines that can be connected to each other through the arc portion, for example, having an angular offset from each other. Here, the angular offset may be between 90° and 180°.

[0031] The above at least one hub arc portion preferably includes a first hub arc end and a second hub arc end, each of which is adjacent to an undercut. Accordingly, a predetermined adjacency of the at least one hub arc portion to a member disposed in the hub opening can be realized. The undercut may each be formed by an undercut bore. The undercut bores are preferably surrounded by the hub opening and each may be concavely oriented toward the hub longitudinal axis. The undercut radius of each undercut is preferably significantly smaller than the hub arc radius.

[0032] At least one hub arc portion at the first hub arc end may include a tangential transition portion for an undercut adjacent to the first hub arc end and / or at least one hub arc portion at the second hub arc end may include a tangential transition portion for an undercut adjacent to the second hub arc end. Through continuous tangential transitions, a particularly large contact surface can be obtained in the member placed in the hub bore. Such continuous tangential transitions are preferably formed such that the tangents applied to the hub arc portion and the undercut have the same gradient when each hub arc end transitions to an adjacent undercut. In other words, the contour of the hub opening may preferably be continuously distinguishable in the transition from the at least one hub arc portion to the corresponding undercut.

[0033] When the torque acting around the hub longitudinal axis is transferred to or from the member positioned in the hub opening, the torque transfer primarily occurs in these regions, as the highest load may occur in the region of the first hub arc end or the second hub arc end. Due to this tangential transfer, the load can be distributed over a relatively wide area, so the stress applied to the hub can be kept low. By selecting a tangential continuous transfer section for the corresponding adjacent undercut among the hub arc ends, the hub can be applied to various applications. Corresponding to the applications described above with respect to the shaft, substantially three applications with respect to the hub are known, and the shaft can be adjusted by positioning at least one spindle tooth cut surface with respect to the wall end.

[0034] In the first application example, torque conversion can substantially occur only in the first rotational direction and thus occurs mainly in the region of the first hub arc end. In this case, an embodiment of a hub having a tangential continuous conversion section with respect to an undercut adjacent to the first hub arc end is preferably used.

[0035] In the second application example, torque conversion can substantially occur only in the second rotational direction and thus occurs mainly in the region of the second hub arc end. In this case, an embodiment of a hub having a continuous tangential transition section with respect to an undercut adjacent to the second hub arc end is preferably used.

[0036] In the third application example, since torque conversion can occur in both rotational directions, it mainly occurs in the regions of the first hub arc end and the second hub arc end. In this case, an embodiment of a hub may be used in which the first hub arc end has a continuous tangential transition portion with respect to an undercut adjacent to the first hub arc end, and the second hub arc end has a continuous tangential transition portion with respect to an undercut adjacent to the second hub arc end.

[0037] Alternatively, the undercut radius may be selected to be smaller and / or the undercut may be positioned further away from the hub longitudinal axis to extend at least one hub arc portion in the direction of the first hub arc end and the direction of the second hub arc end and to divert a more uniform load distribution.

[0038] Preferably, the at least one hub arc portion comprises a plurality of hub arc portions uniformly arranged circumferentially around the hub longitudinal axis of the hub opening. Accordingly, particularly when switching torque, the load of the hub can be uniformly distributed around the longitudinal axis of the hub. Preferably, the hub arc portions are formed in the same manner. If there are three or more hub arc portions, the hub opening may have a polygonal shape with an undercut at each edge. Particularly preferably, the hub has four hub arc portions.

[0039] The shaft-hub connection according to the present invention comprises a previously described shaft and a previously described hub. The hub is positioned on the shaft in the following manner.

[0040] · The above at least one hub arc portion is disposed within the above at least one recess, and

[0041] · The inner wall of the hub opening is positioned in the region of at least one hub arc portion of the radial recess wall facing the at least one recess, and

[0042] · The first side of the above hub is operatively connected to the axial recess wall of the at least one recess.

[0043] Accordingly, the at least one hub arc portion may form a member disposed in the at least one recess. Likewise, the shaft may form a member disposed in the hub opening.

[0044] Preferably, the hub is positioned on the shaft in such a way that the hub longitudinal axis is aligned along the shaft longitudinal axis and is positioned on the shaft longitudinal axis. In particular, between the inner wall of the hub opening and the radial recess wall, an operative connection may exist in such a way that the inner wall and the radial recess wall are at least partially adjacent to each other. Thus, force or torque may be transferred between the inner wall and the radial recess wall.

