steering gear

Abstract

The invention relates to a steering gear (1) for a vehicle, comprising: - a drive interface (2) configured to be driven by a drive unit (3), wherein the drive interface (2) is rotatable about a rotary axis (4), - an output interface (5) designed to perform a steering movement, - a motion converter (6) configured to convert the rotary motion of the drive interface (2) into the steering motion, wherein the motion converter has a transmission element (6.1) configured to receive the rotary motion of the drive interface (2), and - a coupling element (7) that is provided between the drive interface (2) and the motion converter (6), and that couples the drive interface (2) to the motion converter (6) in such a way that the rotary motion of the drive interface (2) can be transmitted to the motion converter (6), wherein the coupling element (7) is designed to be deformed in the event of a positional deviation (X) of the transmission element (6.1) from an initial position. The invention further relates to an element for transmitting a rotary motion in a steering gear (1), a coupling element (7) for a steering gear (1) and a method for manufacturing a coupling element (7).

Description

[0001] The present invention relates to a steering gear for a vehicle, an element for transmitting a rotary motion in a steering gear, a coupling element and a method for manufacturing a coupling element. State of the art

[0002] Nowadays, steering systems are known to use a steering gear driven by a rotary drive unit. The rotational motion of the drive unit is converted into a translational motion of a tie rod. The steering gear incorporates appropriately designed gear stages for transmitting and converting the drive motion. To convert the rotational motion into a translational motion, the steering gear uses a motion converter, such as a spindle drive. This motion conversion generates high forces in the motion converter. These forces can lead to a positional deviation of the motion converter elements relative to a drive interface connected to the drive unit. Since precise and consistent alignment of the elements relative to each other is necessary on both the drive unit and the drive interface, a positional deviation of the motion converter elements, for example, can cause problems.A nut in contact with the drive interface can negatively affect the position of the drive interface. The connection between the drive unit and the drive interface can be achieved, for example, through a gear mesh, where the drive interface is designed as a gear meshing with a gear, such as a pinion, driven by the drive unit. Such a positional deviation in this gear mesh negatively impacts the contact pattern, potentially leading to tooth damage. Furthermore, it can result in undesirable noise emissions, thus degrading the NVH (noise, vibration, and harshness) characteristics of the steering gear.

[0003] While attempts exist to provide a secure connection between the independently moving parts in such a steering gear, the available solutions require complex integration. Therefore, there is a need for an improved steering gear that enables efficient steering and easy assembly. Disclosure of the invention

[0004] These and other problems, which will be mentioned in the following description or which can be recognized by a person skilled in the art, are solved by the subject matter of the independent claims. Advantageous embodiments and further developments can be found in the dependent claims and the following description as well as in the drawings.

[0005] The steering gear according to the invention for a vehicle comprises a drive interface, an output interface, a motion converter, and a coupling element. The drive interface is configured to be driven by a drive unit. The drive interface is rotatable about a rotational axis. The output interface is designed to execute a steering movement. The motion converter is designed to convert the rotational movement of the drive interface into the steering movement. The motion converter further comprises a transmission element designed to receive the rotational movement of the drive interface. The coupling element is provided between the drive interface and the motion converter and couples the drive interface to the motion converter in such a way that the rotational movement of the drive interface can be transmitted to the motion converter.The coupling element is designed to be deformed if the transmission element deviates from its initial position.

[0006] The deformation may include, in particular, a displacement and / or tilting of the coupling element.

[0007] The coupling element allows for a backlash-free or at least low-backlash connection between the drive interface and the motion converter.

[0008] The steering gear and its components are described below with respect to the axis of rotation of the drive interface. Any mention or reference to radial, circumferential, or axial direction below refers to the axis of rotation of the drive interface, unless otherwise specified.

[0009] The steering movement of the output interface can be a translational, particularly linear, movement, which is, for example, applied to the tie rods of the axle to be steered in the vehicle in which the steering gear is located. For this purpose, the output interface can have a connection to the corresponding tie rod or a part of this connection. This connection can, for example, be a moment-free connection. In particular, this connection can be a ball joint connection. The output interface can comprise the entire ball joint connection or only a part of it, such as the ball joint receptacle or the ball joint itself.

[0010] The drive interface can be configured to transmit torque to the drive unit. The connection between the drive unit and the drive interface can be designed in various ways. In particular, the connection can be configured as a gear stage, with the drive interface being a gear, especially an externally toothed gear, which meshes with a gear driven by the drive unit, for example, a pinion. Alternatively, the gear stage can be configured as a planetary gear stage, with the drive interface being configured, for example, as a planet carrier and the drive unit connected to the sun gear. Alternatively, the connection can also be configured as a belt drive, with the drive interface then being configured as a pulley or belt pulley over which the belt from the drive unit is routed.Alternatively, the drive interface can be designed to connect to a drive unit arranged coaxially to the drive interface, for example, a hollow shaft motor. This connection can be a rotationally fixed coaxial connection, corresponding to a direct drive from the drive unit to the drive interface. Alternatively, the connection can include a coaxially arranged transmission stage, such as a planetary gear, between the coaxially arranged drive unit and the drive interface, thus enabling a coaxial arrangement of the drive unit and drive interface, including the coaxial transmission.

[0011] The axis of rotation around which the drive interface is designed to rotate and the steering movement can be coaxial. The drive interface can be part of the drive unit or designed as a separate part that is mechanically connected to the drive unit.

