WO2017064631A1

WO2017064631A1 - Motorcycle

Info

Publication number: WO2017064631A1
Application number: PCT/IB2016/056105
Authority: WO
Inventors: Carmine DI NUZZO
Original assignee: Scuter S.R.L.
Priority date: 2015-10-16
Filing date: 2016-10-12
Publication date: 2017-04-20
Also published as: ITUB20155284A1

Abstract

Motorcycle with two front steering wheels (4, 4), comprising a frame (10) adapted to support a forecarriage comprising a suspension system comprising an arm, for each of the two front steering wheels (4, 4), a damper, for each arm, having a lower end connected to the respective arm and an upper end connected to interconnecting means connected to the frame, wherein the arm is an articulated arm which comprises a first and a second element hinged to each other, the first element comprises one end hinged to the frame and the second element is hinged to the other end of the first element and is connected to coupling means adapted to support a respective wheel (4), the interconnecting means comprise a joint hinged to the first element and the damper is connected between the joint and the second element.

Description

MOTORCYCLE

DESCRIPTION TECHNICAL FIELD

The present invention relates to the field of vehicles, particularly to motorcycles with three wheels two of which being front steering wheels.

The invention particularly relates to a motorcycle according to the preamble of claim 1.

PRIOR ART

Nowadays the use of three-wheeled motorcycles is more and more widespread, this is the safest solution for people that decide to renounce cars for moving even though having no experience with two-wheeled motorcycles, thus overcoming difficulties such as traffic, parking and road traffic limits.

One of the most crucial aspects and requiring attention in developing motorcycles with two front wheels is the forecarriage that comprises a suspension and steering system designed for guaranteeing the vehicle control when in motion.

Patent EP1155950 describes a three-wheeled vehicle, wherein the two front wheels are supported by a forecarriage in turn hinged to a rear axle of the frame. The front suspension is composed of a shock absorber interposed between the forecarriage and the frame. The steering assembly provides a pair of articulated rods arranged in sequence to transmit the motion from one end of the steering column to the two wheels. The steering column runs in a pair of sleeves connected to the forecarriage and to the rear frame respectively. An articulated quadrilateral has two horizontal rods hinged to the forecarriage and two vertical rods hinged to the supports of the two wheels.

Although efficient, such solution with a single central shock absorber is not fully satisfying.

A different type of suspension and steering assembly for motorcycles with two front wheels is known from European patents EP1339599 and EP2196386. The suspension system is composed of a swing arm connected to each wheel and hinged at one end to the frame, on each one of them a suspension is further connected to absorb vibrations during the travel. The steering system on the contrary generally provides a cascade of rods connected with each other by means of joints, for example connections of the articulated quadrilateral type, that allow the rotation of the handlebar to be transferred to both the wheels.

However even such suspension and steering systems involve limits in using motorcycles provided with them. A first drawback is the positioning of dampers, placed near the frame, that lead to a poor sensitivity of the suspension system in absorbing vibrations deriving from the travel.

A second drawback is the use of complicated mechanisms for interconnecting the two systems, which involves high encumbrance of the forecarriage and it considerably increases motorcycle weight, affecting both driving maneuverability and accuracy, and consumption-related efficiency.

OBJECTS AND SUMMARY OF THE INVENTION

It is the object of the present invention to overcome prior art drawbacks.

Particularly it is the object of the present invention to provide a motorcycle with two front steering wheels equipped with a suspension system having high comfort and sensitivity characteristics.

It is also an object of the present invention to provide a motorcycle with two front steering wheels equipped with a light and compact suspension system and steering system.

A further object of the present invention is to provide a motorcycle with two front steering wheels that is easy to be maneuvered and accurate when driving.

These and other objects of the present invention are achieved by a motorcycle embodying the characteristics of the annexed claims, which are an integral part of the present description.

The idea at the base of the present invention provides a motorcycle with two front steering wheels provided with a frame supporting a forecarriage. The forecarriage comprises a suspension system providing an arm for each of the two front wheels, with one end pivotally connected to a transverse axis of the frame, and an opposite end connected to coupling means that support a respective wheel. The suspension system further comprises two dampers, each one provided with a lower end connected to the respective arm and an upper end connected to interconnecting means connected to the frame. Then the forecarriage comprises a steering system that provides a handlebar rigidly connected to a steering rod, and means adapted to transfer a rotational movement of the steering rod to the two front wheels.

Particularly each arm is an articulated arm comprising a first and a second element hinged to each other, wherein the first element comprises one end hinged to the frame and the second element is hinged to the other end of the first element and is connected to the coupling means adapted to support a respective wheel.

Moreover the interconnecting means comprise a joint, hinged to the first element, and the damper is connected between the joint and the second element.

Such solution allows the motorcycle to have a comfortable driveability and a sensitive response of the suspension system, since the provision of an arm articulated into two relatively swing elements, and the particular arrangement of the damper, namely connected to such swing elements and in turn movable with respect thereto, allows both vibrations to be absorbed in the point where they are generated and the swing of the front wheels to be articulated on a higher number of degrees of freedom.

