A steering system and a method for manufacturing multiple steering systems.

Abstract

To provide a method for manufacturing multiple steering systems. [Solution] The steering system components include at least an electric motor, a steering gear device including a first steering gear input shaft connectable to a steering shaft, a second steering gear input shaft driven by the electric motor, and a steering gear output shaft, and a steering gear device housing, which comprises a plurality of fixing elements for fixing the steering gear device housing to a higher structure, particularly the vehicle body. The steering system is characterized in that the steering gear device housing is configured such that a steering system can be manufactured that is mirror-symmetric with respect to the steering system with respect to at least the arrangement and orientation of the first and second steering gear input shafts, the steering gear output shaft, and the fixing elements, particularly with respect to a vertical mirror surface.

Description

TECHNICAL FIELD

[0001] The present invention relates to a steering system composed of steering system components, wherein the steering system components include at least an electric motor, a first steering gear input shaft that can be connected to a steering shaft, a second steering gear input shaft that is drivingly connected to the electric motor, and a steering gear output shaft, and a steering gear device housing that is provided with a plurality of fixing elements for fixing the steering gear device housing to a higher-level structure, in particular to a vehicle body.

[0002] The present invention relates to a method for manufacturing a plurality of steering systems.

BACKGROUND ART

[0003] A power steering system is known from German Utility Model No. 202014101670U1 specification. The power steering system includes a steering wheel shaft, and a first worm screw and a worm wheel are coaxially arranged on the steering wheel shaft. The power steering system further includes an auxiliary power shaft, and a second worm screw meshing with the worm wheel is coaxially arranged on the auxiliary power shaft. The power steering system further includes a segment shaft having a gear segment that meshes with the first worm screw.

[0004] A steering gear for an electromechanical steering system for a vehicle is known from German Patent Application Publication No. 102019127965A1 specification. The steering gear comprises an input shaft that can be connected to or is connected to the steering column of the steering system, a segment shaft that can be connected to or is connected to the pitman arm of the steering system, an angle gear, a servo gear, and an electric motor for driving the servo gear. The angle gear is designed as a bevel gear mechanism. The input shaft and electric motor are connected to a servo gear. The servo gear is connected to the angle gear. The angle gear is connected to a segment shaft. The angle gear is configured to transmit torque from the servo gear to the segment shaft via two transmission paths.

[0005] German Patent Application No. 10234596B3 describes a non-trajectory-constrained power steering system for automobiles, configured as a ball-recirculating steering system. To enhance the variability of the ball-circulating steering system, a servo motor, configured as an electric motor, is positioned at the steering gear input to reduce the manual force required for steering.

[0006] From German Patent Application Publication No. 102015217045A1, a commercial vehicle steering system including a steering gear for transmitting manual torque applied to the steering wheel to a pitman arm is known. The steering gear is equipped with an electric motor to supply auxiliary torque for steering assistance, and steering assistance is provided entirely electrically over the entire range of steering motion. The steering gear further comprises an input shaft and an output shaft, whose axes of rotation are in a torsional position relative to each other. The steering gear further comprises a first gear unit connecting the input shaft to the output shaft and a second gear unit to which an electric motor is connected on the input side. The second gear unit is connected to the output shaft on the output side, and the gear stages of the reduction gear unit are arranged coaxially with the output shaft. [Prior art documents] [Patent Documents]

[0007] [Patent Document 1] German Utility Model Specification No. 202014101670U1 [Patent Document 2] German Patent Application Publication No. 102019127965A1 Specification [Patent Document 3] German Patent Application No. 10234596B3 Specification [Patent Document 4] German Patent Application Publication No. 102015217045A1 Specification [Overview of the Initiative] [Problems that the invention aims to solve]

[0008] The object of the present invention is to provide the above-described steering system that can more easily configure both a steering system for right-hand drive vehicles and a steering system for left-hand drive vehicles. [Means for solving the problem]

[0009] This objective is achieved by a steering system characterized in that the steering gear device housing is configured such that it is possible to manufacture a steering system that is mirror-symmetric with respect to a vertical mirror surface, with respect to the arrangement and orientation of at least the first and second steering gear input shafts, the steering gear output shaft, and the fixed elements.

[0010] The steering system according to the present invention offers the possibility of easily realizing a mirror-symmetric steering system using identical parts, which facilitates adaptation to various vehicle types, particularly for left-hand drive and right-hand drive vehicles, without requiring complex new configurations. This enables efficient production and reduces both development and manufacturing costs.

[0011] The fixing elements of the steering gear device housing can be configured, for example, as through holes or screw holes for fixing screws.

[0012] In a special design, the torque path from the first steering gear input shaft to the steering gear output shaft comprises at least two gear stages connected in series in terms of drive technology. In particular, at least one of the gear stages can advantageously be configured as a wave gear mechanism, or as a cycloidal gear mechanism, or as an RV mechanism, or as a bevel gear mechanism. Advantageously, it is also possible for at least one of the gear stages to be configured as a worm gear mechanism, or as a spindle gear mechanism, or as a helical gear mechanism.

[0013] A helical gear mechanism can be understood as a gear comprising two helical gears that mesh directly with each other, whose rotational axes are in mutually skewed positions. In particular, the rotational axis of one of the gears can lie in one plane, and the rotational axis of the other gear is parallel to the surface normal of that plane. Advantageously, it can be contemplated that L<Dπsinβ holds for both helical gears. Here, L is the axial length of the gear, D is the root circle diameter of the oblique tooth trace, π is the circular constant, and β is the helix angle.

[0014] The RV mechanism means a gear system including a cycloidal gear mechanism and an upstream stage. The cycloidal gear mechanism includes at least one cycloidal disc having cycloidal external teeth, and the cycloidal external teeth mesh with roller pins arranged along the circumference. The movement of the cycloidal disc is generated by a plurality of eccentric shafts, each of which is arranged with an offset center and is rotatably supported to rotate on its own axis. Each eccentric shaft carries a gear with external teeth, and the gear meshes with a centrally arranged drive gear. The gear of the eccentric shaft and the drive gear are components of the upstream stage. That is, the drive gear transmits rotational motion to the gear of the eccentric shaft, whereby the eccentric shaft drives the cycloidal disc to perform oscillating motion, during which the cycloidal disc rolls in the circumferential direction along the circumference of the roller pins.

[0015] In a particularly advantageous embodiment, all steering system components are configured such that a steering system mirror-symmetric with respect to a steering system and a steering system with respect to a vertical mirror surface, with respect to the arrangement and orientation of at least the first and second steering gear input shafts, steering gear output shafts, and fixed elements. A particular advantage of this embodiment is the ability to use identical parts. All steering system components are configured to be used mirror-symmetrically, eliminating the need for different components for left-hand drive and right-hand drive vehicles. This reduces the number of variations, resulting in significant reductions in both production and logistics costs. Furthermore, the use of identical parts allows for economies of scale in manufacturing, further reducing production costs. Assembly is also simplified, as the same assembly groups can be used regardless of the installation direction. At the same time, serviceability is improved as there is no need to store various components for spare parts supply.

[0016] Alternatively, in embodiments including a worm, spindle, and helical gear as components of a gear stage configured, for example, as a worm gear mechanism, spindle gear mechanism, or helical gear mechanism, when the worm, spindle, and helical gear are replaced, respectively, by the same worm, spindle, and helical gear having opposite helical directions, the steering system components can be configured to enable the manufacture of a steering system that is mirror-symmetric with respect to a vertical mirror plane, particularly with respect to the arrangement and orientation of at least the first and second steering gear input shafts, steering gear output shafts, and fixed elements. Such embodiments also have the advantage of using substantially identical parts.

[0017] Whether it is necessary to replace the worm, spindle, and helical gears with worm, spindle, and helical gears in the opposite helical direction depends on how the rest of the steering system and the connections of the steering system within other steering elements in right-hand drive and left-hand drive vehicles are constructed.

[0018] In particularly advantageous embodiments, the first gear stage of the gear sequence is configured as a bevel gear mechanism, a worm gear mechanism, a spindle gear mechanism, a helical gear mechanism, or a harmonic drive mechanism, and the second gear stage, which is technically downstream of the first gear stage, is configured as a cycloidal gear mechanism, an RV mechanism, or a harmonic drive mechanism. Combining different gear types in two consecutive stages provides several important advantages for the steering system. A key advantage is that the required gear ratio can be achieved with a very compact design. Such embodiments allow for space-saving integration into vehicles, which is a significant advantage, especially in commercial vehicles where installation space is limited. Furthermore, the mechanical coupling interface of the steering system can be optimally positioned and aligned, thereby enabling easy and space-saving assembly into the vehicle. Such embodiments facilitate integration into various vehicle platforms.

[0019] In an advantageous embodiment of the steering system, an electric motor is connected to a second steering gear input via a power transmission gear system. This allows the motor's rotational speed and torque to be adapted to the requirements of the steering system.

