Motor vehicle having a suspension using a Watt four-bar linkage

Abstract

The invention relates to a riding motor vehicle (1; 107; 207) comprising a rear drive wheel (5; 105; 205) and a front steering wheel (7; 107; 207). The front steering wheel (7; 107; 207X, 207Y) is connected to a rotatable arm (9; 109; 209X, 209Y) which provides a rotational movement around a steering axis (A-A). The wheel support (37; 137) is connected to the rotatable arm (9; 109; 209) through the intervention of a suspension (17; 117; 217X, 217Y) comprising a shock absorber (22; 122). The suspension (17; 117) comprises a Watt four-bar linkage.

Description

Technical Field

[0001] The present invention relates to improvements in riding vehicles having two, three or four wheels. More specifically, the present invention relates to improvements in the front suspension of riding motor vehicles of the tilting type having one or two rear drive wheels and one or two front steering wheels, such as two-wheeled or three-wheeled motorcycles, two-wheeled or three-wheeled scooters, quad bikes, etc. Background Art

[0002] A riding motor vehicle with two, three or four wheels usually has one or two rear drive wheels connected to the frame of the motor vehicle by means of its rear suspension and one or two front steering wheels connected to the handlebars and equipped with a corresponding front suspension. The suspension connects the sprung mass to the unsprung mass of the motor vehicle and allows relative movement between the sprung mass and the unsprung mass. The suspension is usually a shock-absorbing suspension and includes a corresponding shock absorber, which in turn includes an elastic member (usually a spring) and a brake or damper. The suspension also includes a mechanical member that connects the sprung mass to the unsprung mass while allowing relative movement between the sprung mass and the unsprung mass, so that the impact transmitted to the wheel by the roughness or unevenness of the ground is not transmitted to the frame of the vehicle or is transmitted to the frame of the vehicle in a damped manner.

[0003] In riding vehicles such as motorcycles, scooters, quad bikes, etc., the suspension of the front steered wheels allows relative movement between the handlebars and steering column on one side and one or more front steered wheels on the other side. The suspension of the front steered wheels of some riding motor vehicles uses telescopic forks, which have members that slide on each other to allow the above-mentioned relative movement. Telescopic forks use cylindrical pairs with members that slide on each other; therefore, these forks have some typical problems of this type of relative movement. Vice versa, other types of suspension use revolute pairs with members that rotate on each other. In this case, a four-bar linkage, typically a four-bar linkage, is inserted between the sprung mass and the unsprung mass and deforms to allow the spring movement between the sprung mass (the frame of the vehicle and the members connected to it) and the unsprung mass (wheels, brakes). The revolute pair is represented by a hinge that connects the parts of the four-bar linkage to each other.

[0004] Suspensions that connect the sprung and unsprung masses using a kinematic mechanism with a revolute pair have the advantages of a revolute pair over prismatic and cylindrical pairs, but do not allow linear motion of the axis of the front steering wheel. In fact, during the spring movement, when the suspension is compressed and extended (for example, due to uneven ground or during braking caused by dynamic forces generated on the frame and transmitted to the wheel through the suspension), the axis of the wheel performs non-linear motion, resulting in lateral frictional motion of the wheel on the ground, which can cause problems such as bouncing.

[0005] It would therefore be advantageous to provide a suspension for the front steered wheel of a saddle-type motor vehicle having two or more wheels which allows combining the advantages of a telescopic fork suspension with the advantages of a suspension using a kinematic mechanism having a revolute pair. Summary of the invention

[0006] According to one aspect, a riding motor vehicle having at least one rear drive wheel and at least one first front steering wheel is disclosed herein, the first front steering wheel being connected to a rotatable arm that provides rotational movement about a steering axis. A wheel support is connected to the rotatable arm through the intervention of a suspension that connects the wheel support and the wheel mounted thereon to the rotatable arm. The suspension includes a shock absorber. The wheel support supports the front steering wheel and defines the axis of rotation of the wheel. For example, a wheel mounting shaft may be fixed to the wheel support, or the wheel support may have a support bearing for the wheel axle. Typically, the suspension includes a Watt four-bar linkage, also referred to as a Watt mechanism.

[0007] In an advantageous embodiment, the wheel support is constrained to the connecting rod in such a way that the rotation axis of the wheel is parallel to the axes of the first and second hinges of the first crank and to the axes of the first and second hinges of the second crank.

[0008] In this case, the components of the Watt four-bar linkage move on corresponding planes that are orthogonal to the axis of rotation of the front steering wheel. By illustrating these elements as one-dimensional elements, they lie on a plane that is orthogonal to the axis of rotation of the front steering wheel.

[0009] In this case, the wheel support can be rigidly connected to the connecting rod and form a housing for the support bearing of the front steering wheel.

[0010] In order to obtain a particularly compact construction of the suspension, in some advantageous embodiments, the first hinge of the first crank and the second hinge of the second crank are located on a first side of a plane containing the axis of rotation of the front steering wheel and passing through the point of constraint of the shock absorber to the rotatable arm. Vice versa, the second hinge of the first crank and the first hinge of the second crank are located on a second side of said plane. In practice, the plane defined above divides the space into a first half-space, the first half-space containing the first hinge of the first crank and the second hinge of the second crank, and a second half-space containing the second hinge of the first crank and the first hinge of the second crank.

