Front wheel assembly for a vehicle with two front steering wheels and vehicle with said front wheel assembly

Abstract

To provide a tilting three-wheel vehicle that can simultaneously assure a user of the operability of a two-wheel vehicle and the stability and safety of a four-wheel vehicle. [Solution] A vehicle (1) has a front wheel assembly (2) and a pair of front steered wheels (3') connected to the front wheel assembly (2) by a tilting four-bar link (21). Each front steered wheel (3') is provided with a suspension four-bar link, which includes four components (23') hinged to one another about their respective articulation axes, and a shock absorber. The shock absorber is constrained to two components (23') of the suspension four-bar link. The articulation axes between the four components (23') of each suspension four-bar link are perpendicular to a plane containing the axes of the front wheels (3').

Description

[Technical Field]

[0001] The present invention relates to the field of tilting vehicles, i.e. vehicles that have a tilting movement about a central plane extending longitudinally along the vehicle. Tilting vehicles are typically three-wheeled vehicles with two front steering wheels and one rear driving wheel. The tilting movement allows the vehicle to lean during its operation, for example when negotiating a curve. [Background technology]

[0002] In the field of vehicles, there is an ever-increasing supply of vehicles that combine the ease of handling of a motorcycle with the stability of a four-wheeled vehicle.

[0003] These models include, for example, three-wheeled vehicles with two front steering wheels and one rear drive wheel, and four-wheeled vehicles, usually called quad bikes (buggys).

[0004] More specifically, the three-wheeled vehicles described above roll or lean laterally while rocking or leaning about an axis oriented substantially in the direction of travel, and include an engine coupled to rear drive wheels that provides torque to the rear drive wheels for traction while a pair of front wheels control the direction of the vehicle.

[0005] With this solution, a vehicle with two front drive wheels has greater stability than a two-wheeled vehicle due to the double support of the front wheels on the ground, similar to an automobile.

[0006] The front wheels are kinematically linked to each other using a mechanism that can substantially synchronize the tilt and steering of the front wheels, for example, by interposing a four-bar link that connects the front wheels to the front wheel frame. These vehicles also have two independent suspensions, one for each front wheel. Each suspension has an elastic body (spring) and a viscous body (shock absorber).

[0007] Therefore, the purpose of the tilting three-wheel vehicle is to simultaneously assure the user of the operability of a two-wheel vehicle and the stability and safety of a four-wheel vehicle.

[0008] This type of tilting three-wheel vehicle is disclosed, for example, in International Publication WO2017 / 115294, International Publication WO2017 / 115295, International Publication WO2017 / 115296, International Publication WO2017 / 115297, and International Publication WO2018 / 104906.

[0009] The design of the suspension and steering systems of this type of vehicle is an important aspect, as they must provide driving comfort and safety.

[0010] Therefore, there is a need for continuing improvements in suspension and steering systems for leaning vehicles having two front steered wheels. Summary of the Invention

[0011] According to a first aspect, the present invention relates to a front wheel assembly for a vehicle, comprising a tilting four-bar linkage and two suspension units for two front wheels. The tilting four-bar linkage comprises a first crossbar, a second crossbar, a first upright portion, and a second upright portion, which are hinged to one another. The first and second crossbars extend transversely to the center plane of the vehicle, i.e., in the right-left direction. The first and second upright portions are hinged to the first and second crossbars at two points spaced apart from one another. The first and second crossbars are hinged at their respective intermediate points to a front wheel assembly frame or an element rigidly connected to the front wheel assembly frame, such as a steering sleeve.

[0012] Each suspension unit is associated with a respective upright. Each suspension unit comprises a wheel support for each front wheel of the vehicle. The wheel support defines an axis of rotation for each wheel. Each suspension unit further comprises a support arm rotatably connected to each upright for rotation about the steering axis.

[0013] Each suspension unit also includes a respective suspension four-bar link. In some embodiments, the support arm, or a portion thereof, is one element of the suspension four-bar link, and the wheel support is a second element of the suspension four-bar link.