[0012] The motion converter can generally be configured to convert the rotary motion of the drive interface into a steering motion. The motion converter can be configured as a ball screw drive. Alternatively, the motion converter can also be configured as a planetary roller screw drive or a trapezoidal screw drive. The transmission element of the motion converter is designed to receive the drive torque and / or the rotary motion of the drive interface. The transmission element can be configured as a corresponding nut, in particular as a ball screw nut, a nut for the planetary roller screw drive, or a nut for the trapezoidal screw drive. The motion converter can include an intermediate element, configured as a corresponding spindle, which is designed to be axially displaceable.The intermediate element can be connected directly or via intermediate elements to the output interface, whereby the steering movement is transferred as a translational displacement from the intermediate element to the output interface.

[0013] The conversion of the drive motion into the steering motion can generate high forces within the motion converter, potentially leading to positional deviations. These deviations can particularly affect the transmission element that receives the rotary motion of the drive interface. In other words, the transmission element can deviate from its original position and, for example, become tilted relative to the drive interface or its axis of rotation. Alternatively or additionally, the intermediate element of the motion converter can also be affected by the positional deviation. Transmission of such a positional deviation to the drive interface is prevented by the deformation of the coupling element. In other words, the positional deviation is compensated for by the deformation of the coupling element, specifically by displacement and / or tilting of the coupling element.In other words, the positional deviation is not transmitted to the drive interface due to the deformation.

[0014] Alternatively or additionally, during assembly of the steering gear, for example, when all steering gear components, such as bearing seats, are in their correct positions, a positional deviation can occur. This can be caused, in particular, by tolerances of the individual steering gear components. When the steering gear is assembled, for example, when all housing parts of a steering gear housing are joined together, manufacturing tolerances can cause the steering gear components to deviate from their nominal or initial positions. Here, too, the positional deviation occurring in the motion converter causes a deformation of the coupling element. In other words, the positional deviation is compensated for by the deformation of the coupling element. In other words, the positional deviation is not transmitted to the drive interface due to the deformation.

[0015] The coupling element is located between the drive interface and the motion converter. Specifically, the coupling element is located between the drive interface and the transmission element of the motion converter. The motion converter can be at least partially surrounded by the coupling element. The transmission element can at least partially or completely surround the coupling element. In other words, the coupling element can be located between the drive interface and the transmission element of the motion converter. This configuration of the transmission element, coupling element, and drive interface allows for nesting of these elements, resulting in a compact design.

[0016] The coupling element and the transmission element of the motion converter can be arranged concentrically and / or coaxially. This arrangement allows for a compact assembly of the steering gear. The arrangement refers to the initial position of the transmission element and the drive interface.

[0017] The advantage of the solution according to the invention lies particularly in the fact that the coupling element of the steering gear ensures a position-tolerant interaction or coupling between the drive interface and the transmission element. Furthermore, the coupling element can prevent positional deviations of the integrated parts of the steering gear during operation. Accordingly, the elements of the steering gear where positional deviations should be avoided are not affected by such deviations.

[0018] According to one embodiment, the steering gear can further comprise a drive unit that is in contact with the drive interface and configured to drive the drive interface. The drive unit can be an electric motor. The drive unit can be configured to supply the drive torque. The drive torque can serve to assist a driver with steering, e.g., for power steering, if a mechanical connection from a driver interface, such as a steering element like a steering wheel, is provided. Alternatively, the drive torque can also serve solely to perform the steering function, e.g., if the steering gear is configured for a steer-by-wire steering system. In particular, the drive torque can be used to perform steering during autonomous driving, regardless of whether a mechanical connection is present or the steering gear is configured for a steer-by-wire steering system.The steering gear is designed such that the drive interface is set in rotation by the drive torque of the drive unit. This can be achieved by directly driving the drive interface or by means of a transmission. The drive unit can be arranged essentially parallel to the output interface and connected to the output interface via the drive interface and / or the motion converter.

[0019] According to one embodiment, the coupling element can comprise a circumferentially closed section with respect to the axis of rotation, which is arranged coaxially to the axis of rotation. The section can have a conical, tubular, or sleeve-shaped body, or be designed as a conical, tubular, or sleeve-shaped body. The closed section is designed to absorb circumferential forces or the torque transmitted from the drive interface to the coupling element. Due to the circumferentially closed structure of the closed section, the coupling element is particularly rigid in this region. Therefore, torque can be transmitted circumferentially via the closed section of the coupling element. The coaxial arrangement can be in its initial position, particularly when no deformation occurs.

[0020] The closed section can have an axial extent between one-quarter and one-half of the length of the coupling element in its axial direction. In particular, the closed section can have an axial extent of one-third of the length of the coupling element in its axial direction. The longitudinal direction can be parallel to the axis of rotation. A greater axial extent represents a better force-bearing capacity of the coupling element in the circumferential direction, while a smaller axial extent reduces the installation space required for the coupling element.

[0021] According to one embodiment, the coupling element can have a wall thickness in the range of 0.7 mm to 1 mm. This enables a nested arrangement of the transmission element and the drive interface, allowing for a radially compact design with respect to the axis of rotation.

[0022] According to one embodiment, the coupling element can have a first mounting area that is rotationally fixed to the motion converter, in particular to the transmission element, and a second mounting area that is rotationally fixed to the drive interface. The mounting areas can be arranged axially opposite each other, in particular at the axial edges of the closed section. This results in a rigid and resilient structure into which forces can be introduced uniformly. Alternatively, for example to meet installation space requirements, the mounting areas can be arranged axially at the same edge of the closed section. The mounting areas can also be arranged radially on different surfaces or sides of the coupling element, should this be advantageous for reasons of installation space.

[0023] To couple the coupling element with the transmission element, the first mounting area is connected to the transmission element. The transmission element can have a corresponding mounting area for this connection.

[0024] To connect the coupling element to the drive interface, the second mounting area is connected to the drive interface. The drive interface can have a corresponding mounting area for this connection.