[0011] In practice, relative to the forward direction of the vehicle, the first hinge of the first crank and the second hinge of the second crank are in a rearward position, while the second hinge of the first crank and the first hinge of the second crank are in a forward position.

[0012] Alternatively, relative to the forward direction of the vehicle, the first hinge of the first crank and the second hinge of the second crank are in a forward position, and the second hinge of the first crank and the first hinge of the second crank are in a rearward position.

[0013] In other embodiments, the axes of the first hinge and the second hinge of the first crank and the axes of the first hinge and the second hinge of the second crank are substantially parallel to each other and orthogonal to a plane containing the rotation axis of the front steering wheel. In practice, in this case, the various elements of the Watt four-bar linkage move on corresponding planes parallel to the rotation axis of the front steering wheel, and the movement planes of the various components of the Watt four-bar linkage are parallel to each other.

[0014] In order to obtain a particularly compact construction of the Watt four-bar linkage in this case, in some embodiments, the first hinge of the first crank and the second hinge of the second crank can be located on a first side of a plane that is orthogonal to the axis of rotation of the front steering wheel and passes through the constraint point of the shock absorber to the rotatable arm; the second hinge of the first crank and the first hinge of the second crank can be located on a second side of the plane.

[0015] In practice, the first hinge of the first crank and the second hinge of the second crank are closer to the front steering wheel, while the second hinge of the first crank and the first hinge of the second crank are at a greater distance relative to the front steering wheel.

[0016] In some embodiments, the wheel support is hinged to the connecting rod about an axis substantially parallel to the axis of the first hinge and the second hinge of the first crank and the second crank. The arrangement of the hinges of the four-bar linkage relative to a plane parallel to the plane where the wheels are located and passing through the hinge axis between the wheel support and the connecting rod can be such that: the first hinge of the first crank and the second hinge of the second crank are located on one side of the plane, for example, in the half space defined by the plane where the front steering wheel is located; vice versa, the second hinge of the first crank and the first hinge of the second crank are located on the other side of the plane, i.e., in the half space defined thereby that does not contain the front steering wheel.

[0017] In a practical embodiment, the wheel support supports the wheel in such a position that the rotation axis of the wheel is orthogonal to the axis about which the wheel support is articulated to the connecting rod.

[0018] The motor vehicle may include a disc brake for the front steering wheel, the disc brake having a disc and a caliper integral with the front steering wheel, wherein the caliper is rigidly connected to the wheel support. In other embodiments, the caliper is rigidly connected to a support member mounted idling relative to the connecting rod and the wheel support.

[0019] According to another aspect, there is provided a riding motor vehicle having at least one rear drive wheel and at least one first front steered wheel, the first front steered wheel being connected by means of a suspension to a rotatable arm providing a rotational movement about a steering axis; wherein:

[0020] a wheel support for supporting the front steerable wheel and defining the axis of rotation of said wheel connected to the rotatable arm through the intervention of the suspension;

[0021] The suspension includes a four-bar linkage having a first crank and a second crank, wherein a first end of the first crank is hinged to the rotatable arm and a second end is hinged to the connecting rod, and a first end of the second crank is hinged to the rotatable arm and a second end is hinged to the connecting rod;

[0022] The wheel supports are constrained at the constraint points of the connecting rods; and

[0023] The four-bar linkage is configured such that during deformation of the four-bar linkage due to spring movement of the suspension, the constraint point travels along an approximately straight line trajectory. BRIEF DESCRIPTION OF THE DRAWINGS

[0024] The present invention will be better understood through the following description and accompanying drawings, which show non-limiting examples of embodiments of the present invention. More specifically, in the drawings:

[0025] Figure 1 shows an axonometric view with certain components removed of a two-wheeled motor vehicle having a front suspension according to one embodiment;

[0026] Figure 2 Shows Figure 1 a front view of a motor vehicle;

[0027] Figure 3 Shown according to Figure 2 Side view of III-III;

[0028] Figure 4A and 4B They are shown respectively Figures 1 to 3 An enlarged side view of the suspension in the extended and compressed positions;

[0029] Figure 4C Shows Figure 1 , 2 , 3, 4A, 4B's exploded view of the suspension;

[0030] Figure 4D A schematic diagram showing the suspension in three different positions is shown;

[0031] Figure 5 Shown according to Figure 4A Front view of line VV;

[0032] Figure 6 Shows Figure 4A , 4B and 5 's axonometric view of the suspension;

[0033] Figure 7Another embodiment of the front suspension is shown similar to Figure 4A Side view of

[0034] Figure 8 Shows Figure 7 Axonometric drawing of the suspension;

[0035] Fig. 9 Another embodiment of the front suspension is shown. Figure 7 Similar side view;

[0036] Fig.10 Shows Fig. 9 Axonometric drawing of the suspension;

[0037] Fig.11 Another embodiment of the front suspension is shown. Fig. 9 Similar side view;

[0038] Fig.12 Shows Fig.11 Axonometric drawing of the suspension;

[0039] Fig.13 Another embodiment of the front suspension is shown. Fig.11 Similar side view;

[0040] Fig.14 Shows Fig.13 Axonometric drawing of the suspension;

[0041] Fig.15 shows a side view of another embodiment of a front suspension;