[0020] Embodiments in which the power transmission gear device is configured as a traction means transmission mechanism or comprises a traction means transmission mechanism are particularly advantageous. Traction means transmission mechanisms, such as toothed belt or chain transmission mechanisms, enable low-noise and low-vibration power transmission. Furthermore, the traction means transmission mechanism allows the positioning of the electric motor relative to the steering gear device, which is particularly advantageous for utilizing the available installation space in the vehicle.

[0021] Alternatively, the power transmission gear device can be configured as a spur gear mechanism or comprise a spur gear mechanism. In order to achieve an advantageous transmission ratio with a compact design, the spur gear mechanism can advantageously comprise three spur gears.

[0022] In a further advantageous embodiment, it is contemplated that the power transmission gear device is designed as a wave gear mechanism or comprises a wave gear mechanism. The wave gear mechanism likewise enables a very compact design and, due to its backlash-free power transmission, provides particularly high steering accuracy.

[0023] In particular, the steering system can be configured such that, for example by means of the above-described special embodiment of the power transmission gear device, the motor is arranged axially offset relative to the second gear stage, in particular axially parallel, and / or axially parallel to the steering gear output shaft. This arrangement enables a space-saving design and allows flexible integration of the motor into the installation space of the vehicle.

[0024] Alternatively, the steering system can also be designed such that the motor is arranged coaxially with the second gear stage. This design ensures direct and low-loss power transmission, whereby the efficiency of the system is improved. Furthermore, a unit that is compact particularly in the radial direction is obtained, which enables easy assembly and maintenance.

[0025] The steering gear housing can advantageously be composed of multiple parts. A multi-part design for the steering gear housing allows for easy assembly. Furthermore, a multi-part design for the steering gear housing also facilitates maintenance, as it provides easy access to the enclosed steering system components.

[0026] Embodiments in which the steering gear device housing encloses the gear stages, at least in series with respect to the drive technology, are particularly advantageous. This protects the steering system components of the gear stages from external influences such as dust, moisture, or mechanical stress, and thus contributes to a longer lifespan and improved reliability of the steering system.

[0027] Furthermore, the steering gear housing can enclose the power transmission gear system, ensuring optimal protection against contamination and mechanical action.

[0028] In a particularly advantageous embodiment, the steering gear device housing includes at least one input shaft bearing housing for a steering gear input shaft bearing, particularly in an opening in the housing wall. A steering gear input shaft bearing can be positioned in the input shaft bearing housing for rotatable support of the steering gear input shaft. This enables stable support of the steering gear input shaft. The steering gear input shaft bearing can be advantageously configured as a rolling bearing, particularly as a ball bearing, as a roller bearing, or as an angular roller bearing.

[0029] An embodiment in which the steering gear device housing comprises an additional input shaft bearing housing in addition to the input shaft bearing housing, wherein the additional input shaft bearing housing is arranged mirror-symmetrically with respect to the horizontal mirror plane with respect to the first input shaft bearing housing, is particularly advantageous. A steering gear input shaft bearing for supporting the steering gear input shaft can be arranged in the input shaft bearing housing. This symmetrical design facilitates production and enables cost-effective implementation of left-hand drive and right-hand drive variants with respect to the rotational support of the steering gear input shaft.

[0030] Particularly advantageously, depending on whether the steering system is manufactured for a right-hand drive or left-hand drive vehicle, the steering gear input shaft bearing may be inserted into an input shaft bearing housing, or into a further input shaft bearing housing. Preferably, when the steering gear input shaft bearing is inserted into an input shaft bearing housing, the further input shaft bearing housing is closed off with a cover. Conversely, when the steering gear input shaft bearing is inserted into a further input shaft bearing housing, the input shaft bearing housing is preferably closed with a cover. The cover is preferably configured to be removable without damage, for example, for maintenance purposes.

[0031] Alternatively, and advantageously, to ensure reliable rotatable support for the steering gear input shaft, the steering gear input shaft bearing may be inserted into both the input shaft bearing housing and a further input shaft bearing housing. Depending on whether the steering system is manufactured for a right-hand drive or left-hand drive vehicle, the steering gear input shaft protrudes from the steering gear device housing through the opening of the input shaft bearing housing or the opening of the further input shaft bearing housing. In this case, the openings of the other input shaft bearing housings are preferably closed with covers.

[0032] The steering gear device housing can, advantageously, be equipped with an output shaft bearing housing for the steering gear output shaft bearing, thereby enabling precise rotational support of the steering gear output shaft. The steering gear output shaft bearing can be positioned within the output shaft bearing housing.

[0033] An embodiment in which the steering gear device housing comprises an additional output shaft bearing housing in addition to the output shaft bearing housing, wherein the additional output shaft bearing housing is arranged mirror-symmetrically with respect to the first output shaft bearing housing. A steering gear output shaft bearing for supporting the steering gear output shaft can be arranged in the output shaft bearing housing. This symmetrical design facilitates production and enables cost-effective implementation of left-hand drive and right-hand drive variants with respect to the rotational support of the steering gear output shaft.

[0034] Particularly advantageously, depending on whether the steering system is manufactured for a right-hand drive or left-hand drive vehicle, the steering gear output shaft bearing may be inserted into an output shaft bearing housing, or into a further output shaft bearing housing. Preferably, when the steering gear output shaft bearing is inserted into an output shaft bearing housing, the further output shaft bearing housing is closed off with a cover. Conversely, when the steering gear output shaft bearing is inserted into a further output shaft bearing housing, the output shaft bearing housing is preferably closed with a cover. The cover is preferably configured to be removable without damage, for example, for maintenance purposes.

[0035] Embodiments in which the distance from the plane perpendicular to the steering gear output shaft, where the rotation axis of the first steering gear input shaft is located, to the plane on which the outer portion of the steering gear device housing directly surrounding the output shaft bearing housing is located is particularly advantageous, especially if it is in the range of 70 mm to 90 mm, or particularly 80 mm. These dimensional settings achieve a good balance of compactness, structural stability, and efficient use of installation space.

[0036] The steering system can be advantageously designed so that the axes of rotation of the first steering gear input shaft and the steering gear output shaft are torsion relative to each other. This arrangement allows for particularly good use of installation space and integration into the vehicle. In particular, the axes of rotation of the first steering gear input shaft and the steering gear output shaft are further arranged in planes perpendicular to each other, which allows for particularly good use of installation space and integration into a vehicle. Embodiments in which the axes of rotation of the first steering gear input shaft and the steering gear output shaft are located at a distance of 80 mm to 100 mm, particularly 90 mm, are especially advantageous.

[0037] A steering system comprising a steering shaft operably connected to a steering control unit is particularly advantageous, wherein the steering shaft is preferably directly connected to or integrally manufactured with a first steering gear input shaft.

[0038] Furthermore, the steering system according to the present invention or a vehicle equipped with the steering according to the present invention, particularly commercial vehicles, especially trucks or buses, are particularly advantageous.

[0039] According to the present invention, a method for manufacturing multiple steering systems is provided, in which the steering system components are provided first, which is particularly advantageous. The steering system components include, in particular, a plurality of identical electric motors, a plurality of steering gear units, and a plurality of steering gear unit housings. Each steering gear unit includes a first steering gear input shaft connectable to a steering shaft, a second steering gear input shaft that is technically connected to or connectable to an electric motor, and a steering gear output shaft. Each steering gear unit housing includes a fixing element for fixing the steering gear unit housing to a higher structure, in particular the vehicle body, and the steering gear unit housings are configured to enable the manufacture of a steering system and a steering system that is mirror-symmetric with respect to a vertical mirror surface, with respect to the arrangement and orientation of at least the first and second steering gear input shafts, the steering gear output shaft, and the fixing elements. According to the present invention, the steering gear device housing is configured to enable the manufacture of both steering systems for right-hand drive vehicles and steering systems for left-hand drive vehicles.

[0040] Embodiments in which steering systems for left-hand drive and right-hand drive vehicles are assembled from completely identical steering system components are particularly advantageous. This leads to a significant reduction in the number of parts and, consequently, cost savings in production and logistics. Furthermore, the standardization of components simplifies warehouse management and reduces the complexity of assembly.

[0041] In a further advantageous embodiment, the steering systems for left-hand drive and right-hand drive vehicles may consist of the same components, except that a worm, spindle, or helical gear having a counter-helical orientation is used. [Effects of the Invention]

[0042] As already mentioned above, advantageously, depending on whether the steering system is manufactured for a right-hand drive or left-hand drive vehicle, the steering gear input shaft bearing may be inserted into an input shaft bearing housing or into a further input shaft bearing housing (arranged mirror-image to the input shaft bearing housing) with respect to the rotational support of the steering gear input shaft.

