Corner module and vehicle

Abstract

Corner module (1) for individual steering of a vehicle wheel (6), comprising a main shaft (2) defining a steering axis of rotation of the corner module (1), a steering mechanism (9) and a steering motor (10), wherein the steering motor (10) is configured to rotate the main shaft (2) about the steering axis of rotation via the steering mechanism (9), characterized in that the steering mechanism (9) comprises a ball screw (12) arranged perpendicular to the steering axis of rotation, wherein a longitudinal movement of a nut (13) arranged on the ball screw (12) causes a steering rotation movement of the corner module (1).

Description

The present invention relates to a corner module for the individual steering of a vehicle wheel, comprising a main shaft defining a steering axis of rotation of the corner module, a steering mechanism, and a steering motor, wherein the steering motor is configured to rotate the main shaft about the steering axis of rotation via the steering mechanism. The invention further relates to a vehicle comprising at least one such corner module. Such a corner module is known, for example, from GB 2582640 A. There, a drive arrangement is disclosed which includes a vehicle-mountable connector rotatably coupled to a mounting arm to enable its rotation, which is substantially perpendicular to the longitudinal and transverse axes of the vehicle. The arrangement includes an electric motor whose stator is coupled to the mounting arm, the axis of the motor's rotor being substantially perpendicular to the axis of rotation of the connector, and the rotor being coupled to a vehicle wheel so that the electric motor drives the vehicle wheel. Corner modules of this type typically have a very large height, which takes up a lot of space in the vehicle body and thus severely limits their possible uses. In particular, corner modules that allow a large steering angle require significantly more installation space for the wheel swivel range than conventional wheel suspensions. The invention is therefore based on the objective of providing a corner module of the type mentioned above that allows for a lower overall height. According to the invention, this problem is solved by a corner module of the type mentioned above, characterized in that the steering mechanism comprises a ball screw arranged perpendicular to the steering axis of rotation, wherein a longitudinal movement of a nut arranged on the ball screw causes a steering rotation of the corner module. Such a corner module allows for a compact design of the steering mechanism, meaning that the corner module occupies less space in the vehicle body, especially vertically. At the same time, the steering motor can be smaller than with a direct connection between the steering motor and the main shaft. Preferred embodiments and further developments of the invention can be found in the respective dependent claims. According to a preferred embodiment of the invention, the nut engages in a rack that is movable parallel to the ball screw, so that the rack is moved along the screw axis when the nut moves. This allows the dimensions of the rack and the nut to be decoupled, and in particular, the relatively complex and expensive nut of the ball screw can be made relatively short in the axial direction without limiting the length of the rack and thus the maximum steering angle. Preferably, the corner module includes a sensor for determining the position of the nut and / or a sensor for determining the position of the rack. Preferably, the rack engages with a pinion that is rotationally fixed to the main shaft, so that a translational movement of the rack causes a rotational movement of the main shaft. This allows for a stable connection between the steering mechanism and the main shaft without requiring the steering motor to be arranged coaxially around the main shaft. In one embodiment, the rack is guided in a guide so that it can only move along a displacement path parallel to the ball screw. This prevents the rack from twisting or tilting relative to the ball screw and the main shaft. The movement of the rack can be limited by mechanical stops. Preferably, the guidance is provided from at least two sides by housing walls of a steering mechanism housing. Preferably, these are two opposing housing walls, more preferably an upper and a lower housing wall. According to a further embodiment, the guide on at least one side of the rack includes rollers which support translation of the rack along the guide. This design allows for the smoothest possible movement of the rack and thus also reduces friction losses in the steering mechanism. Preferably, one drive axis of the steering motor is arranged perpendicular to the axis of rotation of the corner module. This also allows for the lowest possible overall height of the steering mechanism and thus of the corner module. The drive axis can then, for example, be arranged parallel to the ball screw. Preferably, the steering motor is connected to the ball screw via a transmission, in particular