[0025] According to one embodiment, the first fastening area can comprise at least three tongues extending axially from the coupling element along a longitudinal axis of the coupling element and / or along the axis of rotation. In particular, the longitudinal axis can be the axis of rotation. Alternatively or additionally, the second fastening area can comprise at least three tongues extending axially from the coupling element along a longitudinal axis of the coupling element and / or along the axis of rotation. In particular, the longitudinal axis can be the axis of rotation. The extension of the tongues can be substantially along a longitudinal axis of the coupling element and / or along the axis of rotation in the axial direction, while the tongues can also extend partially in the radial direction.

[0026] The tongues each have at least one fastening structure. The tongues can be spaced regularly from each other in the circumferential direction. Three tongues, in particular exactly three tongues, e.g., spaced 120 degrees apart, or four tongues, in particular exactly four tongues, e.g., spaced 90 degrees apart, can be provided. These spacings can, for example, provide sufficient space between the tongues in a ball screw drive, especially for components for recirculating the balls.

[0027] Generally, depending on the circumferential extent of the tongues, three to six tongues can be provided per fastening area. This ensures secure and distributed force absorption by the tongues.

[0028] The coupling element may have a rounded transition to the tongues in order to reduce stresses, in particular by absorbing the drive movement and / or the drive torque or by transmitting the drive movement and / or the drive torque in the circumferential direction.

[0029] The tongues can be circumferentially rigid to absorb the drive torque or rotational movement. The rigidity can be adjusted by changing the circumferential extent of the tongues. The greater the extent, the stiffer the tongues.

[0030] Another factor influencing the circumferential stiffness of the tongues is their axial length. The shorter the axial length, the stiffer the tongues are in the circumferential direction, thus enabling a more uniform force distribution. The longer the axial length, the larger the surface area of ​​the tongues for force transmission. The length of the tongues can depend on the application, allowing for the axial length to be designed taking into account the expected circumferential forces and the material properties of the tongues or the coupling element, ensuring that the mechanical stresses acting on the tongues do not exceed a predetermined limit. Depending on the requirements, the axial length of a tongue can range from one-quarter to three-eighths of the total axial length of the coupling element.

[0031] The tongues can be radially deformable or soft. This allows the coupling element to deform according to the positional deviation. In this way, the positional deviation within the steering gear can be compensated for. In particular, the radial deformability can compensate for an axial misalignment of the transmission element. Radial deformability with sufficient tongue strength can be achieved, especially with wall thicknesses of 0.7–1 mm.

[0032] The tongues of the first and / or second fastening area can have a radial preload, so that when the coupling element is connected to the transmission element and / or to the drive interface, a preloaded and therefore backlash-free connection can be made.

[0033] The mounting area of ​​the transmission element and / or the mounting area of ​​the drive interface may have trench-like milled recesses, indentations, and / or depressions designed as corresponding mounting structures for engagement with the corresponding mounting structures of the coupling element. Alternatively or additionally, the mounting area of ​​the transmission element and / or the mounting area of ​​the drive interface may have corresponding raised sections designed for engagement with the corresponding mounting structures of the coupling element.

[0034] The design of the mounting structures allows for appropriate mobility between the transmission element, coupling element, and / or drive interface during operation. Specifically, the transmission element, coupling element, and / or drive interface can be designed to be axially displaceable, axially tiltable, radially movable, and / or radially tiltable relative to each other. This allows for deformation to compensate for positional deviations.

[0035] The first mounting area can be made of a different material than the second mounting area. This allows for the adjustment of desired deformation behavior in the radial direction and / or desired stiffness in the circumferential direction.

[0036] Additionally or alternatively, one of the first or second fastening areas, in particular the tongues of the corresponding fastening area, can be radially stiffer than the other. This allows the location of the deformation point of the coupling element to be influenced by the design. To influence or adjust the radial stiffness, the tongues can have stiffening elements, such as ribs or beads, which extend essentially axially, in particular along the direction of rotation, along the corresponding tongue.

[0037] Another way to influence the radial stiffness of the tongues is by selecting the material thickness. This can range from 0.7 mm to 1 mm, enabling a compact and nested arrangement of the coupling element between the transmission element and the drive interface.

[0038] The mounting structure of the first and / or second mounting area can have a surface almost perpendicular to the circumferential direction, in particular a vertical surface for force transmission, or a substantially radially extended surface for force transmission. The surface can, for example, have an angle of more than 70 degrees to the circumferential direction. The surface can, in particular, extend axially. These surfaces serve to ensure that the force transmission between the drive interface and the coupling element, or between the coupling element and the transmission element, is as free as possible from transverse or radial forces. The mounting area, in particular the mounting structure(s), of the transmission element can have a correspondingly designed surface for force transmission so that the force transmission can occur as free as possible from transverse or radial forces.Alternatively or additionally, the mounting area, in particular the mounting structure(s), can have a surface designed accordingly for force transmission at the drive interface, so that the force transmission can take place as free as possible from transverse or radial forces.

[0039] The surfaces for force transmission of the transmission element and / or the drive interface can be designed as an axially drawn profile, thus enabling axial movements under torque during assembly or operation. This also allows tilting in the event of axial misalignment, similar to a gimbal.

[0040] The fastening structure can be located at a distal end of the tongues or extend from this end along the tongue, either partially or completely, towards the center of the coupling element, particularly towards the closed section. The width of the fastening structure can be uniform along its entire length. This allows for the efficient creation of the fastening structure through forming.

[0041] The circumferential width of the tongues can range from 9 to 16 mm, preferably 14 mm. This ensures sufficient circumferential stiffness of the tongues. Alternatively, the width of the mounting structure can be reduced (e.g., gradually towards the mounting structure).

