Straddle-type vehicle equipped with rear wings

Abstract

Straddle‐type vehicle (1) comprising a frame (2); a swing arm (3) swingably supported by the frame (2) and supporting an axle (6) of a rear wheel (5); a pair of footrests (7) coupled to the frame (2); a pair of wings (8) coupled to the frame (2) having a substantially vertical development; wherein each wing (8) is arranged behind the footrests (7) and in front of the axle (6) of the rear wheel (5).

Description

STRADDLE-TYPE VEHICLE EQUIPPED WITH REAR WINGSDESCRIPTIONTECHNICAL FIELD

[0001] The present invention relates to the field of straddle-type vehicles, in particular motorcycles and, even more particularly, racing motorcycles equipped with wing systems to optimize the aerodynamics of the vehicle.BACKGROUND ART

[0002] The state of the art comprises various known solutions to optimize the aerodynamics of motorcycles.

[0003] An example in this sense is provided by the patent document WO2023238025A1, which discloses a fairing of a motorcycle shaped to improve the downforce thereof while taking a curve, i.e., when the vehicle is rolled on one side. However, this solution requires the driver to reach a very high roll angle that not all normal motorcyclists are capable of reaching.

[0004] Another known solution to optimize the downforce of the rear end of a motorcycle is known from the patent document WO2023228143A1. This solution comprises a rear wing positioned on the top of the rear end of the motorcycle. This wing allows an increase of the downforce of the motorcycle on the rear end and hence an increase in its stability, above all at high speeds. However, this solution optimizes downforce along a straight stretch and, on the contrary, decreases grip while taking a curve, i.e., when the motorcycle is rolled on one side. In fact, the air that flows over the rear wing creates a component normal to the ground that increases the grip of the motorcycle, but also a horizontal centrifugal component that tends to cause the motorcycle to lose stability. This component increases as the roll angle increases.

[0005] There is also a solution known from the patent document WO2022229726A1 to close the slipstream of the rider-motorcycle assembly via a boot shaped in a particular way. However, this is not a solution for the motorcycle, but for the motorcyclist.SUMMARY

[0006] These and other drawbacks of the prior art are now solved by a first aspect of the presentinvention that concerns a straddle-type vehicle comprising: a frame; a swing arm swingably supported by the frame and supporting an axle of a rear wheel; a pair of footrests coupled to the frame; a pair of wings coupled to the frame and having a substantially vertical development. Observing the vehicle from the side, each wing is arranged behind the footrests and in front of the axle of the rear wheel. The wings comprise a leading edge and a trailing edge connected to each other by an outer surface and an inner surface of the wing. The outer surface is the one facing outward from the frame, while the opposite inner surface is the one facing inward, i.e., toward the frame. This arrangement and shape of the rear wings allows the dual effect of closing as best as possible the slipstream created behind the driver and the motorcycle, thereby improving the aerodynamics, and of providing a downforce effect, when the vehicle is leaning to take the curve, thereby improving grip in the curve. This shape of the wing allows improved penetration of the air by the wing and a smaller detachment of the fluid vein that flows over the outer and inner sides of the wing.

[0007] In particular, the wings can be outwardly spaced in a right-left direction from a body supported by the frame. In this way, a channel is formed between the body and the wings for the passage of an airflow that is mainly used when the vehicle is rolled and the driver opens the leg toward the center of the curve. Moreover, as the wings are outwardly spaced from the body, they intercept the airflow exiting from the lower part of the driver's leg, minimizing turbulence and hence increasing the overall aerodynamics of the vehicle-driver assembly.

[0008] Each wing can be coupled to the frame via a support. The wing is thus cantilevered from the body, thanks to the support. The support can be a portion of the wing that connects to the body, which is in turn connected to the frame, so as to provide said coupling of the wing to the frame.