[0042] Fig.16 shows a side view of yet another embodiment of a front suspension according to the present specification;

[0043] Fig.17 shows a side view of one embodiment of a front suspension in which the brake caliper is mounted freewheelingly relative to a Watt four-bar linkage;

[0044] Fig.18 Shows Fig.17 Axonometric drawing of the suspension;

[0045] Fig.19 Shows Fig.16 and 17 Exploded view of the suspension;

[0046] Fig. 20 The use of a suspension according to the invention on a motor vehicle in the form of a scooter is shown;

[0047] Fig.21 shows an axonometric view of a suspension according to the invention, in which the axes of rotation of the components of the Watt four-bar linkage are orthogonal to the axis of rotation of the front steering wheels;

[0048] Fig. 22 Shows Fig.21 Axonometric drawing of the suspension;

[0049] Fig.23 Shown according to Fig. 22 XXIII-XXIII side view;

[0050] Fig.24 Shows Fig.21 , 22 and the suspension of 23, which does not have a rotatable arm by which the suspension is connected to the front steering wheel;

[0051] Fig.25 Shows Fig.21 , 22 , 23 and 24 suspensions in which the Watt four-bar linkage is removed;

[0052] Fig.26 shows an axonometric view of a three-wheeled motor vehicle having a double Watt four-bar linkage suspension for the two front steered wheels;

[0053] Fig. 27 Shows Fig.26 a front view of the motor vehicle; and

[0054] Fig.28 Shown according to Fig. 27 Side view of XXVIII-XXVIII. DETAILED DESCRIPTION

[0055] Figure 1 , 2 , 3, 4A, 4B, 4C, 4D, 5 and 6 show a two-wheeled motor vehicle with a Watt four-bar linkage suspension (ie, including a Watt mechanism) in a first embodiment.

[0056] Figure 1 , 2 3 schematically show a motor vehicle 1. In these views, parts of the motor vehicle that are not essential for understanding the structure and operation of the suspension have been removed or omitted. The motor vehicle 1 comprises a frame 3, a rear drive wheel 5 and a front steered wheel 7. The wheels 5 and 7 are connected to the frame 3 by means of a suspension. The rear suspension connecting the drive wheel 5 to the frame is not shown and can be configured in any known manner. The front suspension connecting the front steered wheel 7 to the frame 3 will be described in detail below.

[0057] The front steerable wheel 7 is connected to a rotatable arm 9. The latter is rigidly connected to a steering column 11 which is rotatably housed in a steering tube 13 and is manipulated to rotate about a steering axis AA by means of a handlebar 15. Rotation of the rotatable arm 9 about the axis AA allows the vehicle 1 to be steered.

[0058] The front steering wheel 7 is connected to the rotatable arm 9 by means of a suspension, indicated as a whole by 17, which allows the frame 3, including the steering tube 13, as well as the steering column 11, the handlebars 15 and the rotatable arm 9 to perform a spring movement relative to the front steering wheel 7. The suspension 17 is a shock-absorbing suspension, comprising: a kinematic mechanism for the connection between the front steering wheel 7 and the rotatable arm 9; and a shock absorber. The latter in turn comprises an elastic element and a brake or damper. In the embodiment shown, the shock absorber is indicated by 22, the elastic element by 21 and the brake or damper by 19. The latter is coaxially housed in the elastic element 21 in the form of a helical spring.

[0059] The front steerable wheel 7 is supported by the suspension 17 to rotate about its rotation axis BB.

[0060] Reference numeral 23 denotes a disc of a front brake of the motor vehicle 1. The brake also comprises a caliper 25 which can be supported by the suspension 17 in the following manner.

[0061] The suspension 17 comprises components connected to each other by means of revolute joints, ie components that move relative to each other according to one degree of freedom represented by a rotational movement about the respective hinge axis. The suspension thus has no elements providing mutual translational movement.

[0062] Advantageously, the kinematic mechanism with the revolute pair connecting the front steering wheel 7 to the rotatable arm 9 comprises a Watt four-bar linkage or a Watt mechanism. The latter comprises, in addition to the rotatable arm 9, a first crank 31 and a second crank 33. The two cranks 31 and 33 are articulated to the rotatable arm 9 and to a connecting rod 35, which is also part of the Watt four-bar linkage.

[0063] More specifically, the first crank 31 is hinged to the rotatable arm 9 by means of a first hinge 31A and is hinged to the connecting rod 35 by means of a second hinge 31B. The second crank 33 is in turn hinged to the rotatable arm 9 by means of a first hinge 33A and is hinged to the connecting rod 35 by means of a second hinge 33B. The hinges 31A, 31B, 33A, 33B form a revolute pair of a Watt four-bar linkage.

[0064] The lengths of the cranks 31 and 33 are approximately the same and are shorter than the connecting rod 35. The length of the components 31, 33, 35 refers to the distance between the axes of the respective hinges. Thus, for example, the length of the first crank 31 is given by the distance between the axes of the hinges 31A and 31B, the length of the second crank 33 is given by the distance between the axes of the hinges 33A and 33B, and the length of the connecting rod 35 is given by the distance between the axes of the hinges 31B and 33B.