In one embodiment of the invention, the steering rod of the motorcycle comprises a lower end from which a level protrudes, which is provided with a hole housing a pin rigidly fastened to a connection element. The connection element is integral with a transverse rod, wherein the opposite ends of the rod are each one connected to a respective front wheel.

Such solution allows a motorcycle to be obtained having a light and compact forecarriage, since the sensitivity of the suspension system allows the steering system to be configured with simple connections that reduce both weight and encumbrance of the vehicle.

Such characteristic allows vehicle driveability to be further improved since the reduced side and front encumbrance of the forecarriage guarantee a better maneuverability and also a better driving accuracy, with advantages to the safety aspect.

Further advantageous characteristics of the present invention will be more clear from the following description and from the annexed claims, that form an integral part of the present invention.

BRIEF DESCRIPTION OF THE DRAWINGS

The invention will be described below with reference to some not limitative examples, provided by way of example and not as a limitation in the annexed drawings. These drawings show different aspects and embodiments of the present invention and, where appropriate, reference numerals showing like structures, components, materials and/ or elements in different figures are denoted by like reference numerals. Figure 1 is an overview of a motorcycle with two front steering wheels according to the invention;

Figures 2A and 2B are a perspective view and an enlarged view of a detail- the steering system - of the motorcycle of figure 1;

Figures 3A and 3B are a rear perspective view and a front perspective view of the forecarriage of the motorcycle of figure 1 with some elements of the steering system omitted to allow details of the suspension to be seen.

DETAILED DESCRIPTION OF THE INVENTION

While the invention is susceptible of various modifications and alternative constructions, some non-limitative embodiments, provided by way of example, are described in details herein below.

It should be understood, however, that there is no intention to limit the invention to the specific disclosed embodiments but, on the contrary, the invention intends to cover all the modifications, alternative constructions and equivalents that fall within the scope of the invention as defined in the claims.

In the description below therefore the use of "for example", "etc.", "or" denotes non- exclusive alternatives without limitation, unless otherwise noted; the use of "also" means "among which, but not limited to" unless otherwise noted; the use of "includes/ comprises" means "includes/ comprises, but not limited to", unless otherwise noted.

References to "upper", "lower", "above", "below" and the like are to be intended with reference to an operating condition that is an installed condition of the device, unless otherwise noted. Figure 1 shows an overview of a motorcycle 1 with two front steering wheels according to the present invention.

The motorcycle 1 comprises a forecarriage 2 with two front wheels 4, a rear axle 3 intended to support a rear wheel 5, and a frame 10. In the shown embodiment, the frame comprises tubular struts 11 defining a compartment for covering at the top and for accommodating the driver and a passenger, if any, and a foot rest 12, the propulsion system of the motorcycle (not shown in the figure) and a driving transmission system being preferably provided underneath it.

However it is clear that in variant embodiments auxiliary equipment (such as for example lights and saddle) can be arranged in a different manner or can have a different shape, and the frame 10 can be configured such to provide solutions alternative to tubular struts, or the latter can follow paths different from the ones in the figure, or, for instance, the portions covering the driver can be omitted.

In a preferred embodiment, the motorcycle 1 is equipped with an electric propulsion system that for instance can provide brushless motors, permanent induction or synchronous motors, air and/ or liquid cooled motors, battery packs and a relevant electric connector system for recharging the motorcycle, for instance, in the public network of electric charging stations, such as those available in car/ scooter sharing services.

The forecarriage 2 comprises on the contrary a pair of steering wheels 4, to allow the motorcycle 1 to be steered, a suspension system and a steering system.

With reference to figures 2 A and 2B the steering system comprises a handlebar 6 pivo tally connected to one upper end of a steering column 61. The steering column 61 is free to rotate inside a sleeve 62, secured to the frame 10, and extends, through the sleeve, up to near the two front wheels.

At one lower end 61a of the steering column, a lever 63, integral thereto, protrudes along a plane substantially orthogonal to the axis of rotation of the steering column 61. The lever 63 is provided with a hole intended to house a pin 64. The pin passes through the thickness of the lever and is rigidly fastened to a connection element 65, integral with a transverse rod 66, at whose opposite ends a respective front wheel 4 is connected. Particularly each end of the transverse rod 66 is provided with a cylindrical hinge 67 pivotally connecting it to the fork end 68 of the respective wheel.

Thus the rotating motion of the steering column is converted into a translation motion of the transverse rod that keeps the two wheels at a constant distance and by means of the cylindrical hinges allows the motorcycle 1 to be steered.

For a simple and immediate understanding, figures 3A and 3B show the suspension system of the forecarriage 2 of the motorcycle 1, not provided with the steering system. In particular the suspension system comprises a pair of articulated arms 7, one for each front wheel 4, which are hinged to the motorcycle frame 10 such to cause them to rotate with respect to an axis a transverse to the frame.