[0009] Preferably, the support can be connected to a bracket of the passenger footrest. In this way it is possible to mount the pair of wings as accessory on any road bike comprising passenger footrests. In practice, when it is not necessary to accommodate a passenger, for example while riding on a racetrack, the passenger footrests can be removed to accommodate in the relative brackets respective wings in accordance with the present invention.

[0010] Advantageously, the outer surface of each wing has a convex shape to prevent detachment of the fluid vein that flows over the outer part of the wing.

[0011] In particular, the inner surface of each wing has a concave shape, or a convex shape with a lesser convexity than that of the outer surface. This shape of the inner surface of the wing makes it possible to avoid detachment of the fluid vein that flows over the inside of the wing.

[0012] Observing the vehicle from the front or rear, the wings can converge toward a midplane of the vehicle in a top-down direction. In practice, the wings are arranged in a V, observing the vehicle in erect position from the rear and / or from the front.

[0013] Observing the vehicle from above, the wings can converge toward a midplane of the vehicle in a front-back direction. In practice, the wings are arranged in a V, observing the vehicle from above in erect position.

[0014] Preferably, each wing can be inclined so that its upper edge is at least in part more advanced than its lower edge. This structure of the wing allows the arrangement of the driver's leg to be followed when the feet are positioned resting on the driver footrests.

[0015] In particular, the wings can be arranged so as to lie at least in part behind the driver's ankles when the driver is sitting on the vehicle with the feet resting on the footrests. This specific arrangement of the wings allows a downforce to be generated when the driver opens the leg inside the curve in order to tackle it.

[0016] Preferably, each wing can have a twisted shape. This shape is in particular optimized according to the flow lines, to avoid detachments of the fluid vein and optimize the effects of the wings.

[0017] Each wing can be arranged below a saddle of the vehicle. This arrangement of the wings makes it possible to optimally close the slipstream that is created when the pilot-vehicle assembly advances at high speed along a straight stretch.

[0018] A second aspect of the present invention concerns a wing for a straddle-type vehicle having a twisted shape and an aerofoil shape with a rounded leading edge and a sharp trailing edge, comprising a support couplable to the frame. The wing thus conceived can be supplied as an accessory of the vehicle, to be mounted thereon when required. Preferably, the support of the wing is couplable to a bracket of the passenger footrest of the vehicle. In this way, any vehicle equipped with passenger footrests can adopt a wing in accordance with the present invention.

[0019] These and other advantages will be more apparent from the following description of an embodiment thereof, provided by way of non-limiting indicative example with reference to the accompanying drawingsDESCRIPTION OF THE DRAWINGS

[0020] In the drawings:- Fig. 1 illustrates a side view of a vehicle according to the present invention with a driver positioned straddling the vehicle;- Fig. 2 illustrates the vehicle inclusive of driver of Fig. 1 viewed from above;- Fig. 3 illustrates the vehicle inclusive of driver of Fig. 1 viewed from the rear;- Fig. 4 illustrates an axonometric detail view which places emphasis on a left rear wing of the vehicle of Fig. 1.- Fig. 5 illustrates an axonometric view of the vehicle according to the present invention with a driver positioned straddling the vehicle, when the vehicle is rolled on one side to take a curve and the driver opens the leg arranged toward the inside of the curve;- Fig. 6 illustrates a front view of the vehicle inclusive of driver of Fig. 5.- Fig. 7 illustrates a diagram of the flow lines and the relative speeds of a vehicle with driver rolled, such as in Fig. 5, sectioned with a transverse plane inclined by about 55 degrees, which develops according to front-rear and right-left directions of the vehicle, and which passes through the wings, as illustrated in the box in the top left;- Fig. 8 illustrates a rear view of a vehicle according to the present invention;- Fig. 9 illustrates a front view of the vehicle of Fig. 8;- Fig. 10 illustrates a side view of the vehicle of Fig. 8;- Fig. 11 illustrates a top view of the vehicle of Fig. 8.DETAILED DESCRIPTION

[0021] The following description of one or more embodiments of the invention refers to the accompanying drawings. The same reference numbers in the drawings identify identical or similar elements. The subject matter of the invention is defined by the appended claims. The technical details, structures or features of the solutions described below can be combined with one another in any way.