[0065] The wheel support indicated at 37 is constrained in a constraining point of the link 35 which is substantially equidistant between the axes of the hinges 31B and 33B. In practice, the wheel support 37 defines the axis of rotation BB of the wheel and maintains said axis in a position midway between the axes of the hinges 31B and 33B and orthogonal to the link 35. Figures 1 to 6 In the embodiment of the present invention, the caliper 25 of the disc brake 23, 25 is rigidly fixed to the wheel support 37, specifically at Figure 4C can be seen in the exploded view.

[0066] exist Figures 1 to 6 In the embodiment of the invention, the shock absorber 22 is also hinged to the connecting rod 35. More specifically, the shock absorber 22 is hinged at one end 22A to the rotatable arm 9 and at one end 22B to the connecting rod 35. The constraints between the shock absorber 22 and the rotating arm 9 on one side and the connecting rod 35 on the other side can be formed by a ball joint.

[0067] From the diagram showing the extended and compressed positions of the suspension 17 and the shock absorber 22 Figure 4A , 4B It can be easily understood that the deformation movement of the Watt four-bar linkage allows the front steering wheel 7 to perform spring movement, more specifically, by means of the pivotal movement of the cranks 31, 33 around the axes 31A, 33A (the cranks are hinged to the rotatable arm 9 by means of the axis), the rotational translational movement of the connecting rod 35 and the compression / extension of the shock absorber 22 corresponding to the pivotal movement, allowing the front steering wheel 7 to perform spring movement.

[0068] Due to the characteristics of the Watt four-bar linkage, the center of the connecting rod 35 located on the rotation axis BB of the front steering wheel 7 moves along a substantially straight line trajectory, at least within a certain pivoting movement angle of the cranks 31, 33. The elements forming the Watt four-bar linkage are mounted so that the trajectory of the rotation axis BB of the front steering wheel 7 is approximately straight line for the entire travel of the suspension 17 from the maximum extension position to the maximum compression position.

[0069] By observation Figure 4D This feature of the suspension configured in this way can be easily understood by looking at the schematic diagram of FIG. The suspension, rotatable arm 9 and front steering wheel 7 are schematically represented here. Figure 4D Three different positions of the suspension are shown: a neutral position (a), a fully compressed position (b) and a fully extended position (c). It can be seen that, due to the characteristics of the Watt four-bar linkage 9, 31, 33, 35, the center of the front steering wheel 7 coincides with the line of the rotation axis BB of the front steering wheel moves on a substantially straight trajectory TT.

[0070] In this context, "approximately straight", "substantially straight" or "substantially straight" refers to a trajectory that deviates from a completely straight trajectory by less than 2 mm and preferably less than 1 mm within the range of use of the suspension (i.e., any position of the Watt four-bar linkage during normal use of the motor vehicle).

[0071] Now return to the structural features of the first exemplary embodiment, as specifically described in Figure 4A , 4B As can be seen in the figure, the first hinge 31A for connecting the first crank 31 to the rotatable arm 9 and the second hinge 33B for connecting the second crank 33 to the connecting rod 35 are located on a first side of a plane PP containing the axis of rotation BB of the front steering wheel 7 and being substantially parallel to the trajectory of said axis of rotation BB in the movement of the spring. The second hinge 31B for connecting the first crank 31 to the connecting rod 35 and the first hinge 33A for connecting the second crank 33 to the rotatable arm 9 are located on the other side of said plane PP. In practice, the hinges 31A and 33B are in a rearward position (relative to the normal direction of travel of the motor vehicle 1 in forward travel) relative to the hinges 31B and 33A. According to a further definition criterion, the hinges 31A and 33B are located on one side (or more precisely behind) a plane that contains the axis of rotation BB of the front steering wheel 7 and passes through the upper connection point 22A of the shock absorber 22 to the rotatable arm 9, i.e. on one side of a plane that contains the axis of rotation BB of the front steering wheel 7 and along which this axis translates during the movement of the spring.

[0072] This particular arrangement of the components forming the Watt four-bar linkage makes it possible to produce a compact arrangement suitable for forming a kinematic mechanism for connecting sprung and unsprung masses in the suspension of the front steered wheel of a riding motor vehicle 1 such as a motorcycle or scooter.

[0073] refer to Figures 1 to 6 The described embodiments are susceptible to numerous modifications, which are described below with reference to Figures 7 to 20 Describe some of them.

[0074] Figure 7 and Figure 8 The side view and the axonometric view of the front steering wheel 7 with the associated suspension 17 and the rotatable arm 9 are shown in an embodiment which differs from the previously described embodiments, in particular with regard to the point of constraint of the shock absorber 22 to the kinematic mechanism of the suspension 17. More specifically, the shock absorber 22, including the brake or damper 19 and the spring 21, is still constrained to the connecting rod 35, but the constraint position is in its upwardly facing rather than downwardly facing area, i.e., it is located on the side of the connecting rod 35 facing the first crank 31, while Figures 1 to 6 In the embodiment, the restraining portion 22B is located on the side of the connecting rod 35 facing the second crank 33. Figures 1 to 6 The remaining parts denoted by the same reference numerals are substantially identical to those described above.