[0042] The tongues and the mounting structure attached to them can be continuous. This means that the surface of each tongue forms a continuous surface with the surface of the mounting structure attached to it. This continuous surface results in high strength for both the tongues and the mounting structures. According to one embodiment, the mounting structures have no holes and / or recesses that could reduce their rigidity.

[0043] According to one embodiment, the at least one fastening structure can have at least one recess and / or at least one projection, wherein the transmission element and the drive interface have at least one corresponding fastening structure for connection with the at least one fastening structure of the coupling element. The recess and / or projection can be designed as a single closed structure (i.e., there must be no holes or openings such as in a tab). This increases the strength. The torque capacity can be achieved by the coupling element by preventing the tongues from twisting or bolting. The recess and / or projection can have a radial height relative to the motion transducer and / or the transmission element. The radial height of the respective fastening structure can be in the range of 2–6 mm.The fastening structure and / or a surface of the fastening structure for force transmission can run essentially perpendicular (>70°) to the circumferential direction of the coupling element. This allows contact forces to be transmitted inwards / outwards with virtually no transverse or radial forces.

[0044] Axially drawn tongue fastening structures can permit axial movement under torque, for example during assembly or operation. Furthermore, the surface geometry of the coupling element can also allow tilting and / or bending in case of axial misalignment. In this way, the coupling element can perform an axial drilling movement to compensate for further positional tolerances.

[0045] According to one embodiment, the coupling element can have holes or recesses to achieve a specific degree of flexibility in the coupling element at certain points.

[0046] According to one embodiment, the steering gear has a housing that is divided into a first housing section and a second housing section, with the drive interface being located in the first housing section and the transmission element in the second housing section. In addition to the drive interface, other elements, such as the drive unit, may be located in the first housing section. In addition to the transmission element, other elements, such as the intermediate element of the motion converter or the motion converter as a whole, may be located in the second housing section. In particular, it may be provided that the drive interface and other elements connected to the drive interface that are not connected to the drive interface via the coupling element, such as the drive unit, are located exclusively in the first housing section. In this way, the first housing section forms a first block.Furthermore, it can be provided that the transmission element and other elements connected to the transmission element, which are not connected to the transmission element via the coupling element, such as the intermediate element of the motion converter or the motion converter as a whole, are mounted exclusively in the second housing section. In this way, the second housing section forms a second block. The housing sections or blocks can be connected to each other by fastening elements. Both blocks, more precisely the drive interface and the transmission element, are connected to each other via the coupling element, whereby possible positional deviations of the transmission element or housing tolerances are compensated for by a corresponding deformation of the coupling element. In this way, it can be ensured that the axis of rotation of the drive interface and, if applicable, other axes of rotation, such as...The drive unit is not affected by positional deviations of the transmission element or housing tolerances. Therefore, the two blocks are decoupled.

[0047] The drive interface, the output interface, the motion converter, and the coupling element can be at least partially enclosed by the housing. The motion converter can be rotatably mounted to the housing. The output interface can be rotatably mounted to the housing on at least one side and preferably to the drive unit on the opposite side. The output interface can have limited freedom of movement (axial and tilting).

[0048] According to one embodiment, the coupling element can be made of or comprise a metallic material. Metal, for example, can withstand higher surface pressures than plastics, allowing a drive torque or rotary motion to be transmitted from the drive interface to the coupling element, or from the coupling element to the transmission element, over a comparatively small area. The coupling element can be manufactured from a metal sheet blank or consist entirely of a metal sheet. This allows for the use of common sheet metal fabrication processes for manufacturing the coupling element. For example, one manufacturing step can involve deep drawing the sheet material to form the closed section of the coupling element. The tongues described above can alternatively or additionally be manufactured by stamping.The fastening structures on the tongues and / or stiffening elements on the tongues can be manufactured using a forming technique, e.g., by deep drawing or embossing.

[0049] The closed section of the coupling element can have a diameter in the range of 40-50 mm to form a stable structure.

[0050] Another aspect of the invention relates to an element for transmitting a rotary motion in a steering gear as described above. The element can be configured as the transmission element or as the drive interface. In particular, the element is provided with corresponding fastening structures that enable coupling with the coupling element of the steering gear via corresponding fastening structures on the tongues of the coupling element. In particular, the element can be configured for a nested arrangement with the coupling element.

[0051] Another aspect of the invention relates to a coupling element for a steering gear as described above. The coupling element can, in particular, be made of a metallic material or have a metallic composition.

[0052] Another aspect of the invention relates to a method for manufacturing a coupling element as described above. Method steps or embodiments of the method that are not explicitly mentioned below, but which are readily apparent to a person skilled in the art from the preceding description, are to be regarded, at the very least, as further developments of the method disclosed herein. Likewise, manufacturing steps described below are always to be understood, in their result, as further developments of the items described above.

[0053] The process may include, in particular, a forming step in which a blank is produced and / or in which the finished coupling element is manufactured. Forming is a well-known and easily controlled technique, especially in sheet metal processing.

[0054] The method may, in particular, include forming the coupling element from a tubular blank or from a sheet metal by deep drawing. The method may further include creating radial cutouts on the tongue to form the fastening structures. The method may also include forming arcs adjacent to the recesses or projections of the fastening structures. After forming, heat treatment / hardening may preferably be carried out to increase the mechanical strength and to relieve stresses, which are typically in the range of 300–700 MPa. Possible further process steps include the creation of corrosion / wear protection, especially by coating, particularly in the case of metal-to-metal connections. Alternatively or additionally, corrosion / wear protection may be achieved by mechanical surface treatment such as descaling, brushing, or blasting.