[0022] The directions front-rear F-B, right-left L-R, and top-down T-D are represented in the figures.

[0023] In the figures, the reference number 1 illustrates a straddle-type vehicle which hereinafter is abbreviated with the term "vehicle" for convenience.

[0024] Figs. 1-3 illustrate a vehicle 1 with its driver 100. As the vehicle 1 is a motorcycle, and in particular a road or racing motorcycle, the handlebars 13, the saddle 12 and the footrests 7 are arranged so that when the driver 100 is on board the vehicle 1, they take an almost fetal position, i.e., crouched, as illustrated in Figs. 1-3.

[0025] In Figs. 1-3, the pilot 100 and vehicle 1 assembly are represented in erect, i.e., vertical, position and with the driver's feet 130 resting on the footrests 7, meaning that the vehicle 1 is traveling along a straight stretch.

[0026] On the contrary, in Figs. 5-6 the pilot 100 and vehicle 1 assembly are represented leaning to one side. In particular, in Fig. 5-6 the vehicle 1 is rolled to take a curve and the driver 100 moves body and leg 120 toward the inside of the curve to facilitate entering the curve and increase the grip of the vehicle 1 with the ground.

[0027] Figs. 8-11 instead represent the vehicle 100 alone, i.e., without a driver 100.

[0028] In Figs.1-11 the vehicle 100 is a motorcycle, therefore hereinafter the term "vehicle" or "motorcycle" may be used alternatively.

[0029] As the motorcycle 1 has two wheels 4,5 arranged in line, it must roll, i.e., lean to one side to take a curve, to compensate for centrifugal force.

[0030] As better illustrated in Figs. 8-11, the motorcycle 100 is a road motorcycle and therefore comprises a body 9 that develops from the front toward the rear of the vehicle 100. Specifically, the body 9 comprises a front portion 9' shaped to laterally cover part of the engine 14 and split the air that the vehicle 1 encounters while moving forward. The body 9 further comprises a rear portion 9” shaped to cover the rear portion of the frame 2 and lying below the saddle 12 of the vehicle 1. The front portion 9' of the body 9 further comprises a fairing portion 9'”, which comprises, in a front view, the handlebars 13.

[0031] The body 9, as a whole, partly or completely covers the frame 2 and the engine 14.

[0032] The rear wheel 5 is connected to the frame 2 via a swing arm 3 that supports the axle 6 of the rear wheel 5. The front wheel 4 is connected to the frame 2 via a steering column that terminates at the top with the handlebars 13.

[0033] When the vehicle 1 moves forward, the vehicle 1 splits the air, which thus flows over the body 9 and the driver 100. Optimization of the flow lines that flow around the vehicle 1 and the driver 100 allows the aerodynamics of the vehicle 1 to be optimized.

[0034] In particular, in the rear area of the vehicle 1 the flow lines tend to create turbulence mainly due to the presence of the driver 100. There is thus the need to direct and guide these flow lines in order to prevent this turbulence and close the so-called slipstream that is created behind the driver 100 and the vehicle 1.

[0035] The vehicle 1 is thus provided with two wings 8, each arranged on one side of the vehicle 1.

[0036] These wings 8 are coupled and connected to the frame 2 and are thus subject to the pitching and rolling movements of the frame 2.

[0037] The wings 8 are not wings that develop according to the width of the vehicle 1, for example like those of an airplane, but are wings 8 having a substantially vertical development.

[0038] The wings 8 comprise a leading edge 8A and a trailing edge 8B, connected to each other by an outer surface 8E and an inner surface 8F of the wing 8. The wing 8 further comprises an upper edge 8C and a lower edge 8D.