[0043] Similarly, as already mentioned above, advantageously, depending on whether the steering system is manufactured for a right-hand drive vehicle or a left-hand drive vehicle, the steering gear output shaft bearing may be inserted into an output shaft bearing housing or into a further output shaft bearing housing (arranged mirror-image to the output shaft bearing housing) with respect to the rotational support of the steering gear output shaft.

[0044] The scope of the present invention is schematically shown in the figures as an example, and will be described below with reference to the figures. Here, even in different exemplary embodiments, the same or identical elements are usually denoted by the same reference numerals. [Brief explanation of the drawing]

[0045] [Figure 1] This is a cross-sectional view of a first exemplary embodiment of the steering system according to the present invention. [Figure 2] This is a further cross-sectional view of a first exemplary embodiment of the steering system according to the present invention. [Figure 3] This is a side view of a first exemplary embodiment of the steering system according to the present invention. [Figure 4] This is a perspective view of a first exemplary embodiment of the steering system according to the present invention. [Figure 5] A perspective front view of a first exemplary embodiment of a steering system according to the present invention, and a further perspective front view of the steering system and a steering system that is mirror-symmetric with respect to a vertical mirror surface in particular. [Figure 6]A perspective rear view of a first exemplary embodiment of the steering system according to the present invention, and a further perspective rear view of the steering system and a steering system that is mirror-symmetric with respect to a vertical mirror surface in particular. [Figure 7] A side view of a first exemplary embodiment of a steering system according to the present invention, and a further side view of the steering system and a steering system that is mirror-symmetric with respect to a vertical mirror surface in particular. [Figure 8] This is a schematic detail diagram of the helical gear mechanism and RV mechanism of a first exemplary embodiment of the steering system according to the present invention. [Figure 9] This is a cross-sectional view of a second exemplary embodiment of the steering system according to the present invention. [Figure 10] This is a further cross-sectional view of a second exemplary embodiment of the steering system according to the present invention. [Figure 11] This is a side view of a second exemplary embodiment of the steering system according to the present invention. [Figure 12] This is a perspective view of a second exemplary embodiment of the steering system according to the present invention. [Figure 13] A perspective front view of a second exemplary embodiment of the steering system according to the present invention, and a further perspective front view of the steering system and a steering system that is mirror-symmetric with respect to a vertical mirror surface in particular. [Figure 14] A perspective rear view of a second exemplary embodiment of the steering system according to the present invention, and a further perspective rear view of the steering system and a steering system that is mirror-symmetric with respect to a vertical mirror surface in particular. [Figure 15] A side view of a second exemplary embodiment of the steering system according to the present invention, and a further side and rear view of the steering system and a steering system that are mirror-symmetric with respect to a vertical mirror surface in particular. [Figure 16] This is a schematic detail diagram of the helical gear mechanism and RV mechanism of a second exemplary embodiment of the steering system according to the present invention. [Figure 17]This is a schematic detail diagram of an exemplary embodiment of a combination of a helical gear mechanism and an RV mechanism for a steering system according to the present invention. [Figure 18] Figure 17 shows a schematic detail of a further exemplary embodiment of a combination of a helical gear mechanism and an RV mechanism for a steering system according to the present invention, which is mirror-symmetric to the steering system with respect to the arrangement and orientation of at least the first and second steering gear input shafts, steering gear output shafts, and fixed elements, as configured in the combination shown in Figure 17. [Figure 19] This is a cross-sectional view of a third exemplary embodiment of the steering system according to the present invention. [Figure 20] This is a further cross-sectional view of a third exemplary embodiment of the steering system according to the present invention. [Figure 21] This is a side view of a third exemplary embodiment of the steering system according to the present invention. [Figure 22] A perspective front view of a third exemplary embodiment of the steering system according to the present invention, and a further perspective front view of the steering system and a steering system that is mirror-symmetric with respect to a vertical mirror surface in particular. [Figure 23] A perspective rear view of a third exemplary embodiment of the steering system according to the present invention, and a further perspective rear view of the steering system and a steering system that is mirror-symmetric with respect to a vertical mirror surface in particular. [Figure 24] A side view of a third exemplary embodiment of the steering system according to the present invention, and a further side and rear view of the steering system and a steering system that are mirror-symmetric with respect to a vertical mirror surface in particular. [Modes for carrying out the invention]

[0046] Figure 1 shows a cross-sectional view of a first exemplary embodiment of the steering system 1 according to the present invention.

[0047] The steering system 1 consists of steering system components. The steering system components include an electric motor 2, a steering gear device 3 which includes a first steering gear input shaft 4 connectable to a steering shaft (not shown), a second steering gear input shaft 5 driven by the electric motor 2, and a steering gear output shaft 6. The steering system components also include a steering gear housing 7, which comprises a plurality of fixing elements 8 for fixing the steering gear housing 7 to a higher structure, particularly the vehicle body. The fixing elements 8 of the steering gear housing 7 can be configured, for example, as through holes or screw holes 9 for fixing screws.

[0048] The steering gear device housing 7 is configured to enable the manufacture of a steering system 11 that is mirror-symmetric to the steering system 1 with respect to the arrangement and orientation of at least the first steering gear input shaft 4 and the second steering gear input shaft 5, the steering gear output shaft 6, and the fixing element 8, particularly with respect to the vertical mirror surface 10, which is shown in Figures 5 to 7 and will be described in more detail below. Specifically, in this exemplary embodiment, the steering system components are configured such that a steering system 11 can be manufactured that is mirror-symmetric with respect to the steering system 1 with respect to the mirror surface 10, with respect to the arrangement and orientation of the first steering gear input shaft 4 and the second steering gear input shaft 5, the steering gear output shaft 6, and the fixed element 8, when the helical gears 17 and 18 of the helical gear mechanism 19 enclosed by the steering gear device housing 7 are replaced by identical helical gears having opposite helical directions.

[0049] Motor 2 is connected to the second steering gear input shaft 5 via a power transmission gear unit 12. The power transmission gear unit 12 is configured as a spur gear mechanism and includes a first spur gear 13, which is directly connected to the power output shaft 14 of the motor 2 in a manner that prevents relative rotation. The power transmission gear unit 12 further includes a rotatably supported second spur gear 15, the teeth of which mesh with the teeth of the first spur gear 13. The power transmission gear unit 12 further includes a third spur gear 16, which is directly connected to the second steering gear input shaft 5 in a manner that prevents relative rotation.

[0050] The torque path from the first steering gear input shaft 4 to the steering gear output shaft 6 comprises multiple gear stages connected in series in terms of drive technology. The first gear stage is configured as a helical gear mechanism 19, and the second gear stage, located downstream of the first gear stage in terms of drive technology, is configured as an RV mechanism 20.

[0051] The RV mechanism 20 comprises a cycloidal gear mechanism 21 and an upstream stage 22. The cycloidal gear mechanism 21 is technically connected downstream of the motor 2 via a power transmission gear unit 12 and an upstream stage 22. The cycloidal gear mechanism 21 includes two cycloidal discs 23 and 24, each having a cycloidal external gear row, which meshes with roller pins 25 arranged along the circumference. The movement of the cycloidal discs 23 and 24 is generated by a plurality of eccentric shafts 26, each centered off-center and supported by rolling bearings 27 to rotate relative to the cycloidal discs 23 and 24.

[0052] Each eccentric shaft 26 comprises an eccentric shaft gear 28 and a further eccentric shaft gear 29. The eccentric shaft gear 28 and the further eccentric shaft gear 29 of each eccentric shaft 26 are positioned on opposite sides of the two cycloidal discs 27.

[0053] The further eccentric shaft gear 29 is part of the upstream stage 22. The centrally located second steering gear input shaft 5 has an external gear row 30 that meshes with the external gear row of the further eccentric shaft gear 29. To that extent, the second steering gear input shaft 5 functions as the drive gear 57 of the upstream stage 22, transmitting its rotational motion to the further eccentric shaft gear 29. As a result, the eccentric shaft 26 drives the cycloidal disc 27 to oscillate, causing the cycloidal disc 27 to roll circumferentially along the circumference of the roller pin 25. In addition to its own rotation, the eccentric shaft 26 rotates together with the cycloidal disc 27 around the rotational axis 31 of the RV mechanism. Each eccentric shaft 26 is connected to the steering gear output shaft 6 via further rolling bearings 32, and the rotational motion of the cycloidal disc 27 around the rotational axis 31 is transmitted to the steering gear output shaft 6 via the eccentric shaft 26.

[0054] Furthermore, each eccentric shaft 26 is technically connected to the first steering gear input shaft 4 via a helical gear mechanism 19. The helical gear mechanism 19 comprises a first helical gear 17, which is coaxially positioned with the steering gear input shaft 4 and indirectly connected to the steering gear input shaft 4 in a manner that prevents relative rotation. The helical gear mechanism 19 further comprises a second helical gear 18, whose oblique external teeth mesh with the oblique external teeth of the first helical gear 17. The axes of rotation of the helical gears 17 and 18 are positioned in a twisted position relative to each other, and the second helical gear 18 rotates around the rotational axis 31 of the cycloidal gear mechanism 20.

