Suspension of a motor-vehicle steering wheel provided with an articulation element defining a steering axis

Abstract

It is described a suspension of a motor-vehicle steering wheel, comprising: - a wheel upright (1), - a oscillating arm (3) connectable to a motor-vehicle frame portion, - wherein said oscillating arm (3) comprises an end portion (6) pivotally connected to the wheel upright (1) by means of an articulation element (7) defining a translation and steering axis (X) around which the wheel upright (1) is rotatably mounted, - wherein said articulation element (7) comprises a substantially cylindrical central body (7') engaged within a substantially cylindrical articulation seat (8), and terminal ends (9', 10') protruding from the articulation seat (8) and connected to respective portions (1', 1") of said wheel upright (1), - said suspension further comprising an electric actuator (11) operatively connected to a rack and pinion system (12) comprising a rack (14) directly formed along said central body (7'), configured for sliding the articulation element (7) along the axial direction, so as to modulate a vertical displacement of the wheel upright (1) and consequently vary the motor-20 vehicle ground clearance.

Description

[0001] “Suspension of a motor-vehicle steering wheel provided with an articulation element defining a steering axis”

[0002] ****

[0003] TEXT OF THE DESCRIPTION

[0004] Field of the invention

[0005] The present invention refers to a suspension of a motor-vehicle steering wheel, comprising:

[0006] - a wheel upright,

[0007] - an oscillating arm connectable to a motor-vehicle frame portion,

[0008] - wherein said oscillating arm comprises an end portion pivotally connected to the wheel upright by means of an articulation element defining a steering axis around which the wheel upright is rotatably mounted.

[0009] Prior art

[0010] As it is known, the geometries of the various components forming a motor-vehicle wheel suspension assembly determine different physical and / or virtual axes characteristic of the suspension which influence the dynamic behavior of the vehicle.

[0011] For example, in MacPherson architecture suspensions, the steering axis is identified by an axis passing through the center of a spherical head constrained to a lower oscillating arm, and through the center of the upper block of the shock absorber assembly.

[0012] In the case of a suspension with quadrilateral architecture, the steering axis is determined by an axis passing through two spherical heads, respectively constrained to a lower arm and an upper arm.

[0013] However, such suspensions are not without some drawbacks, comprising the high complexity of the wheel assembly to advantageously determine said characteristic axes, and the high sensitivity to accidental events during vehicle dynamics which could affect the full functionality of the suspension assembly.

[0014] Object of the invention

[0015] The object of the present invention is to provide a suspension of the type indicated above which is particularly efficient, compact, and which is less sensitive to accidental events which could affect optimal vehicle dynamics.

[0016] A further object of the invention is to provide a suspension of the type indicated above which comprises an articulation group defining a steering axis which can be applied to different archetypes of vehicle suspension.

[0017] A further object of the invention is to provide a suspension of the type indicated above designed to vary the motor-vehicle ground clearance using a simple and effective solution.

[0018] Summary of the invention

[0019] According to the invention, one or more of said objects are achieved thanks to a suspension having the features indicated in the attached claims.

[0020] Thanks to these features, it is possible to achieve a series of important advantages compared to the prior art, comprising:

[0021] - reducing the number of components to determine the steering axis;

[0022] - reducing the related production costs;

[0023] - simplifying the assembly system of the suspension unit;

[0024] - providing a modular solution applicable to different suspension archetypes;

[0025] - simplifying the packaging and / or the geometry of the suspension;

[0026] - obtaining different variations in vehicle ground clearance.

[0027] Brief description of the drawings

[0028] The invention will now be described in detail with reference to the attached drawings, provided purely by way of non-limiting example, in which:

[0029] - figure 1 is a perspective view of a suspension of a motor-vehicle steering wheel, according to a first embodiment of the invention,

[0030] - figure 2 is an enlarged scale view, in partial cross-section, illustrating some features of the previous figure,

[0031] - figure 3 is a further perspective view, on an enlarged scale, showing some features of the previous figure,

[0032] - figure 4 is a perspective view of a suspension of a motor-vehicle steering wheel, according to a further embodiment of the invention, and

[0033] - figure 5 is an enlarged scale view, in cross-section, illustrating some features of the previous figure. Detailed description of the invention

[0034] The following description illustrates various specific details aimed at an in-depth understanding of examples of one or more embodiments. The embodiments can be provided without one or more of the specific details, or with other methods, components, materials, etc.

[0035] In other cases, known structures, materials or operations are not shown or described in detail to avoid obscuring various aspects of the embodiments.

[0036] The reference to “an / one embodiment” in this description is to indicate that a particular configuration, structure or feature described in connection with the embodiment is included in at least one embodiment.