[0014] In the embodiments disclosed herein, each suspension four-bar link also includes a pair of cranks connecting the wheel support and the support arm. Specifically, each four-bar link includes a first crank hingedly connected to the wheel support and the support arm, and a second crank hingedly connected to the wheel support and the support arm. The first crank, the second crank, the wheel support, and the support arm of each suspension unit are hingedly connected to each other to form a respective suspension four-bar link, and each suspension four-bar link essentially extends along a central plane substantially perpendicular to the central plane of each front steering wheel. In other words, the hinge axes through which the cranks are connected to the support arms and wheel support, i.e., the rotation axes of the parallel suspension four-bar link components, are perpendicular to a plane containing the rotation axes of each front steering wheel and parallel to the central plane of each front steering wheel.

[0015] Generally, the suspension four-bar link for each front steered wheel is perpendicular to the center plane of each front steered wheel, and each axis of interconnection between the two components of the suspension four-bar link is perpendicular to a plane containing the axis of rotation of each front steered wheel.

[0016] Each suspension unit further includes a shock absorber constrained at two points on the suspension four-bar link, the distance between which changes as the suspension four-bar link moves, such that as the four-bar link moves, for example due to up and down movement of each front steered wheel, the length of the shock absorber changes accordingly.

[0017] This type of front wheel assembly allows the contact point between the ground and the wheel, in projection on the vehicle's center plane, to move in a linear motion relative to the vehicle, rather than a rotational-translational motion, as occurs, for example, in the suspension systems disclosed in the following documents: International Publication WO2018 / 104906 discloses that the suspension four-bar link of each steering wheel is parallel to the center plane of the wheel and therefore has a hinge axis parallel to the rotation axis of each front steering wheel. The resulting suspension performs equivalently to a fork suspension but with significantly reduced costs and added kinematic advantages. While fork suspensions require mutually movable elements between which sliding supports, i.e., translational supports, are located, in the suspension four-bar link described herein, the up-and-down movement of the wheel causes the suspension four-bar link components to rotate about rotational supports rather than translational supports. This results in a system with low friction, adapted to provide better driving comfort, reduced wear, and reduced production and maintenance costs.

[0018] Additionally, in some embodiments, the above-described front wheel assembly has additional advantages over prior art configurations: in particular, the suspension four-bar links extending perpendicular to the center plane of each front steering wheel allow the camber angle of each front steering wheel to be controlled, and the camber angle can be changed during suspension compression, i.e., shock absorber compression, as occurs in high performance and racing cars.

[0019] Furthermore, the suspension four-bar link disclosed in this specification ensures that during rotation of the steering wheel about each steering axis, the plane in which the four-bar link lies and the plane in which the wheel lies are always oriented 90° relative to the steering axis.

[0020] According to another embodiment, the present invention relates to a motor vehicle comprising at least one rear drive wheel, two front steering wheels and a front wheel section as described above, wherein two wheel supports support the two steering wheels of the vehicle.

[0021] Also disclosed is a vehicle having a front axle and a pair of front steered wheels connected to the front axle using a tilting four-bar link. The vehicle further includes a suspension four-bar link and a shock absorber for each front steered wheel. Each shock absorber is constrained at two points to two components of the suspension four-bar link so that the shock absorber changes length as the suspension four-bar link moves. Each suspension four-bar link extends along a plane perpendicular to the plane in which each front steered wheel lies. In practice, each axis of mutual articulation between the two components of the suspension four-bar link is perpendicular to a plane containing the rotation axis of each front steered wheel.

[0022] Advantageously, the wheel support arm, one of the four elements of each suspension four-bar link, can form an upright extending toward the tilting four-bar link. In this way, the support arm of each front steering wheel kinematically connects said wheel to the four-bar link, and advantageously, the tilting four-bar link can be positioned at a higher level than the two suspension four-bar links. In this way, the suspension members in the area between the two front steering wheels are less bulky than, for example, those disclosed in International Publication WO2018 / 104906. This allows the two front wheels to be positioned closer together, i.e., closer to the center plane of the vehicle, since there is no need to leave space for the tilting four-bar link between the front wheels.

[0023] In a possible embodiment of the front wheel section and vehicle according to the invention, the shock absorber is interposed between the support arm and the wheel support.

[0024] For example, the wheel support may have a body to which the first crank and the second crank are joined at two spaced apart points, and the body may have appendages extending beyond the hinge points of the first crank and the hinge points of the second crank to which the shock absorbers are joined.