[0055] The second helical gear 18 is ring-shaped and has an oblique external tooth row on its outer circumference, which meshes with the oblique external tooth row of the first helical gear 17. The second helical gear 18 has an internal tooth row 54 along its inner circumference, which meshes with the external tooth row 55 of a further eccentric shaft gear 29. The second helical gear 18 is rotatably supported on the steering gear output shaft 6 by a plurality of rolling bearings 33.

[0056] To that extent, the torque path from the first steering gear input shaft 4 to the steering gear output shaft 6 comprises several gear stages that are technically connected in series. One of these gear stages is formed by a helical gear mechanism 19. Another of these gear stages is formed by the meshing of a second helical gear 18, preferably a linear internal tooth row 54, with the external tooth row 55 of an eccentric shaft gear 28. Another of these gear stages is formed by a cycloidal gear mechanism 21. The helical gear 18 forms an intermediate gear 56, which is a component of two gear stages that are technically connected in series.

[0057] The steering gear device housing 7 includes an output shaft bearing housing 34, and a steering gear output shaft bearing 35 and a seal 53 are arranged in the output shaft bearing housing 34 to rotatably support the steering gear output shaft 6.

[0058] The distance 36 from the plane 37 perpendicular to the steering gear output shaft 6, where the rotation axis of the first steering gear input shaft 4 is located, to the plane 38 where the outer portion of the steering gear device housing 7 that directly surrounds the output shaft bearing housing 34 is located, is in the range of 70 mm to 90 mm, and preferably 80 mm.

[0059] The axes of rotation of the first steering gear input shaft 4 and the steering gear output shaft 6 are positioned in planes perpendicular to each other, and these planes have a distance of 80 mm to 100 mm, especially 90 mm, from each other 39.

[0060] Figure 2 shows a first exemplary embodiment of the steering system 1 according to the present invention in a further cross-sectional view.

[0061] As can be seen in Figure 2, the steering gear input shaft 4 has an input portion 40 configured as a solid shaft, a central portion 41 configured as a solid shaft, and a hollow shaft portion 42, the hollow shaft portion 42 forming a first helical gear 17 in part. The central portion 41 is directly connected at one end to the input portion 40 in a way that prevents relative rotation, and at the other end to the hollow shaft portion 42 in a way that prevents relative rotation, and the hollow shaft portion 42 surrounds the central portion 41 and a part of the input portion 40.

[0062] The steering system 1 includes a first rotation angle sensor 43, which detects the rotational position and rotational speed of the input portion 40 of the first steering gear input shaft 4. The steering system 1 further includes a second rotation angle sensor 44, which detects the rotational position of the portion of the hollow shaft portion 42 of the first steering gear input shaft 4 that surrounds the input portion 40. The first rotation angle sensor 43 comprises a first rotary encoder sensor 60 and a first coding element 61, the first coding element 61 cooperating non-contact with the first rotary encoder sensor 60, for example in the form of a graduated disk, a toothed ring, or a magnetic wheel. The second rotation angle sensor 44 comprises a second rotary encoder sensor 62 and a second coding element 63, the second coding element 63 interacting non-contact with the second rotary encoder sensor 62, for example in the form of a graduated disk, a toothed ring, or a magnetic wheel. The first rotary encoder sensor 60 and the second rotary encoder sensor 62 can, advantageously, be arranged together on the same support and / or within the same sensor housing. In the figure, the first rotary encoder sensor 60 and the second rotary encoder sensor 62 are shown together only schematically as a closed polygon indicated by hatching.

[0063] The measurement signals from the first rotary encoder sensor 60 and the second rotary encoder sensor 62 are transmitted to a control device (not shown), which controls the motor 2 taking the measurement signals into consideration. Here, the control device can infer the current torque applied to the first steering gear input shaft 4 by the steering control unit (not shown) from the difference between the rotation angle of the first rotary encoder sensor 60 and the rotation angle of the second rotary encoder sensor 62. This is possible because the input portion 40 where the first coding element 61 is located and the end of the hollow shaft portion 42 where the second coding element 63 is located, which is directly connected to the central portion 41, both belong to the first steering gear input shaft 4, but are technically located before and after the first helical gear 17 of the helical gear mechanism 19. Therefore, when torque is applied, they rotate relative to each other, particularly due to the twisting of the relatively thin central portion 41, and the greater the torque applied to the first steering gear input shaft 4 by the steering control unit (not shown), the greater the difference in rotational angle.

[0064] Advantageously, the control device may be designed to control the motor 2 in accordance with the difference in rotational angles between at least the first rotary encoder sensor 60 and the second rotary encoder sensor 62.

[0065] The steering gear device housing 7 comprises an input shaft bearing housing 45 and a further input shaft bearing housing 46, the further input shaft bearing housing 46 being arranged in mirror symmetry with respect to the horizontal mirror plane of the first input shaft bearing housing. A steering gear input shaft bearing module 47 is arranged in the input shaft bearing housing 45, and the steering gear input shaft bearing module 47 includes a first rolling bearing 58 and a second rolling bearing 59. The input portion 40 is rotatably supported by the first rolling bearing 58. The end of the hollow shaft portion 42 surrounding the input portion 40 is rotatably supported by the second rolling bearing 59.

[0066] Further input shaft bearing housings 46 house additional steering gear input shaft bearing modules 48, each equipped with rolling bearings 64. The ends of the hollow shaft portions 42, which are directly connected to the central portion 41, are rotatably supported by the rolling bearings 64.

[0067] The steering gear input shaft bearing module 47 and the further steering gear input shaft bearing module 48 play a particular role in reliably supporting the first steering gear input shaft 4 in a rotatable manner, and the first rotary encoder sensor 60 and the second rotary encoder sensor 62 are spatially integrated within the steering gear input shaft bearing module 47. The steering gear input shaft 4 protrudes outward through the opening of the input shaft bearing housing 45.

[0068] In contrast, if, for example, a mirror-symmetric steering system 11 for a right-hand drive vehicle is manufactured instead of a steering system 1 which may be configured for a left-hand drive vehicle, the steering gear housing 7 can be used such that the steering gear input shaft 4 protrudes out of the steering gear housing 7 through the opening of a further input shaft bearing housing 46, as shown in Figures 5 to 7.

[0069] Figure 3 shows the steering system 1 in a side view, and Figure 4 shows the steering system 1 in a perspective view. As can be seen from both figures, there are a total of five fixing elements 8, and the fixing elements 8 can be configured as screw holes.

[0070] There are two upper fixing elements 49, two lower fixing elements 50, and one central fixing element 51. The fixing elements 8 are arranged in a mirror-image symmetrical manner with respect to the plane 52 on which the rotation axis 31 and the central fixing element 51 are located.

[0071] As shown in Figures 5 to 7, the steering gear device housing 7 is configured to enable the manufacture of a steering system 11 that is mirror-symmetric to the steering system 1 with respect to the arrangement and orientation of the first steering gear input shaft 4, the second steering gear input shaft 5, the steering gear output shaft 6, and the fixing element 8, particularly with respect to the vertical mirror surface 10. In steering system 1, two upper fixing elements 49 are positioned at the top, whereas in the mirror-symmetric steering system 11, the two upper fixing elements 49 are positioned at the bottom. In steering system 1, two lower fixing elements 50 are positioned at the bottom, whereas in the mirror-symmetric steering system 11, the two lower fixing elements 49 are positioned at the top.

[0072] In steering system 1, the steering gear input shaft 4 protrudes outward through the opening of the input shaft bearing housing 45, whereas in the mirror-symmetric steering system 11, the steering gear input shaft 4 protrudes outward through the opening of an additional input shaft bearing housing 46.

[0073] Figure 8 shows a schematic detail view of the helical gear mechanism 19 and RV mechanism 20 of a first exemplary embodiment of the steering system according to the present invention, where the oblique tooth arrangements of the first helical gear 17 and the second helical gear 18 are not shown for clarity.

[0074] Figure 9 shows a cross-sectional view of a second exemplary embodiment of the steering system 1 according to the present invention.

[0075] The steering system 1 consists of steering system components. The steering system components include at least an electric motor 2, a steering gear device 3 which includes a first steering gear input shaft 4 connectable to a steering shaft (not shown), a second steering gear input shaft 5 driven by the electric motor 2, and a steering gear output shaft 6. The steering system components also include a steering gear housing 7, which comprises a plurality of fixing elements 8 for fixing the steering gear housing 7 to a higher structure, particularly the vehicle body. The fixing elements 8 of the steering gear housing 7 can be configured, for example, as through holes or screw holes 9 for fixing screws.