[0037] Therefore, phrases such as “in an / one embodiment”, possibly present in different places in this description, do not necessarily refer to the same embodiment. Furthermore, particular conformations, structures or features can be combined appropriately in one or more embodiments and / or associated with the embodiments in a different way from as illustrated here, so for example a feature exemplified here in relation to a figure it may be applied to one or more embodiments exemplified in a different figure.

[0038] The references illustrated here are for convenience only and therefore do not delimit the extent of protection or the scope of the embodiments.

[0039] The suspension according to the invention comprises a wheel upright 1 which rotatably supports a pin 2 of a motor-vehicle wheel. The suspension also comprises an oscillating arm 3 connectable to a motor-vehicle frame portion (not shown).

[0040] In the illustrated embodiment, the oscillating arm 3 is a driven longitudinal arm having two inner ends 4, 5, which can be pivotally connected to a portion of the motor-vehicle chassis by means of respective elastic elements (not shown).

[0041] The oscillating arm 3 comprises an outer end portion 6 comprising an articulation seat 8 of substantially cylindrical shape arranged to receive an articulation element 7 pivotally connected to the wheel upright 1. As described in detail below, the articulation element 7 defines a steering axis - indicated with the reference X in figure 1 - around which the wheel upright 1 is rotatably mounted

[0042] As illustrated in figure 2, the articulation element 7 comprises a substantially cylindrical central body 7’ engaged within the articulation seat 8, and end portions 9, 10, opposite to the central body 7’, protruding above and below from the articulation seat 8 and connected to respective portions T, 1” of the wheel upright 1. According to an important feature described below, the suspension further comprises an electric actuator 11 operatively connected to a rack and pinion system 12 comprising a rack 14 directly formed along said central body 7’, configured for sliding the articulation element 7 along the axial direction.

[0043] In one or more embodiments, as illustrated in figure 1 , the articulation seat 8 is integrated into the oscillating arm 3 at one of its distal ends with respect to the inner ends 4, 5. Alternatively, the articulation seat 8 can also be formed by a connecting component suitably assembled at one end of the oscillating arm 3.

[0044] According to the embodiment illustrated in figure 1 , the oscillating arm 3 is made in a single piece through the mutual assembly of two arm portions, in particular a first arm portion 3’ comprising said two inner ends 4, 5 and a second arm portion 3” comprising said articulation seat 8. Note that the first and second portions 3’, 3” are mutually assembled along a respective longitudinal section, so as to form, in the final configuration, a single oscillating arm body, having an articulation seat 8 directly integrated without the aid of other support components interposed between the oscillating arm 3 and the articulation seat 8.

[0045] In one or more embodiments, the first and second arm portions 3’, 3” are rigidly connected to each other by gluing and / or screwing and / or riveting and / or welding and / or by interference.

[0046] In one or more embodiments, the terminal end of the first arm portion 3’ is coaxially mounted within a corresponding terminal end of the second arm portion 3”, or vice versa.

[0047] In other embodiments, the first and second arm portions 3’, 3” are directly formed in a single piece using additive manufacturing technology.

[0048] As indicated above, the articulation element 7 comprises a substantially cylindrical central body 7’, engaged within the articulation seat 8. The articulation element 7 also comprises opposite ends 9, 10 protruding from the articulation seat 8, connected respectively to an upper portion 1 ’ and a lower portion 1” of the wheel upright 1 . According to a further feature, the opposite ends 9, 10 are axially engaged within respective centering elements 9’, 10’ carried by the upper and lower portions 1 ’, 1” of the wheel upright 1. The centering elements 9’, 10’ can be made in the form of bearings, bushes or bushings rigidly engaged within respective holes obtained on the upper and lower portions 1 ’, 1”.

[0049] According to the configuration described above, the steering axis X of the suspension according to the invention is defined by the substantially cylindrical articulation element 7 engaged within the articulation seat 8.

[0050] In one or more embodiments, the suspension also comprises a cylindrical element made of material with a low friction coefficient placed between the articulation element 7 and the inner surface of the cylindrical articulation seat 8, in order to reduce mutual friction. The cylindrical element can advantageously be made in the form of a bush made of elastomer material or an axial needle bearing.

[0051] In view of the previous description, it will therefore be appreciated that the suspension according to the invention is particularly advantageous since the steering axis X is defined by a single component, i.e. the central cylindrical body 7’ of the articulation element 7 mounted within the articulation seat 8. The wheel upright 1 is therefore able to rotate around the X axis integrally with the rotation of the articulation element 7.