[0055] The method can also include providing intermediate elements such as plastic discs / rings in the area of ​​the fastening areas, particularly in the area of ​​the tongues. Detailed description based on drawing

[0056] Further measures improving the invention are described in more detail below, together with a description of a preferred embodiment of the invention, with reference to the figures. The figures show: Fig. 1 a schematic perspective sectional view of a steering gear according to an embodiment of the invention, Fig. 2 the steering gear Fig. 1 in a cutaway side view, Fig. 3 a perspective view of part of the steering gear Fig. 1, Fig. 4 a combination of transmission element and coupling element of the steering gear made of Fig. 1, Fig. 5 a combination of drive interface and coupling element of the steering gear Fig. 1, Fig. 6 the transmission element of the steering gear Fig. 1, Fig. 7 the drive interface of the steering gear Fig. 1, Fig. 8 and Fig. 9 perspective views of the coupling element of the steering gear from Fig. 1, Fig. 10 a detailed view of the steering gear Fig. 1, Fig. 11 a detailed view of the steering gear Fig. 1, Fig. 12 the coupling element of the steering gear Fig. 1, and Fig. 13 and Fig. 14 perspective views of the coupling element according to a second embodiment.

[0057] The figures are purely schematic and serve only to illustrate the invention. The same elements are identified by the same reference symbols. All drawings depict the objects shown in their respective initial positions.

[0058] The Fig. 1, Fig. 2, Fig. 3, Fig. 4, Fig. 5, Fig. 6, Fig. 7, Fig. 8, Fig. 9, Fig. 10, Fig. 11 to Fig. Figure 12 schematically and exemplarily shows different elements and views of a steering gear according to one embodiment of the invention. The following description therefore refers to all of the Fig. 1, Fig. 2, Fig. 3, Fig. 4, Fig. 5, Fig. 6, Fig. 7, Fig. 8, Fig. 9, Fig. 10, Fig. 11 to Fig. 12.

[0059] Shown is a steering gear 1 for a vehicle. The steering gear 1 comprises - a drive interface 2 configured to be driven by a drive unit 3, wherein the drive interface 2 is rotatable about a rotary axis 4, - an output interface 5, which is designed to execute a steering movement, - a motion converter 6 configured to convert the rotary motion of the drive interface 2 into the steering motion, wherein the motion converter has a transmission element 6.1 configured to receive the rotary motion of the drive interface 2, and - a coupling element 7, which is provided between the drive interface 2 and the motion converter 6, and couples the drive interface 2 to the motion converter 6 in such a way that the rotary motion of the drive interface 2 can be transmitted to the motion converter 6, wherein the coupling element 7 is designed to be deformed in the event of a positional deviation X of the transmission element 6.1 from an initial position.

[0060] The drive interface 2 is designed as an externally toothed gear, rotatable about the axis of rotation 4. The drive interface 2 is connected to a drive unit 3, which can drive the drive interface 2. For this purpose, the drive unit 3 has a motor 3.1, in this case a rotary electric motor, and a pinion 3.2 rotatable about a drive axis of rotation 3.3, which engages with the teeth 2.2 of the drive interface 2.

[0061] The rotation of the drive interface 2 is converted into a steering movement by the steering gear 1, more precisely via the motion converter 6, which can then be transmitted via the output interface 5. The steering movement is a rectilinear movement, e.g., a translational and / or linear movement. The output interface 5 is designed as a moment-free mounting for a tie rod, the displacement of which by the output interface 5 ultimately steers a wheel connected to the tie rod (not shown). The connection between output interface 5 and tie rod can, as shown here, include a ball joint and a corresponding ball joint mount to achieve the moment-free mounting of the tie rod.

[0062] The motion converter 6 is designed here as a ball screw drive, which includes, as an intermediate element 6.2, a spindle arranged coaxially to the axis of rotation 4 in its initial position and designed to be displaceable along the axis of rotation 4. The intermediate element 6.2 extends through the transmission element 6.1 of the motion converter 6. The ends of the spindle are designed as the output interface 5, as is the case, for example, in Fig. 1 is recognizable.

[0063] The intermediate element 6.2 extends through a transmission element 6.1 of the motion converter 6, which is designed here as a ball screw nut and is coaxial to the axis of rotation 4 in its initial position and rotatable about it. A rotation of the transmission element 6.1 thus causes a displacement of the intermediate element 6.2 along the axis of rotation 4.

[0064] As in Fig. As can be seen in Figure 2, the transmission element 6.1 extends through the drive interface 2 in the direction of the axis of rotation 4. The transmission element 6.1 and the drive interface 2 are rotationally fixed to each other, so that the rotational movement of the drive interface 2 can be transmitted to the transmission element 6.1. In other words, the transmission element 6.1 can be set in rotation by rotating the drive interface 2 and ultimately by the drive unit 3, so that ultimately a steering movement can be transmitted as a translational movement from the intermediate element 6.2 via the output interface 5 to a tie rod for steering the wheels by means of a rotational movement of the drive unit 3.

[0065] For the rotationally fixed coupling of transmission element 6.1 and drive interface 2, as described in Fig. 2. To identify, a coupling element 7 is provided between transmission element 6.1 and drive interface 2.

[0066] The coupling element 7 serves on the one hand to transmit the rotary motion of the drive interface 2 to the transmission element 6.1, on the other hand it is designed to be deformable, so that positional deviations X of elements within the steering gear 1, in this case within the motion converter 6, can be compensated.

