Wheel suspension of a motor vehicle and motor vehicle with such

Abstract

Wheel suspension (3) of a motor vehicle (1), with a McPherson strut (5) which has a shock absorber (6) with a damper cylinder (7) and a wheel carrier (8) which is firmly connected to the damper cylinder (7) and has a guide joint (9) for connecting at least one wishbone, characterized in that the guide joint (9) is pivotable about a pivot axis (21) oriented in the vehicle's longitudinal direction (X-direction) and is pivotably and lockably fastened to the wheel carrier (8) by means of a guide joint receptacle (17') and by means of a clamping screw (22) arranged in the pivot axis (21), wherein - the guide joint receptacle (17') is fork-shaped with a base body (23) and at least one first and one second prong (24, 25), and wherein the clamping screw (22), passing through corresponding bores (26, 27; 28) of the prongs (24, 25) and of the wheel carrier (8), is axially supported at one end with a screw head (29) on one prong (24, 25) and at the other end by means of a lock nut (30) on the other prong (25, 24), or alternatively - the guide joint receptacle (17') is fork-shaped with a base body (23) and at least one first and one second prong (24, 25), wherein the clamping screw (22), passing through a bore (26, 27; 28) in one prong (24, 25) and in the wheel carrier (8), is axially supported at one end with a screw head (29) on one prong (24, 25) and is screwed at the other end into a corresponding threaded bore of the other prong (25, 24), or alternatively - the guide joint receptacle (17') has a base body (23) with a prong (24, 25), wherein the clamping screw (22), passing through a bore (26, 27) in the prong (24, 25), is axially supported at one end with a screw head (29) on the prong (24, 25) and is screwed at the other end into a corresponding threaded bore of the wheel carrier (8).

Description

[0001] The invention relates to a wheel suspension of a motor vehicle according to the preamble of claim 1. According to claim 6 of the invention, the same further relates to a motor vehicle with such a wheel suspension.

[0002] For some time now, motor vehicles have been equipped with an automatic steering return system to automatically return the wheels to their straight-ahead position at the end of a turn. To achieve this automatic steering return, appropriate torques are required around the steering axis. This is achieved using geometric parameters such as caster angle, yaw angle, and camber, which determine the steering and handling of the vehicle.

[0003] The caster angle is the angle between the steering axis and the vertical (inclination from top to rear of the vehicle). The caster pulls the wheels, which reduces their tendency to wobble. When cornering, additional restoring forces are released which, together with the effect of a splay angle, support the straight-ahead position of the front wheels. The splay angle is the angle by which the steering axis is tilted from top to inward relative to the vertical. This also creates restoring forces that return the wheel to the straight-ahead position after cornering. Camber is the angle of inclination of the wheel to the vertical. The tilt from top to outwards has a positive sign, whereas the tilt from top to inwards has a negative sign. The camber angle changes with the wheel turning angle. Negative camber increases the cornering force of the wheel when cornering.

[0004] DE 10 2017 201 682 A1 discloses a wheel suspension for a vehicle wheel of a two-track vehicle steered around a steering axle. The wheel carrier supports the vehicle wheel and is pivoted to a vehicle body via a control arm at a pivot point on the wheel carrier side. The wheel carrier has a support bracket for a spring / damper unit, which is pivotally mounted on a spring strut dome of the vehicle body by means of a pivot bearing. The pivot bearing, together with the pivot point on the wheel carrier side, defines the steering axis around which the wheel carrier can pivot during wheel steering movements.

[0005] DE 39 38 475 A1 discloses a wheel suspension comprising an upper wishbone connected to a wheel carrier via a joint, which is oriented relative to a wheel's rotational axis, and a lower control arm held in a bearing element, in which a spring strut is simultaneously supported at its lower end. The bearing element comprises a first vertical bearing for the spring strut and a second suspended bearing for the lower control arm. These bearings consist of ball joints and are supported in a ring of the wheel carrier.

[0006] DE 44 26 881 A1 discloses a steerable wheel suspension, particularly for a front wheel, which is equipped with a spring strut axle or a damper strut axle, a wheel carrier connected to the spring or damper strut, and a wishbone connected to the wheel carrier. The wheel carrier is connected to the damper outer tube via a joint, and the damper outer tube is provided with an extension whose free end is connected to both the wishbone and the wheel carrier via another joint.