[0025] In other embodiments of the front wheel assembly and / or vehicle described above, the shock absorber can be interposed between the support arm and an auxiliary rocker that is connected at two points to the first and second cranks. The auxiliary rocker can be advantageously located at an intermediate position between the wheel support and the support arm. This arrangement allows the shock absorber load to be distributed to both cranks. Furthermore, the constraint point between the shock absorber and the auxiliary rocker moves on a different trajectory than it would if the shock absorber were directly constrained to one of the cranks of the suspension four-bar link. In this way, the shock absorber can be positioned more freely depending on the mechanical dimensions of the various suspension components, and a sufficiently wide stroke of the shock absorber can be obtained during the up and down movement of each wheel.

[0026] Each support arm of the two front steering wheels may have a connection element for connecting to the steering system, for example, connecting the two support arms to a steering rod connected to a steering tube rotatably housed in a steering sleeve integrally formed in the front wheel frame.

[0027] For a particularly compact arrangement, the front wheel section may have tilting four-bar uprights adapted to form respective housings for rotatably receiving respective support arms of each suspension unit. The present invention will be better understood in accordance with the following description and the accompanying drawings which set forth illustrative and non-limiting embodiments of the invention. [Brief explanation of the drawings]

[0028] [Figure 1] 1 is a side view of a three-wheeled vehicle according to the present invention; [Figure 2] FIG. 2 is a plan view taken along line II-II in FIG. [Figure 3] FIG. 3 is a front view taken along line III-III in FIGS. 1 and 2. [Figure 4] FIG. 4 is a perspective view of the front of the vehicle shown in FIGS. 1, 2 and 3. [Figure 5A] FIG. 2 is an enlarged partial cutaway front view of one embodiment of a front wheel suspension. [Figure 5B] FIG. 2 is an enlarged partial cutaway front view of one embodiment of a front wheel suspension. [Figure 6A] FIG. 10 is an enlarged partial cutaway front view of another embodiment of the front wheel suspension. [Figure 6B] FIG. 10 is an enlarged partial cutaway front view of another embodiment of the front wheel suspension. [Figure 7] FIG. 7 is a view taken along line VII-VII in FIG. 6A. [Figure 8] FIG. 8 is a front view taken along line VIII-VIII in FIG. 7. [Figure 9] 5A and 6A, of yet another embodiment of a suspension unit; FIG. [Figure 10] FIG. 10 is a view taken along line XX in FIG. 9. [Figure 11] FIG. 11 is a view taken along the line XI-XI in FIG. [Figure 12] FIG. 1 is a kinematic diagram of an embodiment of a front wheel of a vehicle. [Figure 13] FIG. 10 is a kinematic diagram of another embodiment of a front wheel of a vehicle. DETAILED DESCRIPTION OF THE INVENTION

[0029] Although the accompanying drawings show an embodiment of the present invention applied to a three-wheeled vehicle, i.e., a vehicle having one rear drive wheel, as mentioned above, the front wheel portion of the present invention can also be applied to four-wheeled vehicles such as so-called quad bikes.

[0030] To better understand the novel features of the various embodiments of the suspension and steering system according to the present invention, FIGS. 1 to 11 show practical embodiments thereof, while FIGS. 12 and 13 show kinematic diagrams of the components defining the suspension and the members enabling the vehicle's tilting and front wheel steering movements.

[0031] The vehicle 1 has a front wheel section or front axle section, designated by the reference number 2, to which two front steered wheels 3' and 3" are associated. In the following description, components, groups or elements that are symmetrical with respect to a central plane M of the vehicle 1 are designated by the same reference number, with a comma (') following the reference number for elements on one side of the central plane M, e.g. elements on the left side of the driver, and a comma ('') following the reference number for elements on the other side of the central plane M, e.g. elements on the right side of the driver. When a reference number in which commas ('') and (') are used to denote elements on the right and left side of the central plane, respectively, is used without the comma, it means that reference may be made to either the right or left element without distinction.

[0032] The vehicle 1 also includes an engine 5 and rear drive wheels 7 equipped with a transmission member, the details of which are not shown.

[0033] The front wheel section 2 includes a front wheel section frame 9, and a steering sleeve 11 is integrally provided with the front wheel section 9. A steering tube 13 is rotatably housed within the steering sleeve 11 and is torsionally connected to a handlebar 15. As shown in the kinematic diagrams of Figures 12 and 13, the driver applies steering to the front steering wheels 3', 3'' via the handlebar 15.