[0067] Such positional deviations X can have various causes. On the one hand, the conversion of the rotary motion of the drive interface 2 or the transmission element 6.1 into a translational motion of the intermediate element 6.2, and the resulting high forces acting within the motion converter 6, can cause a positional deviation X of the transmission element 6.1. In other words, the transmission element 6.1 can become misaligned. It is then no longer coaxial with the axis of rotation 4.

[0068] Another cause for a positional deviation X could be manufacturing tolerances of the steering gear 1, in particular of a housing 10 of the steering gear 1. As in the Fig. 1 and Fig. As can be seen in Figure 2, the steering gear has a housing 10 comprising a first housing section 10.1 and a second housing section 10.2. Both housing sections 10.1 and 10.2 are connected to each other by means of fastening elements 10.3, such as screws, so that the motion converter 6 and the drive interface 2 are located inside the housing 10. The bearing 8, which rotatably supports the drive interface 2, and the bearing 9, which rotatably supports the transmission element 6.1, are located in the housing 10. Due to manufacturing tolerances of the housing 10 or the housing sections 10.1 and 10.2, a positional deviation X of the transmission element 6.1 may occur, either alternatively or additionally, when both housing sections 10.1 and 10.2 are connected.

[0069] The positional deviation X, which as described above can have different causes, is exemplary and exaggerated in the following. Fig. 2 is marked.

[0070] As in Fig. 1 and Fig. As can be seen in Figure 2, the drive interface 2 is an externally toothed gear engaged with the pinion 3.2 of the drive unit 3. A positional deviation X of the transmission element 6.1 could, if it affects the drive interface 2, cause a deviation in the tooth engagement, which can result in an altered contact pattern in the tooth engagement, potentially leading to damage or even undesirable acoustic behavior.

[0071] The coupling element 7, located between the transmission element 6.1 and the drive interface 2, is designed to be deformable. This deformability is such that the coupling element 7 is rigid in the direction of the transmission of the rotary motion and deformable in the direction of the positional deviation X. In other words, the coupling element 7 is rigid in the circumferential direction, i.e., about the axis of rotation 4, while it is deformable, at least in sections, in the radial direction with respect to the axis of rotation 4. In this way, the rotary motion or a torque can be transmitted from the drive interface 2 to the coupling element 7 and further to the transmission element 6.1, while in the event of a positional deviation X of the transmission element 6.1, this deviation X is compensated for by corresponding deformation of the coupling element 7, thus preventing the positional deviation from being transmitted further to the drive interface 2.

[0072] To implement this functionality, a coupling element 7 is provided, which is located particularly in the Fig. 8, Fig. shown in 9 and 12.

[0073] The coupling element 7 is made of a metallic material. This facilitates its manufacture using known sheet metal working methods.

[0074] The coupling element 7 is shown in relation to the axis of rotation 4. It has a central section, which is designed as a closed section 7.1. This section is designed here in a sleeve-like form and is closed in the circumferential direction around the axis of rotation 4. This makes the coupling element 7 rigid in the circumferential direction around the axis of rotation 4, so that the rotary motion of the drive interface 2 or the torque of the drive interface 2 can be transmitted to the coupling element 7 and further to the transmission element 6.1 as directly and / or without loss as possible.

[0075] Along the axis of rotation 4, the coupling element 7 has a first fastening area 7.2 and a second fastening area 7.3. Both fastening areas 7.2, 7.3 are located along the axis of rotation 4 at opposite ends of the closed section 7.1.

[0076] The first fastening area 7.2 has three tongues 7.2.1 spaced 120 degrees apart about the axis of rotation 4, thus maintaining a regular spacing. The tongues 7.2.1 extend substantially away from the closed section 7.1 and along the axis of rotation 4. Each tongue 7.2.1 is provided with a fastening structure 7.2.2 designed to engage with the transmission element 6.1. The transmission element 6.1 has corresponding fastening structures 6.1.1 spaced at regular intervals around its circumference. The fastening structures 7.2.2 on the tongues 7.2.1 are radially inward-facing. That is, the fastening structures 7.2.2 extend radially inward from the surface of the tongues 7.2.1 as recesses.This results in a structure that has four surfaces circumferentially around the axis of rotation, oriented either perpendicular to the surface of the corresponding tongue 7.2.1 or radially oriented. The fastening structures 7.2.2 thus represent radially inwardly directed projections that engage with the fastening structures 6.1.1 of the transmission element 6.1, which are designed here as recesses. The transmission of the rotational movement from the coupling element 7 to the transmission element 6.1 occurs via the engagement of the fastening structures 7.2.2 of the tongues 7.2.1 with the fastening structures 6.1.1 of the transmission element 6.1. The surfaces that are oriented perpendicular to the surface of the corresponding tongue 7.2.1 or radially oriented transmit the rotational movement and / or the torque to the transmission element 6.1 by contacting corresponding surfaces of the fastening structures 6.1.1 of the transmission element 6.1.

[0077] The second mounting area 7.3 has three tongues 7.3.1 spaced 120 degrees apart about the axis of rotation 4, thus maintaining a regular spacing. The tongues 7.3.1 extend essentially away from the closed section 7.1 and along the axis of rotation 4. Each tongue 7.3.1 is provided with a mounting structure 7.3.2, designed to engage with the drive interface 2. For this purpose, the drive interface 2 has corresponding mounting structures 2.1, spaced apart from each other on an inner surface of the drive interface 2. The mounting structures 7.3.2 on the tongues 7.3.1 are radially outward oriented. That is, the mounting structures 7.3.2 extend radially outward from the surface of the tongues 7.3.1 as raised projections.This results in a structure that has four surfaces circumferentially around the axis of rotation, oriented either perpendicular to the surface of the corresponding tongue 7.3.1 or radially oriented. The fastening structures 7.3.2 thus represent radially outward-facing projections that engage with the fastening structures 2.1 of the drive interface 2, which are designed here as recesses. The transmission of the rotary motion from the drive interface 2 to the coupling element 7 occurs via the engagement of the fastening structures 7.3.2 of the tongues 7.3.1 with the fastening structures 2.1 of the drive interface 2. The rotary motion and / or the torque of the drive interface 2 are transmitted to the surfaces that are oriented perpendicular to the surface of the corresponding tongue 7.3.1 or radially oriented by contacting corresponding surfaces of the fastening structures 2.1 of the drive interface 2.