[0039] The wings 8 are inclined forward and therefore, observing the vehicle 1 from the side as illustrated in Figs. 1 and 10, the upper edge 8C is more advanced than the lower edge 8D. This particular arrangement serves to follow the position that the leg 120 of the driver 100 takes when the feet 130 rest on the footrests 7.

[0040] The wing 8, viewed from the side as represented in Figs. 1 and 10, has a trapezoidal shape, although other shapes are possible.

[0041] As illustrated in Fig. 2, 8, 9, 11, the wing 8 also has an aerofoil shape, so that the leading edge 8A is rounded, while the trailing edge 8B is sharp, for example like the wings of airplanes.

[0042] The outer surface 8E of the wing 8, also called extrados, has a greater convexity than theconcavity of the inner surface 8F, also called intrados, as illustrated in Fig. 4. In an alternative, not illustrated, both the surfaces 8E, 8F are convex.

[0043] The wing 8 can also have a twisted shape, as illustrated in Fig. 4. The apex of the trailing edge 8B can thus be further toward the outside or inside than the base of the trailing edge 8B. Likewise, the apex of the leading edge 8A can be further toward the outside or inside than the base of the leading edge 8B. This shape makes it possible to optimize the flow lines at different heights from the ground, when the motorcycle 1 is vertical or rolled.

[0044] The wings 8 are arranged in the rear end of the vehicle 1, i.e., in the rear part thereof. Specifically, the wings 8 are arranged behind the driver 100 when seated on the saddle 12 with the feet 130 resting on the footrests 7. The wings 8 are arranged behind the area in which the ankles 110 are positioned when the feet 130 of the driver are on the footrests 7.

[0045] In particular, each wing 8, in a side view of the vehicle 1, is arranged behind the footrests 7 and in front of the axle 6 of the rear wheel 5, as illustrated in Figs. 1 and 10.

[0046] Each wing 8, in a side view of the vehicle 1, is also arranged above the footrests 7 and below the saddle 12.

[0047] The wings 8 are mounted cantilevered on the vehicle 1 and remain spaced from the body 9, as illustrated in Figs. 2, 3, 4, 5, 8, 9, 11.

[0048] Each wing 8 is connected to the frame 2 via a support 10, better illustrated in Fig. 4.

[0049] The support 10 extends from the inner surface 8F of the wing 8 and connects to the bracket 11. The bracket 11 can be, as illustrated in Fig. 4, the bracket 11 that supports the passenger footrests.

[0050] In practice, the bracket 11 normally supports the passenger footrest (not illustrated) and, by removing this from the bracket 11, it is possible to connect, in the same way, the support 10 of the wing 8. The wing 8 is then constrained to the bracket 11 via a pin 15, to prevent rotation around the pivot 16, as illustrated in Fig. 4.

[0051] Thanks to the shape of the support 10 and of the bracket 11, the wing 8 remains spaced from the rear portion 9” of the body 9 and between the body 9 and the inner surface 8F of the wing 8 anideal channel is created, inside which the air can flow and indicated with the reference "Al".

[0052] This ideal channel is at least in part closed by the leg 120 of the driver 100 when seated on the saddle 12 and the motorcycle 1 is moving forward along a straight stretch, as better illustrated in Fig. 3. In this operating condition of the vehicle 1, the flow lines of a first air flow FL' flow mainly on the outer surface 8E of the wings 8. The shape of the wings 8, in this condition, tends to close the slipstream and direct the flow lines of the first air flow FL' toward the midplane M, as illustrated in Fig. 2.

[0053] To obtain this effect, observing the vehicle 1 from above as illustrated in Fig. 2, the wings 8 are shaped and arranged to converge toward the midplane M of the vehicle 1 in a transverse rightleft R-L direction. In particular, the outer surface 8E of the wings is shaped so as to curve toward the midplane M proceeding from the front toward the rear of the vehicle 1.