[0076] The steering gear device housing 7 is configured to enable the manufacture of a steering system 11 that is mirror-symmetric to the steering system 1 with respect to the arrangement and orientation of at least the first steering gear input shaft 4 and the second steering gear input shaft 5, the steering gear output shaft 6, and the fixing element 8, particularly with respect to the vertical mirror surface 10, as shown in Figures 13 to 15 and described in further detail below. Specifically, in this exemplary embodiment, the steering system components are configured such that, when the worm shaft 65 of the worm gear mechanism 67 (which has a worm wheel 66 in addition to the worm shaft 65) enclosed by the steering gear device housing 7 is replaced by an identical worm shaft 65 having the opposite helical direction, a steering system 11 can be manufactured that is mirror-symmetric with respect to the steering system 1 with respect to the mirror surface 10, with respect to the arrangement and orientation of the first steering gear input shaft 4 and the second steering gear input shaft 5, the steering gear output shaft 6, and the fixed element 8.

[0077] Motor 2 is connected to the second steering gear input shaft 5 via a power transmission gear device 12. The power transmission gear device 12 is configured as a spur gear mechanism and includes a first spur gear 13, which is directly connected to the power output shaft 14 of motor 2 in a manner that prevents relative rotation. The power transmission gear unit 12 further comprises a rotatably supported second spur gear 15, the teeth of which mesh with the teeth of the first spur gear 13. The power transmission gear unit 12 further comprises a third spur gear 16, the third spur gear 16 is directly connected to the second steering gear input shaft 5 so as not to rotate relative to it.

[0078] The torque path from the first steering gear input shaft 4 to the steering gear output shaft 6 comprises multiple gear stages connected in series in terms of drive technology. The first gear stage is configured as a helical gear mechanism 19, and the second gear stage, located downstream of the first gear stage in terms of drive technology, is configured as an RV mechanism 20.

[0079] The RV mechanism 20 comprises a cycloidal gear mechanism 21 and an upstream stage 22. The cycloidal gear mechanism 21 is technically connected downstream of the motor 2 via a power transmission gear unit 12 and an upstream stage 22. The cycloidal gear mechanism 21 includes two cycloidal discs 23 and 24, each having a cycloidal external gear row, which meshes with roller pins 25 arranged along the circumference. The movement of the cycloidal discs 23 and 24 is generated by a plurality of eccentric shafts 26, each centered off-center and supported by rolling bearings 27 to rotate relative to the cycloidal discs 23 and 24.

[0080] Each eccentric shaft 26 comprises an eccentric shaft gear 28 and a further eccentric shaft gear 29. The eccentric shaft gear 28 and the further eccentric shaft gear 29 of each eccentric shaft 26 are positioned on opposite sides of the two cycloidal discs 27.

[0081] Further eccentric shaft gears 29 are part of the upstream stage 22. A centrally located second steering gear input shaft 5 has an external gear row 30 that meshes with the external gear row of the further eccentric shaft gears 29. To that extent, the second steering gear input shaft 5 functions as the drive gear 57 of the upstream stage 22, transmitting its rotational motion to the further eccentric shaft gears 29. This causes the eccentric shafts 26 to drive the cycloidal disc 27 into an oscillating motion, in which the cycloidal disc 27 rolls circumferentially along the circumference of the roller pin 25, and the eccentric shafts 26 rotate around the rotational axis 31 of the RV mechanism together with the cycloidal disc 27, in addition to rotating on its own. Each eccentric shaft 26 is connected to the steering gear output shaft 6 via further rolling bearings 32, and the rotational motion of the cycloidal disc 27 around the rotational axis 31 is transmitted to the steering gear output shaft 6 via the eccentric shafts 26.

[0082] Furthermore, each eccentric shaft 26 is driven by a worm gear mechanism 67 to a first steering gear input shaft 4. As already mentioned, the worm gear mechanism 67 comprises a worm shaft 65, which is coaxial with the steering gear input shaft 4 and indirectly connected to the steering gear input shaft 4 in a manner that prevents relative rotation. The worm gear mechanism 67 further comprises a worm wheel 66, the external teeth of which mesh with the worm shaft 65. The axes of rotation of the worm shaft 65 and the worm wheel 66 are positioned in a torsional position relative to each other, and the worm wheel 66 rotates around the rotational axis 31 of the cycloidal gear mechanism 20.

[0083] The worm wheel 66 is ring-shaped and, as already mentioned, has an external gear row on its outer circumference, which meshes with the worm shaft 65. The worm wheel 66 has an internal gear row 54 along its inner circumference, which meshes with the external gear row 55 of a further eccentric shaft gear 29. The worm wheel 66 is rotatably supported relative to the steering gear output shaft 6 by a plurality of rolling bearings 33.

[0084] To that extent, the torque path from the first steering gear input shaft 4 to the steering gear output shaft 6 comprises a plurality of gear stages that are technically connected in series. One of these gear stages is formed by a worm gear mechanism 67. Another of these gear stages is formed by the meshing of a preferably linear internal tooth row 54 of a worm wheel 66 with an external tooth row 55 of an eccentric shaft gear 28. Another of these gear stages is formed by a cycloidal gear mechanism 21. The worm wheel 66 forms an intermediate gear 56, which is a component of two gear stages connected in series in a drive mechanism.

[0085] The steering gear device housing 7 includes an output shaft bearing housing 34, and a steering gear output shaft bearing 35 and a seal 53 are arranged in the output shaft bearing housing 34 to rotatably support the steering gear output shaft 6.

[0086] The distance 36 from the plane 37 perpendicular to the steering gear output shaft 6, where the rotation axis of the first steering gear input shaft 4 is located, to the plane 38 where the outer portion of the steering gear device housing 7 that directly surrounds the output shaft bearing housing 34 is located, is in the range of 70 mm to 90 mm, and preferably 80 mm.

[0087] The axes of rotation of the first steering gear input shaft 4 and the steering gear output shaft 6 are positioned in planes perpendicular to each other, and these planes have a distance of 80 mm to 100 mm, especially 90 mm, from each other 39.

[0088] Figure 10 shows a second exemplary embodiment of the steering system 1 according to the present invention in a further cross-sectional view.

[0089] As can be seen from Figure 10, the steering gear input shaft 4 has an input portion 40 configured as a solid shaft, a central portion 41 configured as a solid shaft, and a hollow shaft portion 42, and this hollow shaft portion 42 forms the first helical gear 17 in one cross-section.

[0090] The central portion 41 is directly connected at one end to the input portion 40 in a manner that prevents relative rotation, and at the other end to the hollow shaft portion 42 in a manner that prevents relative rotation, and the hollow shaft portion 42 surrounds the central portion 41 and a part of the input portion 40.

[0091] The steering system 1 includes a first rotation angle sensor 43, which detects the rotational position and rotational speed of the input portion 40 of the first steering gear input shaft 4. The steering system 1 further includes a second rotation angle sensor 44, which detects the rotational position of the portion of the hollow shaft portion 42 of the first steering gear input shaft 4 that surrounds the input portion 40. The first rotation angle sensor 43 comprises a first rotary encoder sensor 60 and a first coding element 61, the first coding element 61 interacting non-contact with the first rotary encoder sensor 60, for example, in the form of a graduated disk, a toothed ring, or a magnetic wheel. The second rotation angle sensor 44 comprises a second rotary encoder sensor 62 and a second coding element 63, the second coding element 63 interacting non-contact with the second rotary encoder sensor 62, for example in the form of a graduated disk, a toothed ring, or a magnetic wheel. The first rotary encoder sensor 60 and the second rotary encoder sensor 62 can, advantageously, be arranged together on the same support and / or within the same sensor housing. In the figure, the first rotary encoder sensor 60 and the second rotary encoder sensor 62 are shown together only schematically as a closed polygon indicated by hatching.

[0092] The measurement signals from the first rotary encoder sensor 60 and the second rotary encoder sensor 62 are transmitted to a control device (not shown), which controls the motor 2 taking the measurement signals into consideration. Here, the control device can infer the current torque applied to the first steering gear input shaft 4 by the steering control unit (not shown) from the difference between the rotation angle of the first rotary encoder sensor 60 and the rotation angle of the second rotary encoder sensor 62. This is possible because the input portion 40 where the first coding element 61 is located and the end of the hollow shaft portion 42 where the second coding element 63 is located, which is directly connected to the central portion 41, both belong to the first steering gear input shaft 4, but are technically located in front of and behind the worm wheel 66 of the worm gear mechanism 67. Therefore, when torque is applied, they rotate relative to each other, especially due to the twisting of the relatively thin central portion 41, and the larger the torque applied to the first steering gear input shaft 4 by the steering control unit (not shown), the larger the difference in rotation angles.

[0093] Advantageously, the control device may be designed to control the motor 2 in accordance with the difference in rotational angles between at least the first rotary encoder sensor 60 and the second rotary encoder sensor 62.