[0078] Because the tongues 7.2.1, 7.3.1 extend essentially along the axis of rotation 4, they are designed to be as stiff as possible so that the rotational movement or torque can be transmitted accordingly.

[0079] Simultaneously, tongues 7.2.1 and 7.3.1 are thin in the radial direction, making them deformable. This means that tongues 7.2.1 and 7.3.1 can be bent or deformed radially. In this way, the coupling element 7 can be deformed accordingly in the case of the positional deviation X described above, without breaking the coupling between drive interface 2 and transmission element 6.1.

[0080] As in the Fig. 8 and Fig. As can be seen in Figure 9, the tongues 7.2.1 of the first fastening area 7.2 have a region between the respective fastening element 7.2.2 and the closed section 7.1 that extends only axially and essentially has no radially extending structures. In contrast, the fastening elements 7.3.2 of the tongues 7.3.1 of the second fastening area 7.3 extend from the axially free end of the respective tongue 7.3.1 to the closed section 7.1. This means that the fastening elements 7.3.2 of the tongues 7.3.1 have a radially stiffening effect on them. In the embodiment shown here, the tongues 7.3.1 of the second fastening area 7.3 are therefore radially stiffer than the tongues 7.2.1 of the first fastening area 7.2. A deformation of the coupling element 7 as a result of the positional deviation X will therefore primarily occur at the softer tongues, namely the tongues 7.2.1 of the first fastening area 7.2.

[0081] In general, the radial stiffness or flexibility of the tongues 7.2.1, 7.3.1 can be adjusted by constructive design, which ultimately influences where the deformation in the coupling element 7 and thus the compensation of the positional deviation X occurs.

[0082] The coupling element 7 is designed here as a sheet metal part. The steering gear 1 is designed such that the deformation of the coupling element 7 is elastic in order to prevent material fatigue.

[0083] The coupling element 7 can be manufactured by forming, e.g., from a tube blank or by deep drawing from a sheet. The tongues 7.2.1, 7.3.1 can be manufactured by stamping. The fastening structures 7.2.2, 7.3.2 can be manufactured by a forming technique, e.g., deep drawing or embossing. The coupling element 7 may, particularly after forming, have been treated by heat treatment and / or a hardening process to increase its mechanical strength. In this way, a coupling element 7 can be manufactured using simple metalworking processes.

[0084] Furthermore, by manufacturing the coupling element 7 as a sheet metal part, a nested arrangement of the drive interface 2, the transmission element 6.1, and the coupling element 7 located between them is possible in a space-saving manner. Typical sheet thicknesses for the coupling element 7 can range between 0.7 mm and 1 mm.

[0085] In the Fig. 3, Fig. 4, Fig. 5, Fig. 6 to Fig. Figure 7 shows different assembly states of coupling element 7, drive interface 2 and transmission element 6.1, so that the nested arrangement becomes clear.

[0086] Fig. Figure 12 shows a cross-sectional view of the coupling element 7, with the axis of rotation 4 extending from left to right. Several dimensions are indicated that serve to define the coupling element 7. Srad1 and Srad2 represent the radial heights of the fastening structures 7.2.2 and 7.3.2. A minimum height of 2 mm is advantageous to ensure good transmission of the rotational movement and / or torque. A maximum height of 6 mm is advantageous to avoid excessive deformation of the sheet metal. Furthermore, the maximum height also prevents excessive twisting of the fastening structures 7.2.2 and 7.3.2 when forces are transmitted in the circumferential direction.

[0087] Sax1 represents the extent of the closed section 7.1 along the axis of rotation 4. In other words, Sax1 corresponds to the width of the closed section 7.1. Sax2 and Sax3 represent the respective extents of the tongues 7.2 and 7.3 along the axis of rotation 4. To achieve the stiffest possible design of the coupling element 7 in the circumferential direction, the widest possible closed section can be chosen. Typically, the width, i.e., Sax1, is between half and one-quarter of the sum of the lengths Sax1, Sax2, and Sax3.

[0088] The diameter of the closed section 7.1 can be 40-50 mm. This makes it possible to arrange the coupling element 7 accordingly around the transmission element 6.1.

[0089] In Fig. 2 as well as in Fig. Figure 10 shows that the bearing 9, with which the transmission element 6.1 is mounted in the housing 10, more precisely in the second housing section 10.2, is formed integrally with the transmission element 6.1.

[0090] Alternatively or additionally, it can be seen that the bearing 9 is resiliently arranged in the second housing section 10.2. It therefore has a limited degree of freedom in the axial direction and with respect to tilting. The drive interface 2 and its bearing 8 are arranged in the first housing section 10.1. Both housing sections 10.1 and 10.2 are connected to each other in an assembly step by fastening elements 10.3, as described above, thereby establishing a positive engagement of the fastening elements 7.2.2 with the fastening elements 6.1.1 of the transmission element 6.1 and a positive engagement of the fastening elements 7.3.2 with the fastening elements 2.1 of the drive interface 2. The support of the drive interface 2 via the bearing 8, which is located in the first housing section 10.1, and the support of the transmission element 6.1 via the bearing 9, which is located in the second housing section 10.2, result in a subdivision or...Decoupling of steering gear 1 takes place.