[0034] As will be explained in more detail below, the front wheel section 2 of the vehicle 1 includes a tilting four-bar link 21 to which the wheels 3', 3" are connected. The tilting four-bar link allows the vehicle to lean when negotiating a curve. Each wheel 3', 3" is connected to the tilting four-bar link 21 by a respective support arm 23', 23", which is part of a respective suspension four-bar link 25', 25". Each suspension four-bar link 25', 25" includes a shock absorber 26', 26". Each suspension four-bar link 25', 25" with its respective shock absorber 26', 26" is part of a suspension unit for the wheel 3', 3", generally designated 28', 28". Each suspension unit 28', 28" is connected to the tilting four-bar link 21 via a respective support arm 23', 23", which constitutes an upright extension of one of the elements of the suspension four-bar link 25', 25".

[0035] Each support arm 23', 23" is connected to the tilting four-bar linkage 21 so as to be rotatable about and relative to a respective steering axis 27', 27" controlled by the handlebar 15. For this purpose, each support arm 23', 23" is provided with a connecting member 24', 24" for connecting it to a steering bar 29 which is part of the steering link connecting the support arm 23', 23" to the steering tube 13.

[0036] More specifically, the tilting four-bar linkage 21 comprises a first crossbar 31 (upper crossbar) and a second crossbar 33 (lower crossbar). Each crossbar 31, 33 is joined to the front wheel frame 9, more precisely to the steering sleeve 11 in the illustrated example, at a central point indicated by reference numeral 31A for the crossbar 31 and reference numeral 33A for the crossbar 33. In this way, the crossbars 31 and 33 can rotate about a tilt axis defined by the hinges connecting the crossbars to the front wheel frame. As shown in Figure 3, when the tilt angle of the vehicle 1 is equal to zero, the tilt axes are substantially parallel to each other and lie on the central plane M of the vehicle 1.

[0037] The inclined four-bar link 21 also has two upright portions 35' and 35''. More specifically, the upper crossbar 31 is joined to the upright portion 35' at the position indicated by reference numeral 32' and to the upright portion 35'' at the position indicated by reference numeral 32''. The lower crossbar 33 is joined to the upright portion 35' at the position indicated by reference numeral 34' and to the upright portion 35'' at the position indicated by reference numeral 34''. In FIG. 7, reference numerals 32X and 34X indicate the axes of the joints connecting the upright portion 35 and the crossbars 31, 33.

[0038] In the illustrated embodiment, the uprights 35', 35" are shaped like cylindrical housings within which the upper part of each support arm 23', 23" is supported. Rotational bearings or bushings, not shown, allow the support arms 23', 23" to rotate within the housing formed by each upright 35', 35".

[0039] Each support arm 23', 23" extends downward from the tilting four-bar link 21, and a respective suspension four-bar link 25', 25" is formed thereon. Therefore, the tilting four-bar link 21 is disposed at a higher position than the two suspension four-bar links 25', 25" and each wheel 3', 3".

[0040] Each suspension four-bar link 25', 25" is formed by four elements, one of which is a corresponding support arm 23', 23", which actually constitutes the rocker of the suspension four-bar link 25', 25", extending upright upwards towards the inclined four-bar link. A wheel support 41', 41" is connected to each of the two support arms 23', 23".

[0041] Each wheel support 41', 41'' defines a rotation axis 43', 43'' for each wheel 3', 3''. Reference numerals 45', 45'' designate the rotation axis of each wheel 3', 3'' (see in particular Figures 5A, 5B; 6A, 6B).

[0042] Each wheel support 41', 41" is connected to a respective support arm 23', 23" by a pair of cranks 42A', 42B' and 42A", 42B". Reference numerals 47A', 47B' indicate the articulation hinges of the cranks 42A', 42B' to the support arm 23', and reference numerals 47A", 47B" indicate the articulation hinges of the cranks 42A", 42B" to the support arm 23". In Figure 7, reference numerals 47X and 47Y indicate the axes of rotation of the articulation hinges 47A" and 47B" of the cranks 42A", 42B" to the support 23". Similarly, reference numerals 48A', 48B' designate the articulation hinges of the cranks 42A', 42B' to the wheel support 41', and reference numerals 48A'', 48B'' designate the articulation hinges of the cranks 42A'', 42B'' to the wheel support 41''. The axes of the articulation hinges 47A, 47B, 48A and 48B of the four elements 23, 41, 42A and 42B of each suspension four-bar link 25 are parallel to one another and perpendicular to the plane containing the rotation axes 43', 43'' of the wheels 3', 3''.