[0045] The axial recess wall of at least one of the above-mentioned recesses and the first side of the hub are operatively connected to the hub to axially secure the hub to the shaft. This operative connection is preferably formed so that the first side rests directly on the axial recess wall.

[0046] In addition to the first side, the hub preferably has a second side, particularly preferably a second side facing the first side. Each of these sides may be formed as a surface of the hub adjacent to the inner wall of the front side. Due to the front side arrangement, the first side and the second side are preferably aligned substantially orthogonally to the longitudinal axis of the hub. The edge between the inner wall and the first side may preferably have a hub-side turning radius corresponding to the shaft-side turning radius. Accordingly, the hub can be easily mounted on the shaft.

[0047] The above at least one hub arc portion preferably corresponds to at least one recess in terms of number and arrangement. Preferably, the hub has the same number of hub arc portions as the shaft of the recess. Due to the arrangement of the hub arc portions corresponding to the arrangement of the recess, exactly one hub arc portion can be placed in each recess. Particularly preferably, the hub has four recesses, and the hub has four hub arc portions.

[0048] In a preferred embodiment of the shaft-hub connection, the shaft has an oversize relative to the hub in the region of the first hub arc end and the region of the second hub arc end of the at least one recess, and the shaft has a clearance in the center region of the at least one hub arc portion positioned between the first hub arc end and the second hub arc end. Accordingly, a clearance-free connection between the hub and the shaft is possible, particularly at the point where a significant portion of torque transition occurs, while simultaneously maintaining a low required assembly force.

[0049] In an alternative embodiment, the shaft-hub connection may be formed such that the shaft has a clearance in the region of the first hub arc end and the region of the second hub arc end of the at least one recess, and the shaft has an oversize relative to the hub in the center region of the at least one hub arc portion positioned between the first hub arc end and the second hub arc end.

[0050] Preferably, the shaft-hub connection is formed such that the edge of the shaft is deformed radially outward and axially in the direction of the hub, preferably flanged, so that a second side of the hub positioned opposite the first side is operatively connected to the deformed edge. Accordingly, the hub can be secured to the shaft on both axial sides. The operative connection between the second side and the deformed edge is preferably formed such that the deformed edge is directly adjacent to the second side, particularly preferably.

[0051] A method for creating a shaft-hub connection having the above-deformed edge may include the following steps:

[0052] · Step of providing the aforementioned shaft having the aforementioned edge,

[0053] · The step of providing the hub described earlier,

[0054] · The above hub,

[0055] ° The above at least one hub arc portion is placed in at least one recess, and

[0056] ° The inner wall of the hub opening is positioned in the region of at least one hub arc portion of the radial recess wall facing at least one recess, and

[0057] ° A step of positioning the first side of the hub on the shaft so as to be operatively connected to the axial recess wall of at least one recess,

[0058] In particular, a step of forming an edge that protrudes axially and radially outwardly and axially in the direction of the hub beyond the hub by flanging, in particular by a tumbling process or a rolling process, and

[0059] · A step of terminating the forming as soon as the above edge is adjacent to the above second side.

[0060] By deforming an edge that protrudes axially, radially outwardly, and axially toward the hub beyond the hub, the air-filled space positioned between the inner wall of the hub and the shaft can be at least partially filled with the material of the shaft. Accordingly, the connection between the shaft and the hub can be improved. The deformation process can be implemented in a short production time using a tumbling process or a rolling process. Preferably, since the strength of the deformed edge may decrease as the deformation process continues, the deformation is terminated immediately after the edge is adjacent to the second side. Effects of the invention

[0061] The electric actuator according to the present invention includes the previously described shaft-hub connection. The electric actuator may be formed, for example, as an electric brake booster, particularly for vehicles. Such a brake booster is used particularly in electric-driven vehicles, such as electric vehicles. Brief explanation of the drawing