[0075] Fig. 9 and 10 Another embodiment is shown, similar to Figure 7 and 8 Embodiments of the present invention, wherein the same or equivalent parts are used as Figures 1 to 8 The same reference numerals used in the drawings are indicated. Fig. 9 , 10 Configuration and Figure 7 , 8 The configuration is basically symmetrical. Figure 7 , 8 In (as in Figures 1 to 6 The upper crank 31 is oriented such that the hinge 31A for connecting to the rotatable arm 9 is located at the rearward end of the crank 31, and the hinge 31B for connecting to the connecting rod 35 is located at the forward end of the crank 31; the lower crank 33 is oriented in the opposite direction, that is, the hinge 33A for connecting to the rotatable arm 9 is at the forward end, and the hinge 33B for connecting to the connecting rod 35 faces backward. Fig. 9 and 10 In the configuration of , the arrangement is reversed: the upper crank 31 has a first hinge 31A at the end facing forward and a second hinge 31B at the end facing rearward. The lower crank 33 has a hinge 33B facing forward at one end and a hinge 33A facing rearward at one end.

[0076] Fig.11 and 12 Shown with Figure 7 and 8 The same numbers represent the same or equivalent parts as above. Figures 1 to 10 and Fig.11 , 12 The main difference between the two is that in this case the lower end of the shock absorber 19 is constrained at the bottom at a point 22B on the axis of rotation BB of the front steering wheel 7. The resulting configuration is particularly compact. The suspension 17 with the shock absorber 22 and the rotatable arm 9 can be enclosed in a housing 41.

[0077] Fig.15 A side view of another embodiment is shown, wherein like numerals indicate the same or equivalent parts to those already described above. Fig.15 Examples and Figures 1 to 6 The embodiment of is substantially the same, the main difference being that the shock absorber 22 is connected at the bottom, in 22B, to a crank 33 instead of a connecting rod 35 .

[0078] Fig.16 Shown with Figures 1 to 6 The embodiment of is substantially the same as that of the embodiment of the invention, except that the shock absorber 22 is connected at the bottom by means of a hinge 22B at the axis of rotation BB of the front steering wheel 7 .

[0079] As mentioned above, specifically Figure 4C As can be seen in FIG, the caliper 25 of the disc brake 23, 25 can be rigidly constrained to the connecting rod 35. In this case, the caliper 25 rotates integrally with the connecting rod 35. This occurs in particular during braking. Depending on the position of the caliper 25 relative to the axis of rotation BB of the front steering wheel 7, this movement may have a non-negligible front nod or anti-nod effect, since the instantaneous center of rotation of the connecting rod is close to the contact point of the front steering wheel 7 with the ground. This instantaneous center of rotation is defined by the intersection of the extensions of the two straight line segments connecting the hinges 31A, 31B and 33A, 33B to each other, respectively. Such a front nod or anti-nod effect may be undesirable.

[0080] In order to prevent or reduce the front nodding or anti-nodding effect of the suspension during braking, in some embodiments the caliper 25 can be rigidly connected to a member mounted coaxially with the front steering wheel 7 and therefore connected to the link 35 but not integral with the link and with its instantaneous center of rotation at a greater distance.

[0081] This type of embodiment is Fig.17 , 18 In these figures, the same numerals represent the same Figures 1 to 6 The same or equivalent parts as those described above will not be described again. Fig.19 The support member is indicated by 45. It may have a hole for accommodating a bearing 47, into which the shaft 7A of the front steering wheel 7 or an extension of this shaft is inserted. The link 35 of the Watt four-bar linkage is also supported idlingly on the shaft 7A. The member 45 may be rigidly connected to one end 22B of the shock absorber 22. The interlocking constraint between the shock absorber 22 and the member 45 keeps the caliper 25 from rotating about the axis BB during braking. Since the link 35 and the support member 45 of the caliper 25 are idling relative to each other, the link 35 and the member 45 are able to rotate freely relative to each other about the axis of rotation BB. The front nodding or anti-nodding effect is very limited or negligible, because in this case the member rigidly connected to the caliper consists of the shock absorber 22, whose instantaneous center of rotation is located at a large distance, almost infinitely far away.

[0082] The above suspension can be used for riding motor vehicles in the form of motorcycles, such as Figure 1 , 2 3, but may also be applicable to other types of riding motor vehicles. Fig. 20Purely by way of example, a scooter, again indicated at 1 , is shown having a Watt four-bar linkage suspension for the front steerable wheel 7 configured as described above.

[0083] exist Figures 1 to 20 In all the embodiments shown, the hinges connecting the cranks 31, 33 to the connecting rods 35 and the rotatable arm 9 are arranged with their hinge axes parallel to each other and to the axis of rotation BB of the front steered wheel 7. In this way, the Watt's four-bar linkage formed by the components 9, 31, 33, 35 lies substantially in a plane orthogonal to the axis of rotation BB of the front steered wheel 7. The axis of rotation of the revolute pair of the Watt's four-bar linkage is therefore oriented in the left-right direction, i.e. transversely to the median plane of the motor vehicle 1.

[0084] Although this produces a particularly efficient suspension, it is not the only possible embodiment of a four-bar linkage suspension, which enables the axis of rotation of the front steering wheel 7 to obtain a substantially straight-line trajectory during the sprung movement of the front steering wheel, using a kinematic mechanism having only revolute pairs and no prismatic or cylindrical pairs (i.e. no components having relative translational movement).