a belt drive or a gear drive. This makes it possible to arrange the steering motor and the steering mechanism around the main shaft in the most space-saving way possible and to limit the maximum extension in one direction. Preferably, the steering motor and the ball screw are arranged at least partially on opposite sides of the main shaft. This allows for a compact steering mechanism with a low overall height, since the steering motor and ball screw can be arranged at the same height. In one embodiment, the nut has an anti-rotation section designed to prevent rotation of the nut relative to the rack. The nut is preferably connected to the rack in such a way that rotation of the nut is prevented, but no radial stresses are introduced into the ball screw. The anti-rotation section can, for example, be formed by a rectangular cross-section of the nut. Preferably, the anti-rotation section engages in a recess in the rack, so that the rack is displaced along the spindle axis in both directions when the nut is moved. The recess can, for example, be a notch in the rack running perpendicular to the longitudinal axis of the ball screw. In one embodiment, the main shaft has at least one bearing above and one bearing below the pinion relative to the steering mechanism. This supports the main shaft on both axial sides of the steering engagement. Preferably, at least one bearing comprises a ball bearing. Preferably, a bearing with a double ball bearing is arranged above the steering mechanism. Particularly preferably, at least one bearing is a radial-axial bearing. Preferably, the steering mechanism is configured to allow a rotation of the main shaft by at least 120°, preferably by at least 150°, and particularly preferably by at least 180°. By incorporating a ball screw arranged perpendicular to the steering axis, and especially also a rack and pinion, a wide-angle steering system can be achieved in a space-saving manner. Preferably, the main shaft is connected to a main arm of the corner module, wherein a joint suspension is attached to the main arm, which is configured for connection to a vehicle wheel with a brake unit, preferably with a drive-brake unit (e.g., an electric wheel hub motor with integrated disc brake), and / or a suspension is attached, which is configured to cushion a connected vehicle wheel relative to a vehicle body. The solution according to the invention is particularly suitable for such multifunctional corner modules, since these require more installation space / wheel pivot space compared to a conventional wheel suspension, and thus any space saving is particularly advantageous. In a further aspect of the invention, a vehicle is provided comprising at least one, preferably one, two, or four, individually steerable corner modules according to one of the preceding embodiments. Such a vehicle can be steered with particular flexibility and allows for a variety of body concepts. A single corner module according to the invention can be used for steering a three-wheeled vehicle, in particular for the front wheel. Further details of the invention will become apparent from the description of the illustrated embodiments and the attached claims. The drawings show: Fig. 1 an embodiment of a corner module according to the invention, Fig. 2 a view of the steering elements of the corner module according to Fig. 1, and Fig. 3 a sectional view through the steering elements of the corner module according to Fig. 2. In the following detailed description of preferred embodiments, the same reference numerals denote essentially identical or identical parts in or on these embodiments. However, for better clarity of the invention, the preferred embodiments shown in the figures are not always drawn to scale. Fig. 1 shows an embodiment of a corner module 1 according to the invention, comprising a main shaft 2 connected to a main arm 3 of the corner module 1. A pivot suspension 4 is attached to the main arm 3 and is configured for connection to a vehicle wheel 6 with a drive-brake unit. A brake unit 7 (here, by way of example, designed as a disc brake) can be partially connected to the pivot suspension and partially to a rotor of the drive unit (not shown in detail here, for example, an electric wheel hub motor). A suspension 5 is attached to the main arm and to the pivot suspension 4 and is configured to cushion the connected vehicle wheel 6 relative to a vehicle body (not shown). The Corner Module 1 is designed for the individual steering of the vehicle wheel 6. The main shaft 2 defines a steering axis of rotation for the Corner Module 1. A steering mechanism housing 8 is rigidly connected to the vehicle body / chassis for this purpose. Preferably, power supply cables and / or signal cables and / or fluid hoses (for coolant or brake fluid) are routed through the main arm 3 and the main shaft 2 to the vehicle wheel 6 and / or to the wheel hub motor and / or to the brake unit 7. As shown in more detail in Fig. 2 and Fig. 3, the Corner module 1 comprises a steering mechanism 9, which is arranged in the steering