[0062] Hereinafter, the present invention will be described in more detail using embodiments and with reference to the attached drawings. FIG. 1a is a first perspective view of a shaft according to a first embodiment. FIG. 1b is a second perspective view of the embodiment shown in FIG. 1. FIG. 2a is a plan view of a shaft according to a second embodiment. FIG. 2b is a first side view of the embodiment shown in FIG. 2a. FIG. 2c is a second side view of the embodiment shown in FIG. 2a. FIG. 3 is a plan view of a shaft according to a third embodiment. FIG. 4 is a plan view of a shaft according to the fourth embodiment. FIG. 5a is a perspective view of a hub according to a first embodiment. FIG. 5b is a plan view illustrating the embodiment shown in FIG. 5a according to the cut surface AA. FIG. 5c illustrates an embodiment illustrated in FIG. 5a according to the cut surface AA illustrated in FIG. 5b. FIG. 6 is a plan view of a hub according to a second embodiment. FIG. 7 is a plan view of a hub according to a third embodiment. FIG. 8a is a first perspective view illustrating an example of a shaft-hub connection. FIG. 8b is a second perspective view illustrating an embodiment shown in FIG. 8a. FIG. 8c is a side view of the embodiment shown in FIG. 8a. FIG. 8d is a plan view illustrating the embodiment shown in FIG. 8a according to cut planes AA, BB, and CC. FIG. 8e is a cross-sectional view illustrating the embodiment shown in FIG. 8a having a detailed portion (Y) according to the cut line AA shown in FIG. 8d. FIG. 8f is an enlarged view showing the detailed part (Y) shown in FIG. 8e. FIG. 8g is a cross-sectional view illustrating the embodiment shown in FIG. 8a along the cutting line BB indicated in FIG. 8d. FIG. 8h is a cross-sectional view illustrating the embodiment shown in FIG. 8a having a detailed portion (Z) according to the incision line CC shown in FIG. 8d. FIG. 8i is an enlarged view showing the detailed part (Z) shown in FIG. 8h. Specific details for implementing the invention

[0063] FIGS. 1a through 8i illustrate various aspects of various embodiments. The same and functionally identical

[0064] The same reference numerals are used for the components. For clarity, all reference numerals are used in all drawings.

[0065] FIGS. 1A and 1B illustrate a first embodiment of a shaft (10) for converting torque and / or axial force. The shaft (10) comprises a shaft longitudinal axis (12), a shaft lateral surface (14), and a shaft end (16). The shaft lateral surface (14) has four recesses (18). Each of the recesses (18) has an axial recess wall (20) and a radial recess wall (22) adjacent to the axial recess wall (20), and the radial recess wall (22) each has a first wall end (36) and a second wall end (38). The axial recess wall (20) is particularly suitable for converting axial force, but the radial recess wall (22) is provided particularly for converting torque acting around the shaft longitudinal axis (12).

[0066] Each of the above radial recess walls (22) is positioned parallel to the shaft longitudinal axis (12). The axial recess wall (20) is positioned perpendicular to the corresponding radial recess wall (22). The radial recess wall (22) is adjacent to the axial recess wall (20) in such a way that the shaft-side transition radius (24) is positioned at the transition point from each of the radial recess walls (22) to the corresponding axial recess wall (20), which can particularly serve to reduce notch stress.

[0067] In the direction of the shaft end (16), each recess (18) is axially open. The shaft (10) coming axially from the direction of the shaft end (16) does not have a shaft portion that partially covers the recess (18) (see particularly FIG. 1b). Preferably, the hub (48) shown in FIG. 5a through 7 can be pushed from the shaft end (16) over the shaft (10) until the hub (48) is seated on the axial recess wall (20).

[0068] Each of the above radial recess walls (22) has a recess radius (28), and each of the above radial recess walls (22) has a concave recess arc shape extending away from the shaft longitudinal axis (12). Due to the concave recess arc shape extending away from the shaft longitudinal axis (12), the recess (18) is formed in a trough shape when viewed from the side of the shaft (14).

[0069] The recess radius (28) is formed to be variable whenever the recess arc shape of the radial recess wall (22) extends from the first wall end (36) to the second wall end (38) and the recess radius (28) is formed to be variable. Here, the recess radius (28) is formed to be variable in such a way that the recess arc shape of the radial recess wall (22) corresponds to the cross-section of each hypotrochoid. The recess arc shape of all recesses (18) of the shaft (10) corresponds to a portion of a single virtual hypotrochoid. This applies to each illustrated embodiment. Here, the center of the virtual hypotrochoid of the hypotrochoid is positioned on the longitudinal axis (12) of the shaft. Thus, the recesses (18) can be distributed evenly and symmetrically along the circumference of the shaft (10). The shaft (10) is formed such that the corners of the hypotrochoid are positioned outside the shaft side (14) of the shaft (10) so that the corners are not directly depicted as recessed arc shapes. However, the number of corners corresponds to the number of recesses (18) of the shaft (10). The embodiment illustrated in FIGS. 1a through 7 is based on a hypotrochoid having four corners.