[0007] DE 819 633 B discloses a suspension for motor vehicle wheels, particularly steering wheels, which are guided independently by means of two linkages. Here, the two linkages are carried by a common support piece, which is designed as a support pin with a substantially vertical pin axis or is elastically supported about a substantially vertical axis of rotation, but whose pin or axis of rotation, however, has a slight inclination to the vertical transverse plane of the motor vehicle. The inclination of the pin or axis of rotation of the support piece, or of the axes of rotation of the linkages, which expediently run perpendicular to this, corresponds in particular to the desired caster angle of the wheel. The support piece, designed as a support pin, is itself mounted in elastic bearings and can simultaneously serve to support the wheel suspension, e.g., a coil spring whose lower end rests against the lower link.

[0008] DE 10 2015 224 851 B4 discloses a motor vehicle wheel suspension comprising a wheel carrier detachably attached to a journal plate of an axle. For fastening the wheel carrier to the journal plate, a rear bearing is provided with reference to a vehicle coordinate system. This bearing is connected to the journal plate for track adjustment via an adjusting device, which allows detachable fastening of the wheel carrier at a selectable distance from the journal plate. The adjusting device has a threaded bushing connected to the journal plate and a sleeve-shaped adjusting screw, which has a stop for the wheel carrier and an outer threaded portion for receiving the adjusting screw within the threaded bushing. For this purpose, the threaded bushing has a first threaded portion.

[0009] DE 10 2017 207 753 A1 discloses a wheel carrier system for a vehicle chassis, comprising a wheel carrier with at least one connection point for a lower and at least one connection point for an upper wishbone. Furthermore, the wheel carrier system comprises at least one actuator and at least one position-changing system operatively connected to at least one of the connection points. The spatial position of the at least one connection point can be changed by means of the at least one position-changing system. Upon a change in the spatial position of the at least one connection point, for example for the lower wishbone, a virtual intersection point of the struts of the lower wishbone is to be actively shifted in the longitudinal or transverse direction of the vehicle, whereby a spread angle and a steering roll radius of the chassis in which the wheel carrier system is used are to be specifically adjusted depending on the driving situation.

[0010] From the generic DE 103 18 537 B4, a wheel suspension of a motor vehicle with a McPherson strut is generally known. The suspension comprises a shock absorber with a damper cylinder and a wheel carrier rigidly connected to the damper cylinder with a guide joint connection for a control arm, in particular a wishbone. A coil spring is arranged around the damper cylinder of the shock absorber.

[0011] Furthermore, it is known from practice that a piston rod of a piston, which is guided axially in the damper cylinder, ends in an upper so-called strut bearing, which allows rotation of the entire shock absorber and is attachable or attached to the body of the vehicle, thus forming a pivot bearing, so to speak. A guide joint is conventionally formed by a ball joint in the manner of a rigid rubber bearing and has a joint pin which, via a bushing, is mounted in a guide joint mount rigidly connected to the wheel carrier. The guide joint creates an articulated connection between the pivot bearing and the wishbone on the chassis side. It compensates for angular changes between the aforementioned components in relation to one another, which occur, for example, when driving due to compression and rebound movements as well as steering movements.Kinematically, a steering axis of the vehicle (also referred to as the spread axis) is formed from an upper kinematic point, namely the upper damper connection point in the area of the aforementioned strut bearing, and a lower kinematic point, namely the connection point for the wishbone or the center point of the guide joint. The position of the steering axis, described by the so-called spread angle "δ" to the main vertical plane "XZ" of the vehicle, determines the steering forces and steering feel. As already explained above, its size also indirectly influences transferable lateral forces when cornering. The position of the upper and lower kinematic points and accordingly also the spread angle "δ" are fixed with regard to the described wheel suspension with McPherson strut.

[0012] Based on this, the object of the invention is to create a wheel suspension for a motor vehicle with a McPherson strut that enables a targeted or variable adjustment of the spread angle "δ". Furthermore, the object of the invention is to provide a motor vehicle with such a wheel suspension.

[0013] The stated object is achieved with the features of claim 1 and 6 respectively. The subclaims describe preferred developments or embodiments of the invention.