[0085] In other embodiments, the hinges connecting the components forming the Watt four-bar linkage to each other may be arranged so that their axes are parallel to each other and oriented at 90° relative to the axis of rotation BB of the front steering wheel 7, i.e., orthogonal to the plane containing the axis of rotation BB of the front steering wheel 7. In other words, the hinge axes of the revolute pairs connecting the components of the four-bar linkage to each other are oriented so as to lie on a vertical plane parallel to the median plane of the motor vehicle, i.e., on a vertical plane extending in the driving direction of the motor vehicle.

[0086] This type of embodiment is Figures 21 to 25 Parts corresponding to those already described with reference to the preceding figures are denoted by the same reference numerals with "100" added thereto. Figures 21 to 25 Only the front steerable wheel 107 with the corresponding suspension 117 and the rotatable arm 109 is shown, while the motor vehicle, not shown, may be equipped with Figure 1 or a motor vehicle similar to the motor vehicle indicated by 1 in 20.

[0087] Fig.21 , 22 and 23 show an assembly comprising the front steerable wheel 107, the rotatable arm 109 with its steering axis AA and the suspension 117 with all its components. Fig.24 The same assembly is shown with the rotatable arm 109 removed, Fig.25 The Watt four-bar linkage is shown with the components also removed to show the wheel supports, wheels, shock absorber 122 with brake or damper 119 and spring 121 .

[0088] More specifically, this embodiment is provided with a suspension 117 having a Watt four-bar linkage, comprising: a rotatable arm 109, a first crank 131, a second crank 133 and a connecting rod 135. In practice, each crank 131, 133 is doubled. The two parts of each crank are located outside the connecting rod 135 located in the center.

[0089] The crank 131 is hinged to the rotatable arm 109 by means of a first hinge 131A and to the connecting rod 135 by means of a second hinge 131B. Similarly, the crank 133 is hinged to the rotatable arm 109 by means of a first hinge 133A and to the connecting rod 135 by means of a second hinge 133B. The axes of the hinges 131A, 131B, 133A, 133B are parallel to each other and oriented at 90° relative to the rotation axis BB of the front steering wheel 107. In this embodiment, the orientation direction of the hinge axis of the Watt four-bar linkage is denoted by CC, see Fig.23 In practice, the hinge axis of the four-bar linkage is oriented orthogonally to a plane containing the axis of rotation BB of the front steering wheel 107 and substantially parallel to the direction of the spring movement.

[0090] The cranks 131, 133 have substantially the same length. The connecting rod 135 is hinged to the wheel support 137 at a midpoint between the axes of the hinges 131B, 133B. The wheel support 137 is hinged to the connecting rod 135 about a hinge axis oriented in the CC direction (i.e., an axis parallel to the axis of the hinge of the Watt four-bar linkage). The hinge axis connecting the wheel support 137 and the connecting rod 135 intersects and is orthogonal to the rotation axis BB of the front steering wheel.

[0091] In the illustrated embodiment, the wheel support 137 has a fork shape surrounding the connecting rod 135, such as Fig.24 and 25 The wheel support 137 may also have a restraining portion for connecting to the shock absorber 122. Figures 21 to 25 In the embodiment shown, the constraint between the wheel support 137 and the shock absorber 122 is an interlocking joint.

[0092] The wheel support 137 forms a swivel seat for the axle of the front steering wheel 107, not shown in the figures.

[0093] Specific as Fig.21As shown, the hinges 131B and 133A are located on one side of a plane, while the hinges 131A and 133B are located on the other side of the plane, which is orthogonal to the rotation axis BB of the front steering wheel 107 and approximately parallel to the direction of the spring movement of the suspension 117. From a different point of view, the hinges 131B, 133A are located on one side of the plane orthogonal to the rotation axis BB of the front steering wheel 107, while the hinges 131A, 133B are located on the other side of the plane. The reference plane may be, for example, a plane orthogonal to the rotation axis BB of the front steering wheel 7 and passing through the hinge 122A connecting the shock absorber 122 and the arm 109, or a plane orthogonal to the rotation axis BB of the front steering wheel and containing the hinge axis (oriented in the direction CC) between the connecting rod 135 and the wheel support 137.

[0094] During the spring movement of the front steerable wheel 107, the four-bar linkage of the suspension 117 deforms with the pivoting movement of the cranks 131, 133 relative to the rotatable arm 109 and the pivoting movement of the connecting rod 135 about the hinge axis (via which the connecting rod is connected to the wheel support 137). The construction of the Watt four-bar linkage formed by the components 109, 131, 133, 135 is also such that the hinge between the connecting rod 135 and the wheel support 137, and therefore the hinge axis CC, moves according to a substantially straight line trajectory during the entire spring movement. Since the wheel support 137 is rigidly connected to the shock absorber 122, the swinging of the connecting rod 135 has no effect on the camber angle of the front steerable wheel 107.

[0095] In the above embodiments, reference is made to a two-wheeled motor vehicle with a single front steerable wheel 7 or 107. However, the suspension of the invention can also be used for a leaning ride-on vehicle with two front steerable wheels, which are provided with, for example, one or two four-bar linkages to ensure the rolling motion of the motor vehicle during travel. Figure 26 to Figure 28 The schematic diagram of the tilt riding type motor vehicle 201 has a frame 203, a rear drive wheel 205 and two front steering wheels 207X and 207Y located on the left and right sides respectively. The two front steering wheels 207X and 207Y are arranged side by side in the lateral direction of the vehicle 201, that is, in the left-right direction.