[0070] In each embodiment illustrated in FIGS. 1a through 7, the shaft side (14) has a spindle tooth system having four spindle teeth (32). The spindle teeth (32) rotate spirally around the shaft (10) along the shaft longitudinal axis (12).

[0071] In particular, the drawings in FIG. 1b and FIG. 2c illustrate that each axial recess wall (20) is formed at least cross-sectionally by a cut surface (34) of one of the spindle teeth (32). Each spindle tooth ends at one of the axial recess walls (20). Thus, the number of recesses (18) corresponds to the number of spindle teeth (32).

[0072] The wall ends (36, 38) are preferably formed at points where each radial recess wall (22) emerges from the shaft (10) along the recess arc shape. In the embodiment illustrated in FIGS. 1a to 2c, the cut surface (34) of each spindle tooth (32) is spaced apart from the first wall end (36) and positioned in the area of ​​the second wall end (38). Accordingly, the exemplary embodiment illustrated in FIGS. 1a to 2c is optimized for a first application case in which torque conversion occurs substantially only in the first rotational direction (40) and thus mainly occurs in the area of ​​the first wall end (36).

[0073] On the other hand, the embodiment of the shaft (10) illustrated in FIG. 3 is optimized for a second application case in which torque conversion occurs substantially mainly in the region of the second wall end (38). This may be, for example, a case where torque is substantially converted to the second rotational direction (42). The cut surface (34) of the spindle tooth (32) is spaced apart from each second wall end (38) and positioned in the region of each first wall end (36).

[0074] In a third intended application of the embodiment of the shaft (10) shown in FIG. 4, torque conversion can be performed in both directions of rotation and thus primarily in the regions of each first wall end (36) and each second wall end (38). Accordingly, the cut surface (34) of the spindle tooth is spaced apart from each first wall end (36) and each second wall end (38) and is positioned at the center between each first wall end (36) and each second wall end (38).

[0075] Due to the arrangement of the cut surface (34) described in various embodiments, the mechanical stress on the shaft (10) can be distributed as uniformly as possible in the area of ​​the recess (18).

[0076] In particular, as can be clearly seen in FIGS. 1a and 2b, an edge (44) is positioned between the axial recess wall (20) and the shaft end (16). The shaft (10) has a central bore (46) along the shaft longitudinal axis (12). The edge (44) is formed by an additional recess on the shaft side (14), so that the edge (44) is circular and uninterrupted. The shaft end (16) is formed by the free front side of the edge (44). The embodiment illustrated in FIGS. 2a through 2c differs from the embodiment illustrated in FIGS. 1a through 1b in that the edge (44) can be cut by the recess (18).

[0077] FIGS. 5a through 5c illustrate a first embodiment of a hub (48). The hub (48) comprises a hub longitudinal axis (50), a hub opening (52) extending along the hub longitudinal axis (50), and an inner wall (54) that radially limits the hub opening (52). The inner wall comprises four hub arc portions (56), each having a constant hub arc radius (58), wherein each hub arc portion (56) has a convex hub arc shape facing the hub longitudinal axis (50). Due to the convex hub arc shape facing the hub longitudinal axis (50), each hub arc portion (56) is formed in a belly-convex shape when viewed from the hub longitudinal axis (50). The hub opening (52) is preferably completely enclosed by a plane orthogonal to the hub longitudinal axis (50). The hub (48) is preferably formed in the shape of a plate.

[0078] Each of the above hub arc portions (56) has a first hub arc end (60) and a second hub arc end (62), each of the above hub arc ends (60, 62) is adjacent to an undercut (64), and each undercut (64) is formed by an undercut bore. The other hub bore ends (60, 62) of the hub arc portions (56) that are connected to each other in a circumferential direction around the hub longitudinal axis (50) are each bounded on the same undercut (64). Each of the above undercuts (64) is concavely oriented toward the hub longitudinal axis (12). The undercut radius (65) of each of the above undercuts (64) is preferably significantly smaller than each hub arc radius (58).

[0079] The hub arc portion (56) of the embodiment illustrated in FIGS. 5a to 7 is uniformly arranged in the circumferential direction of the hub opening (52) around the hub longitudinal axis (50) and formed with the same shape. Accordingly, a square shape having an undercut (65) at each corner is formed.

[0080] In particular, as can be seen in FIG. 5b, each hub arc portion (56) has a tangential continuous transition portion (66) on the first hub arc end (60) up to an undercut (64) adjacent to each first hub arc end (60).