[0054] The wings 8 are also arranged and shaped to converge toward the midplane M also in a top- down T-D direction, as illustrated in Fig. 3. In practice, the wings 8 are arranged in a "V" observing the vehicle 1 from the rear or from the front, as illustrated in Figs. 3, 8 and 9.

[0055] Thanks to this arrangement and shape of the wings 8, when the vehicle 1 is leaning to one side (rolled) to take a curve and the driver 100 opens the leg 120 inside the curve, as illustrated in Figs. 5 and 6, between the body 9 and the inside of the leg 120 of the driver 100 a gap is created, inside which a second air flow FL'' can pass as illustrated in Fig. 6. The second airflow FL'' that passes between the leg 120 of the driver 100 and the body 9, thus reaches the wing 8 and flows over both the inner surface 8F and the outer surface 8E of the wing 8, as schematized in Fig. 6.

[0056] As better illustrated in Fig. 7, the flow lines of the second air flow FL'' increase in speed in the area A2 (illustrated with darker shades) that is located outside the wing 8, i.e., on the side of the outer surface 8E, while they decrease in speed in the area Al (illustrated with lighter shades) located inside the wing 8, i.e., in the area between the body 9 and the wing 8. In this way, a greater pressure is created on the inner side of the wing 8 that generates a force F normal to the outer surface 8E. The force F can be divided into its two components Fn vertical to the ground and Fr horizontal to the ground, as illustrated in Fig. 5. The component Fn tends to increase the grip of the vehicle 1 traveling around the curve, pulling it toward the ground. The component Fn also generates a torque that opposes in part the torque generated by the centrifugal force that tends to straighten themotorcycle 1. The component Fr tends to oppose the centrifugal force to which the vehicle 1 is normally subject when it is rolled while traveling around a curve, thereby improving road holding. The component Fr also generates a torque that opposes in part the torque that tends to straighten the motorcycle 1 generated by the centrifugal force.

[0057] This effect gradually decreases as the driver 100 tends to close the leg 120 on the body 9 and the vehicle returns to the vertical position, as illustrated in Fig. 3. In this position of the leg 120 of the driver 100, the gap that is created between leg 120 and body 9 closes and the air flows over the leg 120 and then the outer surface 8E of the wing 8, as illustrated with the first air flow FL' of Fig.2.

[0058] The wing 8 according to the present invention can also be an independent object that can be marketed separately from the vehicle 1, for example as an accessory.

[0059] The wing 8, better illustrated in Fig. 4, thus has an aerofoil shape having a rounded leading edge 8A and a sharp trailing edge 8B and has a twisted shape. The wing 8 thus conceived also has a support 10 that allows it to be connected to the vehicle 1. In particular, as described above, the support 10 can be connected to a bracket 11 of the passenger footrest of the vehicle 1.

[0060] The present disclosure specifically concerns also the inventios defined as follows:A. Straddle-type vehicle (1) comprising:- a frame (2);- a swing arm (3) swingably supported by the frame (2) and supporting an axle (6) of a rear wheel (5);- a pair of footrests (7) coupled to the frame (2);- a pair of wings (8) coupled to the frame (2) having a substantially vertical development; where each wing (8) is arranged behind the footrests (7) and in front of the axle (6) of the rear wheel (5); and wherein the wings (8) comprise a leading edge (8A) and a trailing edge (8B) connected to each other by an outer surface (8E) and an inner surface (8F) of the wing (8).B. Straddle-type vehicle (1) comprising:- a frame (2);- a swing arm (3) swingably supported by the frame (2) and supporting an axle (6) of a rear wheel (5);- a pair of footrests (7) coupled to the frame (2);- a pair of wings (8) directly or indirectly stably constrained to the frame (2); wherein each wing (8) is arranged behind the footrests (7) and in front of the axle (6) of the rear wheel (5); and wherein the wings (8) develop mainly in a vertical direction and comprise a leading edge (8A) and a trailing edge (8B) connected to each other by an inner surface (8F) of the wing (8), which faces a midplane (M) of the vehicle (1), and an opposite outer surface (8E) of the wing (8), which faces in right-left (R-L) direction outward from the midplane (M).