[0096] exist Fig.26 , 27 In the embodiment schematically shown in Figures 209 and 209Y, reference numerals 209X and 209Y denote two rotatable arms having the same function as the single rotatable arm 9, 109 described with reference to the previous embodiment of the motor vehicle with a single front steering wheel. Each rotatable arm 209X, 209Y is adapted to rotate about the steering axis AA.

[0097] For this purpose, each rotatable arm 209X, 209Y is rotatably accommodated in a support or column 226X, 226Y, which is part of a rolling four-bar linkage 220. The two supports or columns 226X, 22Y are connected to each other by a corresponding upper crossbeam 222 and a lower crossbeam 224. The crossbeams 222, 224 and the supports 226X, 226Y form a rolling four-bar linkage 220 and are articulated to each other around hinge axes that are parallel to each other and are located on a plane oriented in the front-rear direction of the motor vehicle 201.

[0098] Reference numeral 215 denotes a handlebar, via which a steering movement about the axis AA is imparted to the support arms 209X, 209Y by means of a steering column 211 acting on a steering rod 230 .

[0099] The above-described rolling four-bar linkage is known per se and does not require a more detailed description.

[0100] Each front steering wheel 207X, 207Y is connected to its rotatable arm 209X, 209Y by means of a suspension 217X, 217Y which can be referred to as Figures 1 to 25 Designed in any of the ways described. Figure 26-28 In the configuration of suspension 217X and 217Y Figures 1 to 6 same.

Claims

1. A riding motor vehicle (1; 101; 201) having at least one rear drive wheel (5; 105; 205) and at least a first front steering wheel (7; 107; 207X, 207Y) connected to a rotatable arm (9; 109; 209X, 209Y) providing a rotational movement about a steering axis (AA); wherein A wheel support (37; 137) is connected to a rotatable arm (9; 109; 209X, 209Y) through the intervention of a suspension (17; 117; 217X, 217Y) including a shock absorber (22; 122), wherein the wheel support (37; 137) supports a front steering wheel (7; 107; 207X, 207Y) and defines a rotation axis (BB) of the front steering wheel (7; 107; 207); characterized in that the suspension includes a Watt's four-bar linkage; wherein the Watt's four-bar linkage and the shock absorber (22; 122) rotate together with the wheel support (37; 137) and the rotatable arm (9; 109; 209X, 209Y) around the steering axis (AA).

2. A motor vehicle (1; 101; 201) according to claim 1, wherein the Watt's four-bar linkage comprises a first crank (31; 131) hinged to the rotatable arm (9; 109) via a first hinge (31A; 131A) and hinged to the connecting rod (35; 135) of the Watt's four-bar linkage via a second hinge (31B; 131B), a first crank (31; 131) hinged to the rotatable arm (9; 109) via a first hinge (33A; 133A) and hinged to the connecting rod (35; 135) of the Watt's four-bar linkage via a second hinge (31B; 131B), 33B; 133B) is hinged to a second crank (33; 133) of a connecting rod (35; 135); and wherein the wheel support (37; 137) is constrained in a constraint point of the connecting rod (35; 135) so that the rotation axis (BB) of the front steering wheel (7; 107) is approximately equidistant relative to the second hinge (31B; 131B) of the first crank (31; 131) and relative to the second hinge (33B; 133B) of the second crank (33; 133).

3. A motor vehicle (1) according to claim 2, wherein the wheel support (37) is constrained to the connecting rod (35) so that the rotation axis (BB) of the front steering wheel (7) is parallel to the axes of the first hinge (31A) and the second hinge (31B) of the first crank (31) and the axes of the first hinge (33A) and the second hinge of the second crank (33).

4. A motor vehicle (1) according to claim 3, wherein the wheel support (37) is rigidly connected to the connecting rod (35) and forms a housing for a bearing which supports the front steering wheel (7).

5. A motor vehicle (1) according to claim 2, 3 or 4, wherein the axes of the first hinge (31A) and the second hinge (31B) of the first crank (31) and the axes of the first hinge (33A) and the second hinge (33B) of the second crank (33) are parallel to the rotation axis (BB) of the front steering wheel (7).

6. A motor vehicle (1) according to claim 2, 3 or 4, wherein the first hinge (31A) of the first crank (31) and the second hinge (33B) of the second crank (33) are located on a first side of a plane containing the axis of rotation (BB) of the front steering wheel (7) and passing through the constraint point (22A) of the shock absorber (22) to the rotatable arm (9); and wherein the second hinge (31B) of the first crank (31) and the first hinge (33A) of the second crank (33) are located on a second side of said plane.

7. A motor vehicle according to claim 2, 3 or 4, wherein relative to the direction of travel of the motor vehicle (1): The first hinge (31A) of the first crank (31) and the second hinge (33B) of the second crank (33) are in a rearward position, while the second hinge (331B) of the first crank (31) and the first hinge (33A) of the second crank (33) are in a forward position; or The first hinge (31A) of the first crank (31) and the second hinge (33B) of the second crank (33) are in a forward position, while the second hinge (31B) of the first crank (31) and the first hinge (33A) of the second crank (33) are in a rearward position.