[0081] According to the application example described above with respect to the shaft (10), the hub (48) can be applied to various applications by selecting which of the hub arc ends (60, 62) has a tangential transition portion (66) at a correspondingly adjacent undercut (64). The embodiment of the hub (48) shown in FIGS. 5a to 5c is optimized for a first application example in which torque transition occurs substantially only in the first rotational direction (40) and mainly occurs in the region of the first hub arc end (60).

[0082] FIG. 6 illustrates an embodiment of a hub (48) intended for a second application case in which torque conversion occurs substantially only in the second rotational direction (42) and mainly in the region of the second hub arc end (62). Here, each second hub arc end (62) has a tangential conversion portion (66) for each adjacent undercut (64).

[0083] The embodiment of the hub (48) shown in FIG. 7 is formed for a third application case in which torque conversion occurs in both rotational directions (40, 42) and mainly in the regions of the first hub arc end (60) and the second hub arc end (62). Here, the undercut radius (65) is selected to be smaller, and the undercut (64) is positioned further from the hub longitudinal axis (50) than in the embodiments shown in FIG. 5a through 6.

[0084] FIGS. 8a through 8i illustrate a shaft-hub connection (68) comprising a shaft (10) illustrated in FIGS. 2a through 2b and a hub (48) illustrated in FIGS. 5a through 5c. As can be seen in FIGS. 5a through 5c, the hub (48) has the same number of hub arc portions (56) as the shaft (10) in the recess (18). Here, the hub (48) is positioned on the shaft (10) such that each hub arc portion (56) is positioned in exactly one recess (18). In particular, as can be seen in FIG. 8f, the inner wall (54) of the hub opening (52) is positioned in the area of ​​the hub arc portion (56) of the radial recess wall (22) facing each recess (18). Additionally, the first side (70) of the hub (48) is operatively connected to the axial recess wall (20) of the recess (18), and the first side (70) is seated directly on the axial recess wall (20) (see Fig. 8e in particular).

[0085] The hub (48) is positioned on the shaft (10) in such a way that the hub longitudinal axis (50) is aligned along the shaft longitudinal axis (12) and is positioned on the shaft longitudinal axis (12).

[0086] In addition to the first side (70), the hub has a second side (72) opposite the first side (70) and clearly visible in FIG. 8a. The sides (70, 72) are adjacent to the inner wall (54) of the hub (48) on the front side and are aligned perpendicularly to the hub longitudinal axis (50). The edge between the inner wall (54) and the first side (70) has a hub-side turning radius (74) (see also FIG. 5a and FIG. 5c) corresponding to the shaft-side turning radius (24).

[0087] The shaft (10) has an oversize (76) compared to the hub (48) in the area of ​​the first hub arc end (60) and the area of ​​the second hub arc end (62), which can be seen in the overview of FIGS. 8d, 8h and 8i. There is a gap (78) in the central area of ​​the hub arc portion (56) between each first hub arc end (60) and each second hub arc end (62). This is particularly evident when viewed together in FIGS. 8d, 8e and 8f. This enables a gapless connection between the hub (48) and the shaft (10), while simultaneously keeping the required assembly force low.

[0088] As illustrated in FIG. 8a, the shaft-hub connection (68) is formed such that the edge (44) of the shaft (10) is deformed radially outward and axially in the direction of the hub (48), and a second side (72) of the hub having the deformed edge (44) is formed. The axial fixation of the hub (48) is operatively connected to the shaft (10). The deformed edge (44) is positioned directly above the second side (72).

[0089] The shaft-hub connection (68) can be created by first providing the shaft (10) and the hub (48) and then placing the hub (48) on the shaft (10) as described above. In this state, before deformation of the edge (44) occurs, the shaft-hub connection is illustrated in FIGS. 8C through 8I. The edge (44) protruding axially beyond the hub (48) can be formed to be deformed radially outward and axially in the direction of the hub (48), particularly flanged, by, for example, a tumbling process or a rolling process. As soon as the edge (44) is placed on the second side (72), it is preferable to stop the deformation so as not to damage the strength of the deformed edge (44). The state in which the edge is seated on the second side (72) is illustrated in FIG. 8A. Explanation of the symbols

[0090] Reference Number List 10 shafts 12 shaft longitudinal axis 14 Shaft Side 16 shaft end 18 Recesses 20 axial recess walls 22 Radial recess wall 24 Shaft-side switching radius 28 Recess Radius 32 spindle teeth 34 Incision surface 36 First wall end 38 Second wall end 40 First rotation direction 42 Second rotation direction 44 edge 46 central complement 48 Hubs 50 hub breeding stock 52 hub openings 54 inner wall 56 Hub arc section 58 Hub arc radius 60 1st hub arc end 62 Second hub arc end 64 undercut 65 undercut radius 66 Tangential direction switching section 68 Shaft-hub connection 70 1st side 72 Second side 74 Hub-side switching radius 76 Oversized 78 Shortstops