[0061] In conclusion, it is clear that the invention thus conceived is susceptible to numerous modifications or variations, all covered by the invention; moreover, all details can be replaced by technically equivalent elements. In practice the amounts can be varied according to technical requirements.

[0062] Legend of reference numbers:1 straddle-type vehicle2 frame3 swing arm4 front wheel5 rear wheel6 axle (of the rear wheel)7 footrest8 wing8A leading edge (of the wing)8B trailing edge (of the wing)8C upper edge (of the wing)8D lower edge (of the wing)8E outer surface (of the wing)8F inner surface (of the wing)9 body9' front body portion9” rear body portion9” fairing body portion10 support11 bracket of the passenger footrest12 saddle13 handlebars14 engine15 pin16 pivot100 driver110 ankle (of the driver)120 leg (of the driver)130 foot (of the driver)M midplane (of the vehicle)F forceFn vertical force componentFr horizontal force componentFL' first airflowFL” second airflowAl area inside the wingA2 area outside the wing

Claims

CLAIMS1. Straddle-type vehicle (1) comprising:- a frame (2);- a swing arm (3) swingably supported by the frame (2) and supporting an axle (6) of a rear wheel (5);- a pair of footrests (7) coupled to the frame (2);- a pair of wings (8) coupled to the frame (2) having a substantially vertical development; wherein each wing (8) is arranged behind the footrests (7) and in front of the axle (6) of the rear wheel (5); wherein the wings (8) comprise a leading edge (8A) and a trailing edge (8B) connected to each other by an outer surface (8E) and an inner surface (8F) of the wing (8); and wherein the leading edge (8A) is rounded and the trailing edge (8B) is sharp.

2. Straddle-type vehicle (1) according to claim 1, wherein the wings (8) are outwardly spaced in a right-left (R-L) direction from a body (9) supported by the frame (2) and form a channel (Al) for an airflow between the body (9) and the respective inner surface (8F) of the wing (8).

3. Straddle-type vehicle (1) according to any one of the preceding claims, wherein each wing (8) is coupled to the frame (2) via a support (10).

4. Straddle-type vehicle (1) according to claim 3, wherein the support (10) is connected to a bracket (11) of a passenger footrest.

5. Straddle-type vehicle (1) according to any one of the preceding claims, wherein the outer surface (8E) of each wing (8) has a convex shape.

6. Straddle-type vehicle (1) according to claim 5, wherein the inner surface (8F) of each wing (8) has a concave shape, or a convex shape with a lower convexity than the outer surface (8E).

7. Straddle-type vehicle (1) according to any one of the preceding claims, wherein the wings (8) converge toward a midplane (M) of the vehicle (1) in a top-down (T-D) direction.

8. Straddle-type vehicle (1) according to any one of the preceding claims, wherein the wings (8) converge toward a midplane (M) of the vehicle (1) in a front-back (F-B) direction.

9. Straddle-type vehicle (1) according to any one of the preceding claims, wherein each wing (8) is inclined so that its upper edge (8C) is at least in part more advanced than its lower edge (8D).

10. Straddle-type vehicle (1) according to any one of the preceding claims, wherein the wings (8) are arranged so as to lie at least in part behind the ankles (110) of the driver (100), when the driver (100) sits on the vehicle (1) with the feet arranged on the footrests (7).

11. Straddle-type vehicle (1) according to any one of the preceding claims, wherein each wing (8) has a twisted shape.

12. Straddle-type vehicle (1) according to any one of the preceding claims, wherein each wing (8) is arranged below a saddle (12) of the vehicle (1).

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