[0043] Each suspension four-bar link 25', 25" extends along a plane parallel to the rotation axis 43', 43" of the respective wheel. Therefore, the plane in which each suspension four-bar link 25', 25" lies is perpendicular to the plane in which each front steering wheel 3', 3" lies. In this specification, the term "plane in which one or more members lies" means a central plane passing through the elements of the member. Therefore, in the case of a four-bar link such as the suspension four-bar link 25', 25", the plane in which the four-bar link lies is the central plane of the cranks 42A, 42B, and of the portion of the wheel support 41 and the portion of the suspension arm 23 to which the cranks 42A, 42B are joined. Note that in the simplified kinematic diagrams of Figures 12 and 13, the plane in which the simplified suspension four-bar link 25 lies substantially coincides with the plane of the drawing, and the plane in which the wheel 3 lies is a plane perpendicular to the plane of the drawing. In this embodiment, the plane on which the suspension four-bar link 25 lies is inclined rearward, for example, by about 10°, with respect to the vertical, as shown in Figure 7. The center plane of the suspension four-bar link 25 or the plane on which it lies is indicated by the symbol M25 in Figure 7.

[0044] The plane in which the wheels 3 lie is the same wheel centre plane, designated 3A' and 3A'' as can be seen with particular reference to Figures 5A, 5B and 6A, 6B.

[0045] Each suspension four-bar link 25', 25'' is essentially positioned so that its center plane, i.e., the plane in which the four-bar link 25', 25'' lies as described above, is substantially perpendicular to the plane in which each front wheel 3', 3'' lies.

[0046] In a practical embodiment, for greater mechanical strength, each crank 42A', 42A'', 42B' and 42B'' can be doubled, as can be seen in Figure 3 and in particular in Figure 7. In Figures 5A, 5B and 6A, 6B, only one component of each double crank is shown, more precisely, the component located behind the shock absorber 26', 26'' in each figure, the corresponding component located in front of the shock absorber 26', 26'' being omitted to better show the layout of the shock absorber 26', 26''. In other embodiments, each crank can be U-shaped or H-shaped, i.e., double, but made of a single piece rather than consisting of two components hinged on a common axis.

[0047] Each wheel support 41', 41'' may be adapted to support the axis of rotation 45', 45'' of each wheel 3', 3'', as well as a brake unit 51', 51'' acting on a brake disc 53', 53''.

[0048] Each shock absorber 26', 26" may generally include a resilient element, such as a helical spring 61', 61", and a damping element 63', 63". In the illustrated embodiment, each resilient element 61 and each damping element 63 are arranged coaxially with each other, but this is not required. For example, the damping element and the resilient element may be arranged parallel to and adjacent to each other.

[0049] Suitably, each shock absorber 26', 26" is constrained, preferably at its ends, directly or indirectly to two different points on each suspension four-bar link 25', 25". More precisely, to allow correct operation of the suspension four-bar link 25', 25" and the corresponding shock absorber 26', 26" the shock absorbers 26', 26" are constrained at two points whose mutual distance changes as each four-bar link deforms due to up and down movement of the wheels. In the embodiment of Figures 1, 2, 3, 4, 6A, 6B, 7, 8 and 12, each shock absorber 26', 26'' is hinged at its top, at point 26A', 26A'', to the support arm 23', 23'' and at its bottom, at point 26B', 26B'', to an appendage or extension 41A', 41A'' extending from the body of the corresponding wheel support 41', 41'' to which the cranks 42A', 42B' and 42A'', 42B'' are joined.

[0050] When the four-bar links 25', 25'' deform, the two hinge points 26A', 26B'; 26A'', 26B'' of each shock absorber 26', 26'' move toward or away from each other (resulting in the shock absorber becoming shorter or longer).