Claims

Claim 1 shaft longitudinal axis (12); shaft side (lateral surface) (14); A shaft (10) for converting torque and / or axial force, comprising a shaft end (16), wherein the shaft side (14) has at least one recess (18) having an axial recess wall (18) and a radial recess wall (22) adjacent to the axial recess wall (20), wherein the radial recess wall (22) includes a first wall end (36) and a second wall end (38), and the at least one recess (18) is axially open in the direction of the shaft end (16), wherein the radial recess wall (22) has a recess radius (28) such that the radial recess wall (22) has a recess arc shape extending away from the shaft longitudinal axis (12) in at least cross-sectional area, and the shaft side (14) has at least one spindle tooth (32). A shaft (10) having a spindle tooth system, wherein at least one axial recess wall (20) of at least one recess (18) is formed at least partially from the cutting surface (34) of at least one spindle tooth (32). Claim 2 A shaft (10) characterized in that, in claim 1, the recess arc shape of the radial recess wall (22) extends from the first wall end (36) to the second wall end (38) and / or the recess radius (28) is formed variably. Claim 3 A shaft (10) characterized in that, in claim 1 or 2, the recess arc shape of the radial recess wall (22) corresponds to at least one part of a hypotrochoid. Claim 4 In paragraph 3, the shaft (10) is characterized in that the hypotrochoid center of the hypotrochoid is positioned on the shaft longitudinal axis (12). Claim 5 delete Claim 6 delete Claim 7 A shaft (10) characterized in that, in claim 1 or 2, the cut surface (34) of the at least one spindle tooth (32) is spaced apart from the first wall end (36) and / or the second wall end (38) of the radial recess wall (22). Claim 8 A shaft (10) characterized in that, in claim 1 or 2, the at least one recess (18) comprises a plurality of recesses (180), the at least one spindle tooth (32) comprises a plurality of spindle teeth (32), the number of recesses (18) corresponds to the number of spindle teeth (32), and the axial recess wall (20) of each recess (18) is formed at least partially from a cut surface (34) of one of the spindle teeth (32). Claim 9 A shaft (10) characterized in that, in claim 1, an edge (44) is disposed between the axial recess wall (20) and the shaft end (16). Claim 10 delete Claim 11 delete Claim 12 delete Claim 13 delete Claim 14 delete Claim 15 In a shaft-hub connection (68) comprising a shaft (10) and a hub (48) according to claim 1, the hub (48) comprises: a hub longitudinal axis (50); and a hub opening (52) extending along the hub longitudinal axis (50). A shaft-hub connection (68) comprising an inner wall (54) that radially restricts the hub opening (52), wherein the inner wall (54) comprises at least one hub arc portion (56) having a hub arc radius (58) such that at least one hub arc portion (56) has a convex hub arc shape toward the hub longitudinal axis (50), and wherein the hub (48) is positioned such that the at least one hub arc portion (56) is disposed within the at least one recess (18), and the inner wall (54) of the hub opening (52) is positioned in the region of the at least one hub arc portion (56) of the radial recess wall (22) toward the at least one recess (18), and the first side (70) of the hub (48) is positioned on the shaft (10) so as to be operatively connected to the axial recess wall (20) of the at least one recess (18). Claim 16 In item 15, the shaft-hub connection (68) is characterized in that the above-mentioned at least one hub arc portion (56) corresponds to at least one recess (18) in terms of number and arrangement. Claim 17 A shaft-hub connection (68) characterized in that, in claim 15, the shaft (10) has an oversize (76) compared to the hub (48) in the area of ​​the first hub arc end (60) and the area of ​​the second hub arc end (62) of the at least one recess (18), and the shaft (10) has a clearance (78) relative to the hub (48) in the central area positioned between the first hub arc end (60) and the second hub arc end (62) of the at least one hub arc portion (56). Claim 18 A shaft-hub connection according to claim 9, wherein, in claim 15, the edge (44) of the shaft (10) is deformed radially outward and axially in the direction of the hub (48) and is operatively connected to the edge (44) on which the second side (72) of the hub (48) is formed and which is positioned opposite the first side (70). Claim 19 An electric actuator having a shaft-hub connection according to paragraph 15.

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