[0094] The steering gear device housing 7 comprises an input shaft bearing housing 45 and a further input shaft bearing housing 46, the further input shaft bearing housing 46 being arranged in mirror symmetry with respect to the horizontal mirror plane of the first input shaft bearing housing. A steering gear input shaft bearing module 47 is arranged in the input shaft bearing housing 45, and the steering gear input shaft bearing module 47 includes a first rolling bearing 58 and a second rolling bearing 59. The input portion 40 is rotatably supported by the first rolling bearing 58. The end of the hollow shaft portion 42 surrounding the input portion 40 is rotatably supported by the second rolling bearing 59.

[0095] Further input shaft bearing housings 46 house additional steering gear input shaft bearing modules 48, each of which includes rolling bearings 64. The ends of the hollow shaft portions 42, which are directly connected to the central portion 41, are rotatably supported by the rolling bearings 64.

[0096] The steering gear input shaft bearing module 47 and the further steering gear input shaft bearing module 48 play a particular role in reliably supporting the first steering gear input shaft 4 in a rotatable manner, and the first rotary encoder sensor 60 and the second rotary encoder sensor 62 are spatially integrated within the steering gear input shaft bearing module 47. The steering gear input shaft 4 protrudes outward through the opening of the input shaft bearing housing 45.

[0097] In contrast, if, for example, a mirror-symmetric steering system 11 for a right-hand drive vehicle is manufactured instead of a steering system 1 which may be configured for a left-hand drive vehicle, the steering gear housing 7 can be used such that the steering gear input shaft 4 protrudes out of the steering gear housing 7 through the opening of a further input shaft bearing housing 46, as shown in Figures 13 to 15.

[0098] Figure 11 shows the steering system 1 in a side view, and Figure 12 shows the steering system 1 in a perspective view. As can be seen from both figures, there are a total of five fixing elements 8, and the fixing elements 8 can be configured as screw holes.

[0099] There are two upper fixing elements 49, two lower fixing elements 50, and one central fixing element 51. The fixing elements 8 are arranged in a mirror-image symmetrical manner with respect to the plane 52 on which the rotation axis 31 and the central fixing element 51 are located.

[0100] As shown in Figures 13 to 15, the steering gear device housing 7 is configured to enable the manufacture of a steering system 1 and a steering system 11 that are mirror-symmetric with respect to the steering system 1 and the vertical mirror surface 10, with respect to the arrangement and orientation of the first steering gear input shaft 4 and the second steering gear input shaft 5, the steering gear output shaft 6, and the fixing elements 8. In the steering system 1, two upper fixing elements 49 are located at the top, whereas in the mirror-symmetric steering system 11, two upper fixing elements 49 are located at the bottom. In the steering system 1, two lower fixing elements 50 are located at the bottom, whereas in the mirror-symmetric steering system 11, two lower fixing elements 49 are located at the top.

[0101] In steering system 1, the steering gear input shaft 4 protrudes outward through the opening of the input shaft bearing housing 45, whereas in the mirror-symmetric steering system 11, the steering gear input shaft 4 protrudes outward through the opening of an additional input shaft bearing housing 46.

[0102] Figure 16 shows a schematic detail view of the worm gear mechanism 67 and RV mechanism 20 of a second exemplary embodiment of the steering system according to the present invention. For clarity, the external teeth of the worm wheel 66 and the threads of the worm shaft 65 are not shown.

[0103] Figure 17 shows a schematic detail of an exemplary embodiment of a combination of a helical gear mechanism 19 and an RV mechanism 20 for a steering system according to the present invention.

[0104] Unlike the combination of the helical gear mechanism 19 and the RV mechanism 20 shown in Figure 8, the eccentric shaft gear 28 of each eccentric shaft and the further eccentric shaft gear are located on the same side of the two cycloidal discs 27.

[0105] Figure 18 shows a schematic detail of a further exemplary embodiment of the combination of the helical gear mechanism 19 and the RV mechanism 20 for the mirror-symmetric steering system 11 according to the present invention, which is mirror-symmetric with respect to the arrangement and orientation of at least the first steering gear input shaft 4 and the second steering gear input shaft 5, the steering gear output shaft 6, and the fixed element 8, which constitute the combination shown in Figure 17.

[0106] The combination of the helical gear mechanism 19 and the RV mechanism 20 shown in Figure 18 is manufactured from the same components as the combination of the helical gear mechanism 19 and the RV mechanism 20 shown in Figure 17, and is mirror-image symmetric to the combination in Figure 17. However, here, the first helical gear 17 is replaced by a first helical gear 68 which is identical except for having a reverse helical direction, and the second helical gear 18 is replaced by a second helical gear 69 which is identical except for having a reverse helical direction.

[0107] The embodiment shown in Figure 17 can be used, for example, in a left-hand drive vehicle, and the mirror-symmetric embodiment shown in Figure 18 can be used in a right-hand drive vehicle. However, depending on how the rest of the steering and the connections of the steering system within the remaining steering elements in the vehicle are formed, it is also entirely possible to use the combination of the helical gear mechanism 19 and the RV mechanism 20 in a right-hand drive vehicle without replacing the helical gears 17, 18 with identical helical gears 68, 69 except that they have opposite helical directions, as shown in Figure 18. Such a mirror-symmetric combination can be manufactured entirely using the same steering system components as the embodiment shown in Figure 17.

[0108] Figure 19 shows a cross-sectional view of a third exemplary embodiment of the steering system 1 according to the present invention.

[0109] The steering system 1 consists of steering system components. The steering system components include an electric motor 2, a steering gear device 3 which includes a first steering gear input shaft 4 connectable to a steering shaft (not shown), a second steering gear input shaft 5 driven by the electric motor 2, and a steering gear output shaft 6. The steering system components also include a steering gear housing 7, which comprises a plurality of fixing elements 8 for fixing the steering gear housing 7 to a higher structure, particularly the vehicle body. The fixing elements 8 of the steering gear housing 7 can be configured, for example, as through holes or screw holes 9 for fixing screws.

[0110] The steering gear device housing 7 is configured to enable the manufacture of a steering system 11 that is mirror-symmetric to the steering system 1 with respect to the arrangement and orientation of at least the first steering gear input shaft 4 and the second steering gear input shaft 5, the steering gear output shaft 6, and the fixed element 8, particularly with respect to the vertical mirror surface 10, as shown in Figures 22 to 24 and described in more detail below. Specifically, in this exemplary embodiment, the steering system components are configured such that a steering system 11 can be manufactured that is mirror-symmetric with respect to the steering system 1 with respect to the mirror surface 10, with respect to the arrangement and orientation of the first steering gear input shaft 4 and the second steering gear input shaft 5, the steering gear output shaft 6, and the fixed element 8.

[0111] The steering gear device 3 includes a harmonic drive gear mechanism 70 and a further harmonic drive gear mechanism 71, which are technically connected in series in the torque path from the motor 2 to the steering gear output shaft 6.

[0112] Motor 2 is connected to the second steering gear input shaft 5 via a power transmission gear unit 12. The power transmission gear unit 12 is configured as a traction means drive device comprising a traction means 72, a first traction means support 73, and a second traction means support 74. The first traction means support 27 is directly connected to the power output shaft 75 of motor 2 in a manner that prevents relative rotation. The second traction means support 74 is connected to the second steering gear input shaft 5 in a manner that prevents relative rotation.

[0113] The second steering gear input shaft 5 is configured as a hollow shaft and has an elliptical portion 76, which functions as a deformed body of the wave generator 80 of the wave gear mechanism 70 and is rotatably supported by radially flexible rolling bearings 77. The elliptical portion 76 presses the end of the pot-shaped flex spline 78, which has an external tooth row, into an elliptical shape, and engages with the internal tooth row of the circular spline 79 at two meshing positions. The elliptical portion 76, together with the radially flexible rolling bearing 77, forms the wave generator 80 of the wave drive gear mechanism 70.

[0114] The circular spline 79 of the wave drive gear mechanism 70 has an elliptical outer circumference and therefore also functions simultaneously as a modified form of a further wave generator of the further wave drive gear mechanism 71, and is rotatably supported by a further radially flexible rolling bearing 81. The circular spline 79 elliptically presses the end of a further pot-shaped flex spline 82, which has an external tooth row, into the internal tooth row of a further circular spline 83 that is positioned so as not to rotate relative to the steering gear device housing 7, and engages in at least two engagement positions. Further pot-shaped flex splines 82 function as power output sections for further harmonic drive mechanisms 71 and are connected to the steering gear output shaft 6 in a way that prevents relative rotation.

[0115] The torque path from the first steering gear input shaft 4 to the steering gear output shaft 6 comprises multiple gear stages that are technically connected in series. The first gear stage is configured as a bevel gear mechanism 90 comprising a crown gear 91 and a pinion 92. The crown gear 91 is connected to the steering gear input shaft 4 in a relative-rotation-immobile manner. The pinion 92 is connected to a bell-shaped external toothed spur gear 94 via a rotatably supported shaft 93 in a relative-rotation-immobile manner, and the teeth of the spur gear 94 mesh with the teeth of a further rotatably supported spur gear 95. The spur gear 94 and the further spur gear 95 constitute a further gear stage. The further spur gear 95 is connected to a circular spline 79 in a relative-rotation-immobile manner.