[0014] Accordingly, starting from a wheel suspension of a motor vehicle with a McPherson strut, which has a shock absorber with a damper cylinder and a wheel carrier firmly connected to the damper cylinder with a guide joint for connecting at least one wishbone, the stated object is achieved in that the guide joint is pivotable about a pivot axis oriented in the vehicle's longitudinal direction (X-direction) and is pivotably and lockably fastened to the wheel carrier by means of a guide joint holder and by means of a clamping screw arranged in the pivot axis, wherein - the guide joint receptacle is fork-shaped with a base body and at least a first and a second prong, and wherein the clamping screw, passing through corresponding bores of the prongs and the wheel carrier, is axially supported at one end with a screw head on one prong and at the other end by means of a lock nut on the other prong, or alternatively - the guide joint receptacle is fork-shaped with a base body and at least a first and a second prong, wherein the clamping screw, passing through a bore in one prong and in the wheel carrier, is axially supported at one end with a screw head on one prong and is screwed at the other end into a corresponding threaded bore of the other prong, or alternatively - the guide joint mount has a base body with a prong, wherein the clamping screw, passing through a hole in the prong, is axially supported at one end with a screw head on the prong and is screwed at the other end into a corresponding threaded hole in the wheel carrier.

[0015] This feature makes it extremely easy to adjust the spread angle "δ" to suit specific driving characteristics or to adapt to current driving situations. The lower kinematic point follows a curved path during adjustment, resulting in the desired variability of the spread angle "δ" and the variable arrangement of the steering axis or spread axis.

[0016] In order to securely fasten the guide joint to the base body of the guide joint holder and to enable simple assembly and reproducible adjustment of the spreading angle “δ”, the base body has a through-hole for receiving and holding a pin of the guide joint, wherein a longitudinal axis of the through-hole or the pin is arranged orthogonal to the pivot axis of the guide joint or the guide joint holder.

[0017] To further simplify assembly, the pivoting ability of the guide joint relative to the wheel carrier is limited by an upper and a lower stop.

[0018] In extensive tests on the subject matter of the invention, it was found that a maximum swivel angle “α” resulting from the stops of 20° to 30°, preferably 24°, brings particularly good results with regard to the variable adjustment of the spread angle “δ” and the resulting driving and steering behavior of the motor vehicle.

[0019] In order to be able to make the adjustability of the guide joint even more optimal, an actuator can be assigned to the guide joint, which is designed and / or configured to continuously adjust the guide joint relative to the wheel carrier and accordingly a spread angle “δ” of the wheel suspension as a function of or on the basis of sensed current or predetermined driving conditions and / or on the basis of a predetermined driving destination of the motor vehicle and a resulting, known state of the driving plan of the motor vehicle.

[0020] The object is further achieved according to the invention by a motor vehicle with a wheel suspension of the type described above.

[0021] The invention is explained in more detail below with reference to an exemplary embodiment shown schematically in the drawings. However, it is not limited to this embodiment, but covers all configurations defined by the patent claims. For the purposes of the present description, the usual direction of travel of a motor vehicle is denoted by "-x" ("minus x"), the direction opposite to its usual direction of travel is denoted by "+x" ("plus x"), starting from the usual direction of travel (-x) the horizontal direction perpendicular to the x-direction to the right is denoted by "+y", starting from the usual direction of travel (-x) the horizontal direction perpendicular to the x-direction to the left is denoted by "-y", the vertical direction perpendicular to the x-direction upwards is denoted by "+z", and the vertical direction perpendicular to the x-direction downwards is denoted by "-z".This Cartesian coordinate system for spatial directions corresponds to the coordinate system commonly used in the automotive industry. Furthermore, terms such as "front," "rear," "top," "bottom," and similarly connoted terms, including "right" and "left," are used in the manner commonly used to indicate directions on a motor vehicle. The figures show: Fig. 1 shows a very schematic side view of a motor vehicle with a wheel suspension according to the well-known McPherson principle, Fig. 2 a perspective view of such a wheel suspension according to the state of the art, Fig. 3 the detail “Z” according to Fig. 2 with the representation of a guide joint of the wheel suspension held by a guide joint holder (state of the art), Fig. 4 the detail “Z” according to Fig. 3 in a partial longitudinal section (state of the art), Fig. 5 the detail “Z'” according to Fig. 2 of a wheel suspension designed according to the invention with a guide joint mount including a guide joint pivotably mounted on a wheel carrier thereof, Fig. 6 the detail “Z'” according to Fig. 5 in a partial longitudinal section, Fig. 7 an exploded view of the guide joint holder including the guide joint according to Fig. 5 or 6 of the wheel suspension, and Fig. 8a-8c show the guide joint mount including the guide joint of the wheel suspension designed according to the invention in three different pivoting positions.