[0091] For drive unit 3, a fixed position of the axis of rotation 3.3 is essential because there is only a small gap between the stator and rotor of drive unit 3, and any misalignment of the axis of rotation 3.3 could cause the rotor and stator to contact. For gears, such as the pinion 3.2 and the drive interface 2 that engages with it, a fixed position of the axis of rotation 3.3 or the axis of rotation 3 is equally essential to ensure that the meshing gears 2 and 3.2 have a fixed center distance, resulting in a smooth contact pattern. This prevents damage and / or noise disturbances. Similarly, a belt drive must be operated with a fixed position of the corresponding axis and / or a fixed center distance to prevent the belt from skipping, breaking, overheating, or running noisily.

[0092] Ensuring that the position of the axis of rotation 3.3 of the drive unit 3, or the position of the axis of rotation 4 of the drive interface 2, is not affected by the positional deviation X of the transmission element 6.1 is achieved here by the positioning of the bearings 8 and 9. The bearing 8, which supports the drive interface 2, is located in the first housing section 10.1, while the bearing 9, which supports the transmission element 6.1, is located in the second housing section 10.2. Thus, at least the drive unit 3, together with the drive interface 2, the bearing 8, and the first housing section 10.1, form a first block. A second block is formed, at least, by the motion converter 6, the bearing 9, and the second housing section 10.2. Both blocks are connected by the fastening elements 10.1 and 10.2 of the housing sections 10.1 and 10.2.3 are attached to each other, with the only other coupling besides this connection being the coupling by the coupling element 7. This means that any possible positional deviation X of the transmission element 6.1 is compensated for by the coupling element 7, more precisely: by its deformation, between the two blocks, without the position of the axis of rotation 3.3 of the drive unit 3 or the position of the axis of rotation 4 of the drive interface 2 being affected by the positional deviation X.

[0093] The Fig. 13 and Fig. Figure 14 shows perspective views of the coupling element according to a second embodiment.

[0094] In contrast to the previously shown embodiment, a wider closed section 7.1 is provided here. This means that the axial extent of the closed section 7.1 is greater than in the embodiment shown above. Fig. 1, Fig. 2, Fig. 3, Fig. 4, Fig. 5, Fig. 6, Fig. 7, Fig. 8, Fig. 9, Fig. 10, Fig. 11 to Fig. 12. In this case, tongues 7.2.1 and 7.3.1 are shorter, assuming an identical overall axial extension of the coupling element 7. Reference symbol list 1 Steering gear 2 Drive interface 2.1 Mounting structure 2.2 Gearing 3 Drive unit 3.1 Engine 3.2 Sprocket 3.3 Drive axis 4 axis of rotation 5 Output interface 6 motion converters 6.1 Transmission element 6.1.1 Mounting structure 6.2 Intermediate element 7 Coupling element 7.1 Closed section 7.2 First fastening area 7.2.1 Tongue 7.2.2 Mounting structure 7.3 Second fastening area 7.3.1 Tongue 7.3.2 Mounting structure 8 bearings 9 warehouses 10 cases 10.1 First housing section 10.2 second housing section 10.3 Fastening element X Positional deviation

Claims

Steering gear (1) for a vehicle, comprising: - a drive interface (2) configured to be driven by a drive unit (3), wherein the drive interface (2) is rotatable about a rotary axis (4), - an output interface (5) configured to perform a steering movement, - a motion converter (6) configured to convert the rotary movement of the drive interface (2) into the steering movement, wherein the motion converter includes a transmission element (6.1) has a drive interface (2) designed to receive the rotary motion of the drive interface, and a coupling element (7) provided between the drive interface (2) and the motion converter (6), coupling the drive interface (2) to the motion converter (6) in such a way that the rotary motion of the drive interface (2) can be transmitted to the motion converter (6), wherein the coupling element (7) is designed to be deformed in the event of a positional deviation (X) of the transmission element (6.1) from an initial position. Steering gear (1) according to claim 1, further comprising a drive unit (3) which is in contact with the drive interface (2) and is configured to drive the drive interface (2). Steering gear (1) according to one of the preceding claims, wherein the coupling element (7) comprises a section (7.1) closed in the circumferential direction with respect to the axis of rotation (4) and arranged coaxially to the axis of rotation (4). Steering gear (1) according to one of the preceding claims, wherein the coupling element (7) has a first mounting area (7.2) which is rotationally fixed to the motion converter (6) and wherein the coupling element (7) has a second mounting area (7.3) which is rotationally fixed to the drive interface (2). Steering gear (1) according to one of the preceding claims, wherein the first mounting area (7.2) and / or the second mounting area (7.3) each comprise at least three tongues (7.2.1, 7.3.1) extending from the coupling element (7) in a longitudinal axis of the coupling element (7) and / or along the axis of rotation (4), wherein the tongues (7.2.1, 7.3.1) each have at least one mounting structure (7.2.2, 7.3.2). Steering gear (1) according to one of the preceding claims, wherein the steering gear (1) has a housing (10) which is divided into a first housing section (10.1) and a second housing section (10.2), wherein the drive interface (2) is mounted in the first housing section (10.1) and the transmission element (6.1) is mounted in the second housing section (10.2). Steering gear (1) according to one of the preceding claims, wherein the coupling element (7) is made of or comprises a metallic material. Element for transmitting a rotary motion in a steering gear (1) according to one of claims 1 to 7, wherein the element is designed as a transmission element (6.1) or as a drive interface (2). Coupling element (7) for a steering gear (1) according to one of claims 1 to 7 . Method for manufacturing a coupling element (7) according to claim 9.

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