[0052] Furthermore, depending on the layout of the suspension, the loads it must overcome and the type of vehicle, this solution is “modular” as it is transversally applicable to different suspension archetypes, in accordance with one or more of the following modifications:

[0053] - varying the length and / or diameter of the central cylindrical body 7’ of the articulation element 7; and / or

[0054] - varying the length of arm 3 and / or rotating its end.

[0055] According to an important feature of the invention, the suspension further comprises an electric actuator 11 operatively connected to a rack and pinion system 12 configured for sliding the articulation element 7 along the axial direction, so as to modulate a vertical displacement of the wheel upright 1 and consequently vary the motor-vehicle ground clearance.

[0056] Observing the embodiment illustrated in figures 1 -3, the rack and pinion system 12 comprises a shaft 13 coaxial to said actuator 11 , oriented perpendicular to the articulation element 7. The shaft 13 comprises a plurality of contiguous projections and is meshed with a rack 14 directly formed along the central body 7’.

[0057] Observing the embodiment illustrated in figures 4, 5, the rack and pinion system 12 comprises a shaft 13 coaxial to said actuator 11 , oriented parallel to the articulation element 7. The shaft 13 comprises a plurality of contiguous projections and is meshed with a pinion 15 which in turn meshes with the rack 14 directly formed along the central body 7’ of the articulation element. In other words, the embodiment of figures 4, 5 presents the axis of the actuator spaced parallel to the axis of the central body 7.

[0058] In both embodiments, the rack and pinion system 12 transforms the rotary motion of the electric actuator 11 and the shaft 13 into linear motion of the articulation element 7.

[0059] Following the actuation of the actuator 11 , the articulation element 7 is configured for sliding along the axial direction inside the articulation seat 8, respectively downwards or upwards with reference to the final configuration installed on board the vehicle.

[0060] Advantageously, thanks to said features it is therefore possible to modulate the position of the upright 1 along said axial direction (which corresponds to the vertical direction with reference to an operating vehicle), thus varying the vehicle ground clearance to obtain benefits in aerodynamics or in overcoming any obstacles.

[0061] During operation, the user can actuate a specific control command to vary the motor-vehicle ground clearance in the manner described above. An electronic control unit can conveniently control the actuators 11 associated with each wheel upright of the vehicle, thus causing the wheel upright 1 to move upwards or downwards. Following the activation of the control command to return to the initial attitude, the actuator 11 is actuated in the opposite direction compared to the previous one.

[0062] Of course, notwithstanding the principle of the invention, the construction details and the embodiments may vary widely with respect to what is described and illustrated purely by way of example, without thereby departing from the scope of the present invention as defined in the attached claims.

Claims

CLAIMS1. Suspension of a motor-vehicle steering wheel, comprising:- a wheel upright (1 ),- a oscillating arm (3) connectable to a motor-vehicle frame portion,- wherein said oscillating arm (3) comprises an end portion (6) pivotally connected to the wheel upright (1 ) by means of an articulation element (7) defining a translation and steering axis (X) around which the wheel upright (1 ) is rotatably mounted,- wherein said articulation element (7) comprises a substantially cylindrical central body (7’) engaged within a substantially cylindrical articulation seat (8), and end portions (9,10) protruding from the articulation seat (8) and connected to respective portions (1 ’,1”) of said wheel upright (1 ),- wherein said steering axis (X) is defined only by the substantially cylindrical articulation element (7) engaged within said articulation seat (8),- said suspension further comprising an electric actuator (11 ) operatively connected to a rack and pinion system (12) comprising a rack (14) directly formed along said central body (7’), configured for sliding the articulation element (7) along the axial direction, so as to modulate a vertical displacement of the wheel upright (1 ) and consequently vary the motorvehicle ground clearance.

2. Suspension according to claim 1 , wherein said rack and pinion system (12) comprises a shaft (13) coaxial to said actuator (11 ) meshed with said rack (14) directly formed along said central body (7’).

3. Suspension according to claim 1 , wherein said rack and pinion system (12) comprises a shaft (13) coaxial to said actuator (11 ), oriented parallel to the articulation element (7) and meshed with a pinion (15) which is in turn meshed with said rack (14) directly formed along said central body (7’).

4. Suspension according to claim 1 , wherein said oscillating arm (3) is made in a single piece by mutual assembly of two arm portions (3’, 3”), along a respective longitudinal section.

5. Suspension according to claim 1 , wherein the oscillating arm (3) is directly formed in one piece by additive manufacturing technology.

6. Suspension according to claim 1 , wherein by keeping unchanged the wheel upright (1 ), the articulation seat (8) and the articulation element (7), and by varying the length of the arm (3) and / or rotating its end, said suspension results transversally applicable to different suspension archetypes according to the vehicle segment on which said suspension is installed.

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