[0022] Fig. 1 shows a very schematic view of a motor vehicle 1 in the form of a passenger car, which is front-wheel drive and whose wheels 2 (front wheels) are supported on the body 4 of the motor vehicle 1 by means of a wheel suspension 3 according to the known McPherson principle. Fig. 2, the wheel suspension 3 of, for example, the front left wheel 2 (front wheel) comprises a McPherson strut 5, which has a shock absorber 6 with a damper cylinder 7 and a wheel carrier 8, which is firmly connected to the damper cylinder 7, with a guide joint 9 for connecting at least one wishbone (not shown in the drawing). Fig. 2 also shows a brake disc 10, which is pivotally mounted on the wheel carrier 8. Associated with the brake disc 10 is a brake caliper 11, which is also attached to the wheel carrier 8 and has brake pads. A coil spring 12 is arranged around the damper cylinder 7 of the shock absorber 6. A piston rod 13, which is axially guided in the damper cylinder 7 and of a piston (not shown in the drawing and also guided in the damper cylinder 7), ends in an upper elastic bearing, which allows rotation of the entire shock absorber 6 and is attachable or attached to the body 4 of the motor vehicle 1 and is also referred to as a strut bearing 14. This forms a pivot bearing for the McPherson strut 5 for mounting the same on the body 4 of the motor vehicle 1.

[0023] According to the Fig. 3 and Fig. 4, the guide joint 9 is formed by a ball joint in the manner of a rigid rubber bearing with a fastening means for the wishbone (not shown in the drawing). The fastening means comprises, for example, a retaining plate 9a with fastening screws 9b. The guide joint 9 also has a pin 15, which is mounted, via a bushing 16, in a guide joint receptacle 17 rigidly connected to the wheel carrier 8 and having a bearing eye or through-bore 31, and is axially fixed by means of a lock nut 32.

[0024] As already explained in the introduction, the guide joint 9 creates a jointed connection between the pivot bearing and the wishbone on the chassis side. It compensates for angular changes between the aforementioned components, which occur, for example, during driving due to compression and rebound movements as well as steering movements.

[0025] Kinematically, a steering axis 18 of the motor vehicle 1 (also referred to as the spread axis) is to be noted here, which is formed from an imaginary connecting line between an upper kinematic point 19, namely the upper damper connection point in the area of the said strut bearing 14, and a lower kinematic point 20, namely the connection point for the wishbone or the guide joint center point (cf. Fig. 2).

[0026] The position of the steering axis 18 is described by the so-called spread angle “δ” to the vertical main plane “XZ” of the motor vehicle 1 (cf. Fig. 1 and Fig. 2) determines the steering forces and the steering feel. Its size also indirectly influences transmissible lateral forces when cornering. The position of the upper (19) and lower kinematic point 20 and accordingly also the angle of spread "δ" are fixed with regard to the described wheel suspension 3 with McPherson strut 5 according to the state of the art, in that the guide joint mount 17 is / is formed integrally by the wheel carrier 8 (cf. in particular Fig. 2 to 4).

[0027] In order to enable a targeted or variable adjustment of the spread angle “δ” with regard to predetermined driving characteristics or in adaptation to currently occurring driving situations, in contrast to the prior art, the guide joint 9 is pivotable about a pivot axis 21 oriented in the vehicle longitudinal direction (X direction) and is fastened to the wheel carrier 8 in a manner that can be locked in the selected pivot position.

[0028] For this purpose, the guide joint 9 is pivotably and lockably fastened to the wheel carrier 8 by means of a guide joint holder 17' and by means of a clamping screw 22 arranged in the pivot axis 21 (cf. Fig. 5 to 8c). According to the preferred first embodiment of the invention shown, the guide joint receptacle 17' is fork-shaped with a base body 23 and with at least one first (24) and one second prong 25 such that the two prongs 24, 25 protrude from the base body 23 at a distance from one another.