[0116] The steering gear device housing 7 includes an output shaft bearing housing 34, and a steering gear output shaft bearing 35 and a seal 53 are arranged in the output shaft bearing housing 34 to rotatably support the steering gear output shaft 6.

[0117] Figure 20 shows a third exemplary embodiment of the steering system 1 according to the present invention in a further cross-sectional view.

[0118] As can be seen from Figure 20, the steering gear input shaft 4 has an input portion 40 configured as a solid shaft, a central portion 41 configured as a solid shaft, and a hollow shaft portion 42. The central portion 41 is directly connected at one end to the input portion 40 in a way that prevents relative rotation, and at the other end to the hollow shaft portion 42 in a way that prevents relative rotation, and the hollow shaft portion 42 surrounds the central portion 41.

[0119] The steering system 1 includes a first rotation angle sensor 43, which detects the rotational position and rotational speed of the input portion 40 of the first steering gear input shaft 4. The steering system 1 further includes a second rotation angle sensor 44, which detects the rotational position of the portion of the hollow shaft portion 42 of the first steering gear input shaft 4 that surrounds the input portion 40. The first rotation angle sensor 43 comprises a first rotary encoder sensor 60 and a first coding element 61, the first coding element 61 interacting non-contact with the first rotary encoder sensor 60, for example, in the form of a graduated disk, a toothed ring, or a magnetic wheel. The second rotation angle sensor 44 comprises a second rotary encoder sensor 62 and a second coding element 63, the second coding element 63 interacting non-contact with the second rotary encoder sensor 62, for example in the form of a graduated disk, a toothed ring, or a magnetic wheel. The first rotary encoder sensor 60 and the second rotary encoder sensor 62 can, advantageously, be arranged together on the same support and / or within the same sensor housing. In the figure, the first rotary encoder sensor 60 and the second rotary encoder sensor 62 are shown together only schematically as a hatched closed polygon.

[0120] The measurement signals from the first rotary encoder sensor 60 and the second rotary encoder sensor 62 are transmitted to a control device (not shown), which controls the motor 2 taking the measurement signals into consideration. Here, the control device can infer the current torque applied to the first steering gear input shaft 4 by the steering control unit (not shown) from the difference between the rotation angle of the first rotary encoder sensor 60 and the rotation angle of the second rotary encoder sensor 62. This is possible because the input portion 40 where the first coding element 61 is located and the end of the hollow shaft portion 42 where the second coding element 63 is located, which is directly connected to the central portion 41, both belong to the first steering gear input shaft 4, but are technically located in front of and behind the worm wheel 66 of the worm gear mechanism 67. Therefore, when torque is applied, they rotate relative to each other, especially due to the twisting of the relatively thin central portion 41, and the larger the torque applied to the first steering gear input shaft 4 by the steering control unit (not shown), the larger the difference in rotation angles.

[0121] Advantageously, the control device may be designed to control the motor 2 in accordance with the difference in rotational angles between at least the first rotary encoder sensor 60 and the second rotary encoder sensor 62.

[0122] The steering gear device housing 7 comprises an input shaft bearing housing 45 and a further input shaft bearing housing 46, the further input shaft bearing housing 46 being arranged symmetrically with respect to the horizontal mirror plane of the input shaft bearing housing 45. A steering gear input shaft bearing module 47 is disposed in the input shaft bearing housing 45, and the steering gear input shaft bearing module 47 comprises rolling bearings 96. The input portion 40 is rotatably supported by the rolling bearings 96.

[0123] Further input shaft bearing housing 46 is provided with a further steering gear input shaft bearing module 48, which comprises two rolling bearings 97 supporting the steering gear input shaft 4.

[0124] The steering gear input shaft bearing module 47 and the further steering gear input shaft bearing module 48 play a particular role in reliably supporting the first steering gear input shaft 4 in a rotatable manner. The steering gear input shaft 4 protrudes outward through the opening of the input shaft bearing housing 45.

[0125] In contrast, if, for example, a mirror-symmetric steering system 11 for a right-hand drive vehicle is manufactured instead of a steering system 1 which may be configured for a left-hand drive vehicle, the steering gear housing 7 can be used such that the steering gear input shaft 4 protrudes out of the steering gear housing 7 through the opening of a further input shaft bearing housing 46, as shown in Figures 22 to 24.

[0126] Figure 20 shows a side view of the steering system 1. It can be seen that there are a total of five fixing elements 8, and that the fixing elements 8 can be configured as screw holes.

[0127] There are two upper fixing elements 49, two lower fixing elements 50, and one central fixing element 51. The fixing elements 8 are arranged in a mirror-image symmetrical manner with respect to the plane 52 on which the rotation axis 31 and the central fixing element 51 are located.

[0128] As shown in Figures 22 to 24, the steering gear device housing 7 is configured to enable the manufacture of a steering system 1 and a steering system 11 that are mirror-symmetric with respect to the steering system 1 and the vertical mirror surface 10, with respect to the arrangement and orientation of the first steering gear input shaft 4 and the second steering gear input shaft 5, the steering gear output shaft 6, and the fixing elements 8. In the steering system 1, two upper fixing elements 49 are located at the top, whereas in the mirror-symmetric steering system 11, two upper fixing elements 49 are located at the bottom. In the steering system 1, two lower fixing elements 50 are located at the bottom, whereas in the mirror-symmetric steering system 11, two lower fixing elements 49 are located at the top.

[0129] In steering system 1, the steering gear input shaft 4 protrudes outward through the opening of the input shaft bearing housing 45, whereas in the mirror-symmetric steering system 11, the steering gear input shaft 4 protrudes outward through the opening of an additional input shaft bearing housing 46. [Explanation of symbols]

[0130] 1. Steering System 2 motors 3. Steering gear system 4. First steering gear input shaft 5. Second steering gear input shaft 6. Steering gear output shaft 7. Steering gear device housing 8 fixed elements 9 screw holes 10 Mirror surface 11. Mirror-symmetry steering system 12 Power transmission gear system 13 First spur gear 14 Power output shaft 15. Second spur gear 16. Third spur gear 17. First helical gear 18. Second helical gear 19. Helical gear mechanism 20 RV Mechanism 21 Cycloidal gear mechanism 22 Upstream stage 23 Cycloidal discs 24 Cycloidal Discs 25 Roller pins 26 Eccentric shaft 27 Rolling bearings 28 Eccentric shaft gear 29 Further eccentric shaft gears 30 External dentition 31 Rotational center axis 32 Further rolling bearings 33 Rolling bearings 34 Output shaft bearing housing 35 Steering gear output shaft bearing 36 distance 37 plane 38 plane 39 distance 40 Input section 41 Central part 42 Hollow shaft section 43. First rotation angle sensor 44. Second rotation angle sensor 45 Input shaft bearing housing 46 Further input shaft bearing housing 47 Steering gear input shaft bearing module 48 Further steering gear input shaft bearing module 49 Upper fixed element 50 Lower fixed element 51 Central fixed element 52 plane 53 Seals 54 Inner teeth 55 External dentition 56 Intermediate gear 57 Drive gear 58 First rolling bearing 59 Second rolling bearing 60 First rotary encoder sensor 61 Second rotary encoder sensor 62 First coding element 63 Second coding element 64 Rolling bearings 65 Worm shaft 66 Worm Wheel 67 Worm gear mechanism 68 First helical gear having a reverse helical direction 69. A second helical gear having the opposite spiral direction. 70. Harmonic drive gear mechanism 71 Further harmonic drive gear mechanism 72 Traction means 73 First traction means support 74 Second traction means support 75 Power output shaft 76 Elliptical section 77. Radially flexible rolling bearing 78 Flex Spline 79 Circular spline 80 Wave Generator 81 Further radially flexible rolling bearings 82 Further Flex Splines 83 Further circular splines 84 Bevel gear mechanism 85 Crown Gear 86 pinion 87 Shaft 88 Spur gear 89 Further spur gears 90 Bevel gear mechanism 91 Crown Gear 92 pinion 93 Shaft 94 Spur gear 95 Further spur gears 96 Rolling bearings 97 Rolling bearings

Claims

1. A steering system comprising steering system components, wherein the steering system components include at least: Electric motor and A steering gear device including a first steering gear input shaft connectable to a steering shaft, a second steering gear input shaft driven by the electric motor, and a steering gear output shaft, A steering gear device housing comprising a plurality of fixing elements for fixing the steering gear device housing to a higher structure, particularly the vehicle body, In a steering system that includes, A steering system characterized in that the steering gear device housing is configured such that it is possible to manufacture a steering system that is mirror-symmetric to the steering system with respect to at least the arrangement and orientation of the first and second steering gear input shafts, the steering gear output shaft, and the fixed elements, particularly with respect to a vertical mirror surface.