[0051] The above-described method of restraint between the shock absorbers 26 and the elements of the suspension four-bar link 25', 25" is not the only one possible. In the embodiment of Figures 5A, 5B, and 13, each shock absorber 26 is hinged at 26A', 26A" to a corresponding support arm 23', 23", substantially similar to the embodiment of Figures 1 to 4, 6A, 6B, 7, 8, and 12, but at the bottom, each shock absorber 26', 26" is hinged at 26B', 26B" to an auxiliary rocker 71', 71" having an attachment 71A', 71A" which in turn is hinged to the cranks 42A', 42B' and 42A", 42B", respectively. Preferably, the auxiliary rockers 71', 71'' (see especially Figures 5A and 5B) are located at intermediate positions between the wheel supports 41', 41'' and the support arms 23', 23''.

[0052] In a particularly advantageous embodiment, as shown in the accompanying drawings, each support arm 23', 23" has a lower curved portion that is displaced towards the centre line of the vehicle 1 relative to the corresponding steering axis 27', 27" so as to have more space for mounting the shock absorbers 26', 26" while maintaining a reduced distance between the two front steering wheels 3', 3". The two support arms 23', 23" are spread apart upwards and are connected to uprights 35', 35" of the tilting four-bar link 21.

[0053] 9, 10 and 11 show a third embodiment of the right suspension unit 28''. The same reference numerals designate elements that are the same as or equivalent to those shown and described in the previous figures. These elements will not be described again. FIG. 9, like FIG. 5A, is a partial cross-sectional view taken along a substantially vertical plane parallel to the plane of extension of the suspension four-bar link 25''; i.e., the plane in which the suspension four-bar link 25'' lies. FIG. 10 is a side view of the vehicle 1 taken along arrow XX in FIG. 9, i.e., essentially from the center plane MM of the vehicle 1, and FIG. 11 is a front view of the suspension unit 28'' taken along line XI-XI in FIG. 10.

[0054] The embodiment of Figures 9-11 includes an auxiliary rocker 71'', making it kinematically equivalent to the embodiment of Figures 5A, 5B, and 13. The bottom of the shock absorber 26'' is articulated relative to the auxiliary rocker 71'' at a location designated 71A''. The embodiment of Figures 9, 10, and 11 differs from the embodiment of Figures 5A and 5B in that the auxiliary rocker 71'' is shaped differently, so that it does not protrude below the suspension four-bar link 25''. More specifically, the rocker 71'' is completely contained within the volume defined by the cranks 42A'', 42B''. This allows the shock absorber 26'' to be positioned farther from the ground and its lower end to be hidden, resulting in aesthetic and functional benefits.

[0055] Furthermore, in the embodiment of Figures 1 to 8, the hinge axes 32X and 34X are parallel to each other and to the hinge axes 47X and 47Y (see particularly Figure 7), but in the embodiment of Figures 9 to 11, as can be seen particularly in Figure 10, the axes 47X and 47Y are not parallel to the axes 32X and 34X but are inclined thereto, for example, by approximately 5°.

Claims

1. A front wheel assembly (2) for a vehicle, an inclined four-bar link (21) having a first crossbar (31), a second crossbar (23), a first upright portion (35') and a second upright portion (35'') that are hingedly connected to each other; a respective suspension unit (28', 28'') associated with each upright (35', 35''); Equipped with The suspension unit is a wheel support (41', 41'') for a wheel (3', 3'') of a vehicle, the wheel support (41', 41'') defining an axis of rotation (43', 43'') of the wheel (3', 3''); a support arm (23', 23'') rotatably connected to each upright (35', 35'') for rotation about a steering axis (27', 27''); A first crank (42A', 42A'') is connected to the wheel support (41', 41'') and the support arm (23', 23'') via respective first articulation axes (47A', 48A'; 47A'', 48A''), and a second crank (42B', 42B') is connected to the wheel support (41', 41'') and the support arm (23', 23'') via respective second articulation axes (47A', 48A'; 47A'', 48A''). 42B″), wherein the first crank (42A′, 42A″), the second crank (42B′, 42B″), the wheel support (41′, 41″) and the support arm (23′, 23″) form a suspension four-bar link (25′, 25″), and the first and second cranks have angular first and second joint axes perpendicular to a plane containing the rotation axes (43′, 43″) of the wheels (3′, 3″); a shock absorber (26', 26'') that is constrained at two points (26A', 26A''; 26B', 26B'') of a suspension four-bar link (25', 25''), and the distance between the two points is changed when the suspension four-bar link (25', 25'') moves and the length of the shock absorber changes; A front wheel portion for a vehicle, comprising:

2. The shock absorbers (26', 26'') are connected to the support arms (23', 23'') and the wheel supports (41', 41''). The front wheel assembly according to claim 1 .