[0029] In assembly, the clamping screw 22 passes through corresponding holes 26, 27; 28 of the prongs 24, 25 and the wheel carrier 8, whereby the wheel carrier 8 has an extension 8a for this purpose (cf. in particular Fig. 7) with said bore 28, which extension 8a is positioned between the two prongs 24, 25. The clamping screw 22 is axially supported at one end by a screw head 29 on one prong, according to this embodiment, the first prong 24, and at the other end by means of a lock nut 30 screwed onto the free end of the clamping screw 22 on the other prong, in this case the second prong 25.

[0030] According to an alternative embodiment of the invention not shown in the drawing, the clamping screw 22 passes through corresponding bores 26; 28 in one, for example the first prong 24, and in the wheel carrier 8 and is supported axially at one end with a screw head 29 on the one or first prong 24 and is screwed at the other end into a corresponding threaded bore of the other, second prong 25.

[0031] According to a further alternative embodiment of the invention, not shown in the drawing, the guide joint receptacle 17' has a base body 23 with a prong 24 or 25, wherein the clamping screw 22 passes through a bore 26, 27 in the prong 24 or 25 and is axially supported at one end with a screw head 29 on the prong 24 or 25 and is screwed at the other end into a corresponding threaded bore of the wheel carrier 8.

[0032] The base body 23 has a through-bore 31 for receiving and holding the above-mentioned pin 15 of the guide joint 9. The pin 15 passes through the through-bore 31 together with the recessed bushing 16 and is axially fixed to the base body 23 by means of a lock nut 32. According to this embodiment, the longitudinal axis 33 of the through-bore 31 or of the pin 15 is arranged orthogonally to the pivot axis 21 of the guide joint 9 or the guide joint receptacle 17'.

[0033] The pivotability of the guide joint 9 or the guide joint mount 17' relative to the wheel carrier 8 is limited by an upper (34) and a lower stop 35. In extensive tests on the subject matter of the invention, it was found that a maximum pivot angle "α" resulting from the stops of 20° to 30°, preferably 24°, produces particularly good results with regard to the variable adjustment of the spread angle "δ" and the resulting driving and steering behavior of the motor vehicle 1.

[0034] For a better understanding of the invention, the Fig. 8a to 8c show the guide joint mount 17' including the guide joint 9 of the wheel suspension 3 in three different pivot positions. Fig. 8a, the guide joint holder 17' rests against the upper stop 34, which corresponds to a swivel angle “α” of 0°. In Fig. 8c, the guide joint holder 17' rests against the lower stop 35, which corresponds to a swivel angle “α” of 24°. Fig. In contrast, Figure 8b shows an intermediate position of the guide joint mount 17' with a pivot angle "α" of 12°. It will certainly be readily apparent to a person skilled in the art that the lower kinematic point 20 moves in an arcuate path around the pivot axis 21 during the adjustment of the guide joint mount 17' (cf. Fig. 6).

[0035] The embodiment described above is based on an adjustment of the guide joint 9 or the lower kinematic point 20 and accordingly the spread angle “δ”, which is preferably carried out manually by, for example, according to the preferred first embodiment of the invention, slightly loosening the lock nut 30, pivoting the guide joint 9 relative to the wheel carrier 8 to the desired extent and subsequently tightening the lock nut 30 again to lock the guide joint 9 in the selected pivot position on the wheel carrier 8.