2. The steering system according to claim 1, characterized in that the torque path from the first steering gear input shaft to the steering gear output shaft comprises at least two gear stages that are technically connected in series.

3. The steering system according to claim 2, characterized in that at least one of the gear stages is configured as a wave gear mechanism, a cycloidal gear mechanism, an RV mechanism, or a bevel gear mechanism.

4. The steering system according to any one of claims 1 to 3, characterized in that the steering system components are configured such that a steering system can be manufactured that is mirror-symmetric to the steering system with respect to at least the arrangement and orientation of the first and second steering gear input shafts, the steering gear output shaft, and the fixing elements, particularly with respect to a vertical mirror surface.

5. The steering system according to claim 2, characterized in that at least one of the gear stages is configured as a worm gear mechanism, a spindle gear mechanism, or a helical gear mechanism.

6. The steering system according to claim 5, characterized in that when the worm, spindle, and helical gear are all replaced by the same worm, spindle, and helical gear having opposite helical directions, the steering system components are configured such that a steering system mirror-symmetric with respect to the steering system with respect to at least the arrangement and orientation of the first and second steering gear input shafts, the steering gear output shaft, and the fixed elements, particularly with respect to a vertical mirror surface.

7. The steering system according to any one of claims 2 to 6, characterized in that the first gear stage among the gear stages is configured as a bevel gear mechanism, a worm gear mechanism, a spindle gear mechanism, a helical gear mechanism, or a harmonic drive gear mechanism, and the second gear stage, which is technically downstream of the first gear stage, is configured as a cycloidal gear mechanism, an RV mechanism, or a harmonic drive gear mechanism.

8. The steering system according to any one of claims 1 to 7, characterized in that the electric motor is connected to the second steering gear input shaft via a power transmission gear device.

9. The steering system according to claim 8, characterized in that the power transmission gear device is configured as a traction means transmission mechanism, or comprises a traction means transmission mechanism.

10. The steering system according to claim 8, characterized in that the power transmission gear device is configured as a spur gear mechanism or comprises a spur gear mechanism.

11. The steering system according to claim 8, characterized in that the power transmission gear device is configured as a harmonic drive gear mechanism or comprises a harmonic drive gear mechanism.

12. The steering system according to any one of claims 7 to 11, characterized in that the motor is offset in the axial direction with respect to the second gear stage and is arranged particularly parallel to the axis.

13. The steering system according to any one of claims 1 to 12, characterized in that the motor is offset in the axial direction with respect to the steering gear output shaft, and is arranged particularly parallel to the axis.

14. The steering system according to any one of claims 7 to 11, characterized in that the motor is arranged coaxially with respect to the second gear stage.

15. The steering system according to any one of claims 1 to 14, characterized in that the steering gear device housing is composed of a plurality of parts.

16. The steering system according to any one of claims 2 to 15, characterized in that the steering gear device housing surrounds the gear stages which are at least technically connected in series.

17. The steering system according to any one of claims 8 to 16, characterized in that the steering gear device housing surrounds the power transmission gear device.

18. The steering system according to any one of claims 1 to 17, characterized in that the steering gear device housing is provided with at least one input shaft bearing housing for a steering gear input shaft bearing, particularly in an opening in the housing wall.

19. The steering system according to claim 18, characterized in that the steering gear input shaft bearing is arranged in the input shaft bearing housing.

20. The steering gear device housing is provided with at least one additional input shaft bearing housing for a steering gear input shaft bearing, particularly in a further opening in the housing wall. The steering system according to claim 18 or 19, characterized in that the further input shaft bearing housing is configured and arranged in mirror symmetry with respect to the mirror surface, particularly with respect to the horizontal mirror surface, with respect to the input shaft bearing housing.

21. The steering system according to claim 20, characterized in that the steering gear input shaft bearing is arranged in the further input shaft bearing housing.

22. The steering system according to any one of claims 1 to 21, characterized in that the steering gear device housing is provided with at least one output shaft bearing housing for a steering gear output shaft bearing, particularly in an opening in the housing wall.

23. The steering system according to claim 22, characterized in that a steering gear output shaft bearing is arranged in the output shaft bearing housing.

24. The steering system according to claim 22 or 23, characterized in that the distance from a plane perpendicular to the steering gear output shaft on which the rotation axis of the first steering gear input shaft is located to a plane on which the outer portion of the steering gear device housing that directly surrounds the output shaft bearing housing is located is greater than 70 mm, particularly within the range of 70 mm to 90 mm, and particularly 80 mm.

25. The steering gear device housing is further provided with at least one additional output shaft bearing housing for a steering gear output shaft bearing in a further opening in the housing wall, The steering system according to any one of claims 22 to 24, characterized in that the further output shaft bearing housing is configured and arranged in mirror symmetry with respect to the mirror surface, particularly with respect to the horizontal mirror surface, with respect to the output shaft bearing housing.

26. The steering system according to claim 25, characterized in that the steering gear output shaft bearing is arranged in the further output shaft bearing housing.

27. The steering system according to claim 25 or 26, characterized in that the distance from a plane perpendicular to the steering gear output shaft on which the rotation axis of the first steering gear input shaft is located to the plane on which the outer portion of the steering gear device housing that directly surrounds the output shaft bearing housing is located is greater than 70 mm, particularly within the range of 70 mm to 90 mm, and particularly 80 mm.

28. The steering system according to any one of claims 1 to 27, characterized in that the rotation axes of the first steering gear input shaft and the steering gear output shaft are in a torsional position relative to each other.

29. The steering system according to any one of claims 1 to 28, characterized in that the rotation axes of the steering gear input shaft and the steering gear output shaft are arranged in a plane perpendicular to each other.

30. The steering system according to any one of claims 1 to 29, characterized in that the rotation axes of the first steering gear input shaft and the steering gear output shaft are within the range of 80 mm to 100 mm, particularly 90 mm.

31. A steering system according to any one of claims 1 to 30, A steering system comprising: a steering shaft which is operationally connected to the steering control unit and connected to the first steering gear input shaft; and

32. A vehicle, particularly a commercial vehicle, especially a truck or bus, comprising a steering system according to any one of claims 1 to 30, or a steering system according to claim 31.

33. A method for manufacturing a plurality of steering systems, particularly a steering system according to any one of claims 1 to 30, a. A step of providing a steering system component, wherein the steering system component includes: i. Multiple identical electric motors, ii. A plurality of steering gear devices each including a first steering gear input shaft connectable to a steering shaft, a second steering gear input shaft that is technically connected to or connectable to the electric motor, and a steering gear output shaft, iii. A steering gear device housing comprising a plurality of steering gear device housings, each comprising fixing elements for fixing the steering gear device housing to a higher structure, particularly the vehicle body, and configured such that a steering system mirror-symmetric with respect to the steering system and, in particular with respect to the arrangement and orientation of at least the first and second steering gear input shafts, the steering gear output shaft, and the fixing elements, particularly with respect to a vertical mirror surface, is manufactured. b. A method comprising the step of assembling the steering system components to obtain a plurality of steering systems for right-hand drive vehicles and a plurality of steering systems for left-hand drive vehicles.

34. The method according to claim 33, characterized in that the steering system for a left-hand drive vehicle and the steering system for a right-hand drive vehicle are assembled from completely identical steering system components.

35. The steering system for the left-hand drive vehicle and the steering system for the right-hand drive vehicle are assembled from the same steering system components. The method according to claim 33, characterized in that, when the steering system components include a worm, a spindle, and / or a helical gear, the same worm, spindle, and helical gear having opposite helical directions are used for the steering system for a left-hand drive vehicle on the one hand, and for the steering system for a right-hand drive vehicle on the other hand.

36. a. The steering gear device housing is provided with input shaft bearing housings for steering gear input shaft bearings in openings in the housing walls, and with respect to the steering system for a left-hand drive vehicle, the steering gear input shaft bearing is inserted into the input shaft bearing housing. b. The method according to any one of claims 33 to 35, wherein the steering gear device housing is provided with further input shaft bearing housings for steering gear input shaft bearings, each in an opening in the housing wall, and with respect to the steering system for a right-hand drive vehicle, the steering gear input shaft bearing is inserted into the further input shaft bearing housing.

37. a. The steering gear device housing is provided with output shaft bearing housings for steering gear output shaft bearings in openings in the housing walls, and with respect to the steering system for a left-hand drive vehicle, the steering gear output shaft bearing is inserted into the output shaft bearing housing. b. The method according to any one of claims 33 to 36, wherein the steering gear device housing is provided with further output shaft bearing housings for steering gear output shaft bearings, particularly in openings in the housing wall, and with respect to the steering system for a right-hand drive vehicle, the steering gear output shaft bearing is inserted into the further output shaft bearing housing.

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