8. A motor vehicle (101) according to claim 2, wherein the axes of the first hinge (131A) and the second hinge (131B) of the first crank (131) and the axes of the first hinge (133A) and the second hinge (133B) of the second crank (133) are substantially parallel to each other and orthogonal to a plane containing the axis of rotation (BB) of the front steering wheel (107).

9. A motor vehicle (1) according to claim 8, wherein the first hinge (131A) of the first crank (131) and the second hinge (133B) of the second crank (133) are located on a first side of a plane that is orthogonal to the axis of rotation (BB) of the front steering wheel (107) and passes through the constraint point (122A) of the shock absorber (122) to the rotatable arm (109); and wherein the second hinge (131B) of the first crank (133) and the first hinge (133A) of the second crank (133) are located on a second side of the plane.

10. A motor vehicle (101) according to claim 8, wherein the wheel support (137) is hinged to the connecting rod (135) about an axis (CC) which is substantially parallel to the axes of the first hinge (131A) and the second hinge (131B) of the first crank (131) and the axes of the first hinge (133A) and the second hinge (133B) of the second crank (133).

11. A motor vehicle (101) according to claim 10, wherein the hinges of the Watt four-bar linkage are arranged relative to a plane parallel to a plane in which the wheel (107) is located and which passes through the hinge axis (CC) between the wheel support (137) and the connecting rod (135) so that: the first hinge (131A) of the first crank (131) and the second hinge (133B) of the second crank (133) are located on one side of the plane, and the second hinge (131B) of the first crank (131) and the first hinge (133A) of the second crank (133) are located on the other side of the plane.

12. A motor vehicle (101) according to claim 10, wherein the wheel support (137) supports the front steered wheel (107) in a position where the rotation axis (BB) of the front steered wheel (107) is orthogonal to the axis about which the wheel support (137) is hinged to the connecting rod (135).

13. A motor vehicle (1; 101; 201) according to any one of claims 1, 2, 3, 4, 8, 9, 10, 11 and 12, comprising a disc brake having a caliper (25, 125) and a disc (23; 123) integral with a front steering wheel (7; 107; 207X, 207Y), wherein the caliper is rigidly connected to the wheel support (37; 137).

14. A motor vehicle according to any one of claims 1, 2, 3, 4, 8, 9, 10, 11 and 12, comprising a disc brake having a caliper (25, 125) and a disc (23; 123) integral with a front steering wheel (7; 107; 207X, 207Y), wherein the caliper is rigidly connected to a support member mounted idling relative to a connecting rod (35; 135) and a wheel support (37; 137).

15. A motor vehicle (1; 101; 201) according to any one of claims 1, 2, 3, 4, 8, 9, 10, 11 and 12, wherein the shock absorber (22; 122) is connected on one side to the rotatable arm (9; 109; 209X, 209Y) and on the other side to a location rigidly connected to a link (35; 135) of a Watt four-bar linkage.

16. A motor vehicle (1; 101; 201) according to any one of claims 1, 2, 3, 4, 8, 9, 10, 11 and 12, wherein the shock absorber (22; 122) is connected on one side to the rotatable arm (9; 109; 209X, 209Y) and on the other side to a point rigidly connected to the wheel support (37; 137).

17. A motor vehicle (1; 101; 201) according to any one of claims 1, 2, 3, 4, 8, 9, 10, 11 and 12, wherein the shock absorber (22; 122) is connected on one side to a rotatable arm (9; 109; 209X, 209Y) and on the other side to an axle of a front steering wheel (7; 107; 207X, 207Y) rotatably supported on a wheel support (37; 137).

18. A motor vehicle (1; 101; 201) according to any one of claims 1, 2, 3, 4, 8, 9, 10, 11 and 12, wherein the shock absorber (22; 122) is connected on one side to the rotatable arm (9; 109; 209X, 209Y) and on the other side to a link (35; 135) of a Watt four-bar linkage.

19. A motor vehicle (201) according to any one of claims 1, 2, 3, 4, 8, 9, 10, 11 and 12, comprising a second front steered wheel (207X, 207Y) connected to a second rotatable arm (209X, 209Y) providing a rotational movement about a second steering axis (AA) and connected to a wheel support of the second front steered wheel through the intervention of a second suspension (217X, 217Y); wherein the second suspension comprises a shock absorber and a Watt's four-bar linkage that is substantially symmetrical to the Watt's four-bar linkage of the suspension of the first front steered wheel relative to a mid-plane of the motor vehicle; and wherein the first front steered wheel (207X) and the second front steered wheel (207Y) are connected to the frame (203) of the motor vehicle (201) by means of a rolling four-bar linkage (220) hinged to the frame (203).

20. A motor vehicle (201) according to claim 19, wherein a first rotatable arm (209X) connected to the first front steering wheel (207X) and a second rotatable arm (209Y) connected to the second front steering wheel (207Y) are rotatably supported in corresponding left and right columns (226X, 226Y) of a rolling four-bar linkage (220), the columns being connected to each other by a first cross beam (222) and a second cross beam (224), the first cross beam and the second cross beam extending in the left and right directions relative to the middle plane of the vehicle and being hinged to the columns (226X, 226Y).

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