[0036] Alternatively, however, it can also be provided and is accordingly also covered by the invention that the guide joint 9 is assigned an actuator which is operated electrically, electromechanically, pneumatically or hydraulically, for example, and which, for example by means of a programmable logic controller of the motor vehicle 1 as a function of or on the basis of sensed current driving conditions and / or on the basis of a predetermined destination of the motor vehicle 1 and a resulting, known state of the driving plan of the motor vehicle 1, continuously adjusts the guide joint 9 or the lower kinematic point 20 and accordingly the spread angle “δ” and thus advantageously influences the driving behavior of the motor vehicle 1 (not shown in the drawing).The actuator can be formed, for example, by a servo motor which is designed to set the currently most advantageous pivoting position of the guide joint holder 17' together with the guide joint 9 relative to the wheel carrier 8 and accordingly the currently most advantageous spreading angle "δ" and, if necessary, to lock the guide joint holder 17' together with the guide joint 9 in this pivoting position (not shown in the drawing). List of reference symbols 1 motor vehicle 2 wheels 3 Wheel suspension 4 Body 5 McPherson strut 6 shock absorbers 7 damper cylinders 8 wheel carriers 8a Extension 9 Guide joint 9a Holding plate 9b Fixing screw 10 brake disc 11 Brake caliper 12 coil spring 13 Piston rod 14 strut mounts 15 cones 16 socket 17 Guide joint mount 17' guide joint mount 18 Steering axle 19 upper kinematic point 20 lower kinematic point 21 Swivel axis 22 clamping screw 23 basic bodies 24 first prong 25 second prong 26 Hole (Teeth 24) 27 Hole (prong 25) 28 Hole (Wheel Carrier 8) 29 Screw head 30 Lock nut 31 through hole 32 Lock nut 33 Longitudinal axis (through hole 31 / pin 15) 34 upper stop 35 lower stop “δ” spread angle “XZ” vertical main plane (vehicle 1) “α” swivel angle

Claims

[1] Wheel suspension (3) of a motor vehicle (1), with a McPherson strut (5) which has a shock absorber (6) with a damper cylinder (7) and a wheel carrier (8) fixedly connected to the damper cylinder (7) with a guide joint (9) for connecting at least one wishbone, characterized by that the guide joint (9) is pivotable about a pivot axis (21) oriented in the vehicle's longitudinal direction (X-direction) and is pivotably and lockably fastened to the wheel carrier (8) by means of a guide joint receptacle (17') and by means of a clamping screw (22) arranged in the pivot axis (21), wherein - the guide joint receptacle (17') is fork-shaped with a base body (23) and at least one first and one second prong (24, 25), and wherein the clamping screw (22), passing through corresponding bores (26, 27; 28) of the prongs (24, 25) and of the wheel carrier (8), is axially supported at one end with a screw head (29) on one prong (24, 25) and at the other end by means of a lock nut (30) on the other prong (25, 24), or alternatively - the guide joint receptacle (17') is fork-shaped with a base body (23) and at least one first and one second prong (24, 25), wherein the clamping screw (22), passing through a bore (26, 27; 28) in one prong (24, 25) and in the wheel carrier (8), is axially supported at one end with a screw head (29) on one prong (24, 25) and is screwed at the other end into a corresponding threaded bore of the other prong (25, 24), or alternatively - the guide joint receptacle (17') has a base body (23) with a prong (24, 25), wherein the clamping screw (22), passing through a bore (26, 27) in the prong (24, 25), is axially supported at one end with a screw head (29) on the prong (24, 25) and is screwed at the other end into a corresponding threaded bore of the wheel carrier (8). [2] Wheel suspension (3) according to claim 1, characterized by that the base body (23) of the guide joint receptacle (17') has a through-bore (31) for receiving and holding a pin (15) of the guide joint (9), wherein the longitudinal axis (33) of the through-bore (31) or of the pin (15) is arranged orthogonally to the pivot axis (21) of the guide joint (9) or of the guide joint receptacle (17'). [3] Wheel suspension (3) according to one of the preceding claims, characterized bythat the pivotability of the guide joint (9) relative to the wheel carrier (8) is limited by an upper (34) and a lower stop (35). [4] Wheel suspension (3) according to claim 3, characterized by that a maximum pivot angle “α” resulting from the stops (34, 35) of 20° to 30°, preferably 24°, is provided. [5] Wheel suspension (3) according to one of the preceding claims, characterized by in that the guide joint (9) is assigned an actuator which is designed and / or configured to continuously adjust the guide joint (9) relative to the wheel carrier (8) and accordingly a spread angle “δ” of the wheel suspension (1) as a function of or on the basis of sensed current or predetermined driving conditions and / or on the basis of a predetermined driving destination of the motor vehicle (1) and a resulting, known state of the driving plan of the motor vehicle (1). [6] Motor vehicle (1) with a wheel suspension (3) according to one of the preceding claims.

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