3. the wheel support portion (41', 41'') has a body to which the first crank (42A', 42A'') and the second crank (42B', 42B'') are joined at two points spaced apart from each other; The body extends beyond the articulation point of the first crank and the articulation point of the second crank with appendages (41A', 41A'') to which shock absorbers (26', 26'') are attached. The front wheel section according to claim 2 .

4. The shock absorbers (26', 26'') are connected to the auxiliary rockers (71', 71'') and support arms (23', 23'') which are joined at two points to the first cranks (42A', 42A'') and the second cranks (42B', 42B''). The front wheel assembly according to claim 1 .

5. The auxiliary rockers (71', 71'') are disposed at intermediate positions between the wheel supports (41', 41'') and the support arms (23', 23''). The front wheel assembly according to claim 4 .

6. The wheel supports (41', 41'') support the brake units (51', 51''). A front wheel portion according to any one of claims 1 to 5.

7. The support arms (23', 23'') are provided with connecting members (24', 24'') for connecting to a steering system. A front wheel portion according to any one of claims 1 to 6.

8. The shock absorber (26', 26'') comprises a damping element (63', 63'') and an elastic element (61', 61''), in particular a helical spring. A front wheel section according to any one of claims 1 to 7.

9. The damping element (63', 63'') and the elastic element (6, 61'') are arranged around a common axis or around two substantially parallel axes. The front wheel assembly according to claim 8 .

10. The two support arms (23', 23'') are connected together by a steering link (29) A front wheel section according to any one of claims 1 to 9.

11. The two upright portions (35', 35'') of the inclined four-bar link (21) each form a housing, and the support arms (23', 23'') of each suspension unit (28', 28'') are rotatably supported in each housing. A front wheel section according to any one of claims 1 to 10.

12. The tilting four-bar link (21) is positioned higher than the suspension four-bar links (25', 25''). A front wheel section according to any one of claims 1 to 11.

13. The vehicle comprises a front wheel frame (9) integrally formed with a steering sleeve (11), a steering post (13) rotatably housed within the steering sleeve (11), and the steering post (13) is constrained to two support arms (23', 23'') by a steering link (29). A front wheel section according to any one of claims 1 to 12.

14. At least one rear drive wheel (7); A front wheel part (2) according to any one of claims 1 to 13; a pair of front steering wheels (3', 3'') each supported by one of the wheel support portions (41', 41''); A vehicle characterized by having:

15. The vehicle, A front wheel portion (2), A pair of front steering wheels (3', 3'') connected to the front wheel section (2) by an inclined four-bar linkage (21); a suspension four-bar link (25', 25'') for each front steering wheel (3', 3''); Equipped with The suspension four-bar link (25', 25'') The vehicle has four components (23', 23"; 42A', 42A"; 42B', 42B"; 41', 41"); and shock absorbers (26', 26"); connected around respective articulation axes (47A', 47A", 48A', 48A", 47B', 47B", 48B', 48B"); The shock absorbers (26', 26'') are constrained to two components (23', 23''; 41', 41'') of the suspension four-bar links (25', 25'') so that the length of the shock absorbers (26', 26'') changes in response to movement of the suspension four-bar links (25', 25''). In the vehicle (1), The articulation axes (47A', 47A'', 48A', 48A'', 47B', 47B''; 48B', 48B'') between the four components (23', 23''; 42A', 42A''; 42B, 42B''; 41', 41'') of each suspension four-bar link (25', 25'') are perpendicular to a plane containing the rotation axes (43', 43'') of the respective front wheels (3', 3''). A vehicle characterized by:

16. Each suspension four-bar link (25', 25'') has an upright portion (23', 23'') extending toward the tilting four-bar link (21), and the tilting four-bar link is provided at a position higher than the front steering wheels (3', 3'').

16. The vehicle of claim 15.

17. The uprights (23', 23'') of each suspension four-bar link (25', 25'') are rotatably connected to the uprights (35', 35'') of the tilting four-bar link (21) so as to rotate about the respective steering axes (27', 27'').

17. The vehicle of claim 16.

18. The front wheel part (2) has the features of any one of claims 1 to 13.

18. A vehicle according to any one of claims 15 to 17.

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