mechanism housing 8 (in Fig. 2 only the lower half of the steering mechanism housing 8 is shown), and a steering motor 10. The steering motor 10 is configured to rotate the main shaft 2 about the steering axis via the steering mechanism 9. The steering motor 10 can be controlled via a signal received from a control unit. For example, the exact rotational position of the main shaft in relation to the vehicle's direction of travel can be determined (with suitable calibration) via an encoder located inside the housing of the steering motor 10. The steering motor can be a non-self-locking electric motor, which enables the vehicle wheel 6 to self-straighten, particularly when driving downhill. This saves drive energy for the steering motor 10 and reduces wear. Preferably, the corner module is designed to be installed on the vehicle with a caster angle (i.e., with a slight upward tilt of the corner module against the direction of travel), so that (together with the non-self-locking electric motor) the connected vehicle wheel 6 self-straightens when the steering motor 10 is switched off while driving. A rotary motion generated by the steering motor 10 is transmitted via a gearbox 11 to a ball screw 12 arranged perpendicular to the steering axis. Alternatively, the gearbox 11 can also be designed as a gear drive or chain, or comprise both. A longitudinal movement of a nut 13 arranged on the ball screw 12 causes a steering rotation of the corner module 1. The nut 13 engages with a rack 14 that is movable parallel to the ball screw 12, so that the rack 14 is moved along the screw axis when the nut 13 moves. This allows the dimensions of the rack 14 and the nut 13 to be decoupled, and in particular, the relatively complex and expensive nut 13 of the ball screw 12 can be made relatively short in the axial direction without limiting the length of the rack 14 and thus the maximum steering angle. The rack 14 engages with a pinion 15 which is non-rotatably connected to the main shaft 2, so that a translational movement of the rack 14 causes a rotational movement of the main shaft 2. The rack 14 is guided in a guide 16, so that the rack 14 can only move along a linear displacement path parallel to the ball screw 12. This prevents the rack 14 from twisting or tilting relative to the ball screw 12 and the main shaft 2. The guide 16 is formed at least partially by housing walls of the steering mechanism housing 8 on at least two sides. Here, these are two opposing housing walls, an upper and a lower housing wall of the steering mechanism housing 8. The drive axis of the steering motor 10 is arranged perpendicular to the axis of rotation of the corner module 1. This results in a low overall height for the steering mechanism 9 and thus for the corner module 1. The drive axis is also parallel to the ball screw 12 and at least partially located on opposite sides of the main shaft 2. This allows for a compact steering mechanism 9 with a low overall height. The nut 13 has an anti-rotation section 17, which is designed to prevent rotation of the nut 13 relative to the rack 14. The anti-rotation section 17 is formed here by a rectangular cross-section of the nut 13. The anti-rotation section 17 engages in a recess 18 of the rack 14, so that the rack 14 is displaced along the spindle axis in both directions when the nut 13 is moved. The recess 18 can, for example, be a notch in the rack 14 extending perpendicular to the longitudinal axis of the ball screw 12, into which part of the anti-rotation section 17 engages. As shown in Fig. 3, the main shaft 2 has at least one bearing 19, 20, preferably a radial-axial bearing, above and below the pinion 15, opposite the steering mechanism 9. Radial-axial bearings absorb both radial and axial loads on the main shaft. Thus, the main shaft 2 is supported on both axial sides of the steering engagement. Both bearings 19, 20 comprise ball bearings. Above the steering mechanism 9, the bearing 19 comprises a double ball bearing. The pinion 15 is formed here as a single piece with the main shaft 2, particularly for optimal power transmission. Alternatively, however, it is also possible to provide the pinion 15 as a separate component that is securely attached to the main shaft 2 to prevent rotation. The Corner Module 1 can include its own control unit, e.g., on or in the steering mechanism housing 8, on or in the main arm 3, or in the vehicle wheel 6 (e.g., integrated into the wheel hub motor). Alternatively, one or more Corner Modules 1 can also be controlled by one or more control units of the vehicle. The Corner module 1 can include one or more sensors for determining the steering angle, for example a position sensor for the rack 14 or an angle sensor for the main shaft 2 or for the pinion 15. Reference symbol list 1 Corner module 2 Main shaft 3 Main arm 4 Joint suspension 5 Suspension 6 Vehicle wheel 7 Brake unit 8 Steering mechanism housing 9 Steering mechanism 10 Steering motor 11 Gearbox 12 Ball screw 13 Nut 14 Rack 15 Pinion 16 Guide 17 Anti-rotation section 18 Recess 19 Bearing 20 Bearing

Claims

Corner module (1) for individual steering of a vehicle wheel (6), comprising a main shaft (2) defining a steering axis of rotation of the corner module (1), a steering mechanism (9) and a steering motor (10), wherein the steering motor (10) is configured to rotate the main shaft (2) about the steering axis of rotation via the steering mechanism (9), characterized in that the steering mechanism (9) comprises a ball screw (12) arranged perpendicular to the steering axis of rotation, wherein a longitudinal movement of a nut (13) arranged on the ball screw (12) causes a steering rotation movement of the corner module (1). Corner module (1) according to claim 1, characterized in that the nut (13) engages in a rack (14) movable parallel to the ball screw (12), such that the rack (14) is moved along the spindle axis when the nut (13) is moved. Corner module (1) according to claim 2, characterized in that the rack (14) engages in a pinion (15) which is non-rotatably connected to the main shaft (2), such that a translational movement of the rack (14) causes a rotational movement of the main shaft (2). Corner module (1) according to one of claims 1 to 3, characterized in that the rack (14) is guided in a guide (16) so that the rack (14) can only be moved along a displacement path parallel to the ball screw (12). Corner module (1) according to claim 4, characterized in that the guide (16) is formed on at least two sides by housing walls of a steering mechanism housing (8). Corner module (1) according to claim 4 or 5, characterized in that the guide (16) comprises rollers on at least one side of the rack (14) which support a translation of the rack (14) along the guide (16). Corner module (1) according to one of the preceding claims, characterized in that a drive axis of the steering motor (10) is arranged perpendicular to the axis of rotation of the corner module (1). Corner module (1) according to one of the preceding claims, characterized in that the steering motor (10) is connected to the ball screw (12) via a transmission (11), in particular a belt transmission or a gear transmission. Corner module (1) according to one of the preceding claims, characterized in that the steering motor (10) and the ball screw (12) are arranged at least partially on opposite sides of the main shaft (2). Corner module (1) according to one of the preceding claims, characterized in that the nut (13) has an anti-rotation section (17) which is configured to prevent rotation of the nut (13) relative to the rack (14). Corner module (1) according to claim 10, characterized in that the anti-rotation section (17) engages in a recess of the rack (14) so ​​that the rack (14) is moved along the spindle axis (12) in both directions when the nut (13) is moved. Corner module (1) according to any one of claims 3 to 11, characterized in that the main shaft (2) has at least one bearing (19, 20) above and below the pinion (15) in relation to the steering mechanism (9). Corner module (1) according to one of the preceding claims, characterized in that the steering mechanism (9) is configured to allow a rotation of the main shaft (2) by at least 120°, preferably by at least 150°, particularly preferably by at least 180°. Corner module (1) according to any one of claims 2 to 13, characterized in that the main shaft (2) is connected to a main arm (3) of the corner module (1), wherein a joint suspension (4) is attached to the main arm (3), which is configured for connection with a vehicle wheel (6) with brake unit (7), preferably with drive-brake unit, and / or a suspension (5) is attached, which is configured to cushion a connected vehicle wheel (6) relative to a vehicle body. Vehicle comprising at least one, preferably one, two or four, individually steerable Corner Modules (1) according to one of the preceding claims.

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