More in details, each articulated arm 7 comprises a substantially triangular-shaped first element 71. The first element 71, at one end, is connected through a hinge 701 to a strut 101 of the frame 10 arranged in proximity of the foot rest 12 and transverse to the development direction of the motorcycle 1, and it has a tip 71a placed higher than the point of connection to the strut 101.

Particularly the embodiment shown in the figures, shows that the triangular element

71 is hinged to the hinge 701 in two points, from which a first 711 and a second branch 712 originate respectively. The first branch 711 at the free end has a rotational joint 712 and the second branch is curved upward with respect to the first branch 711 joining, at the tip 71a, with another branching 713 connected to the first branch in proximity of the joint 702.

The joint 702 allows the first triangular element 71 to be connected to a second element

72 of the articulated arm 7.

The second element 72 has a tubular structure provided with a housing 720 where a lower end 81 of a damper 8 is fitted and hinged.

More in details, the second element 72 is hinged to the joint 702 in two distinct points from which an upper branch and a lower branch originate. Both the branches are developed by defining an upper annular path 721 and a lower annular path 722 respectively. Such paths are connected by transverse bars 723 and define the housing The second element 72 of each one of the two articulated arms is further hinged, by means of a further rotational connection, to a spindle 73 connected to the fork end 74 supporting the wheel 4. In the described example, the rotational connections comprise each one an upper rotational joint 721a and a lower rotational joint 722a, and the upper annular path 721 and the lower annular path 722 provide each one a side flap coupled to a respective joint to allow the wheel to accomplish a relative movement with respect to the second element 72.

Thus the articulated arms 7 can be movable with at least two degrees of freedom, since they are pivotable, that is both the first element 71 with respect to the frame 10 and the second element 72 with respect to the first triangular element, and to the frame 10 in case of a possible dragging motion.

Each damper 8 is connected, by an upper end 82, to a double joint element 9. More in details the double joint element 9 comprises a first joint 91 and a second joint 92, kept together by side plates, a seat being provided therebetween, as one piece with the plates and intended to house a pin. The pin passes through the seat, the plates and the upper tip 71a of the first triangular element 71.

Such connection allows the double joint element 9 to accomplish a relative rotation on the upper tip 71a of the triangular element 71 of the articulated arm 7.

To each one of the first joints 91 the upper end 82 of a respective damper 8 is connected and to each one of the second joints 92 on the contrary an end of a respective idle rod 13 is connected, that at the opposite end, is connected to one end of a cross-member 14 through a further rotational connection.

The cross-member 14 in its central point is then fastened by a pin 15 to the sleeve 62 connected to the frame of the motorcycle 1 and housing inside it a portion of the steering column 61 (partially visible in the figures). Thus a asymmetric and relative movement of one of the two wheels along a direction orthogonal to the travel direction of the motorcycle 1, and therefore of a respective articulated arm 7, is compensated for both by the damper 8 and by the rotation of the cross-member 14 about its pin 15. From the above description it is clear how the connecting rod just described allows the above objects to be achieved.

It is clear for a person skilled in the art that is possible to make changes and variants to the solution described with reference to the above figures without for this reason departing from the scope of protection of the present patent as defined in the annexed claims.

For example the steering system can provide at the lower end of the steering column a helical toothed rack-pinion type meshing. The torque applied to the handlebar is transmitted from the steering column to the pinion through a double cardan joint. Therefore the pinion transmits to the rack an axial load that, by a pair of sides tie rods, each one fastened to the fork end, allows wheels to be steered.

Claims

1. Motorcycle (1) with two front steering wheels (4), comprising a frame (10) adapted to support a forecarriage (2), said forecarriage (2) comprising

- a suspension system comprising:

- an arm (7) for each of said two front steering wheels (4), said arm (7) comprising one end pivotally connected to a transverse axis of the frame (10), and an opposite end connected to coupling means adapted to support a respective wheel,

- a damper (8) for each arm, said damper having a lower end (81) connected to the respective arm and an upper end (82) connected to interconnecting means connected to the frame (10),

- a steering system comprising:

- a handlebar (6) rigidly connected to a steering rod (61),

- means adapted to transfer a rotational movement of the steering rod (61) to said two front steering wheels (4),

characterized by the fact that

said arm (7) is an articulated arm which comprises a first (71) and a second (72) element hinged to each other, wherein said first element (71) comprises one end hinged to the frame (10) and wherein said second element (72) is hinged to the other end of the first element (71) and is connected to the coupling means adapted to support a respective wheel,

by the fact that

the interconnecting means comprise a joint (9) hinged to the first element (71), and by the fact that said damper (8) is connected between said joint (9) and the second element (72).

2. Motorcycle (1) according to claim 1, wherein the first element (71) of the articulated arm (7) is a substantially triangular-shaped element that comprises a first (711) and a second branch (712) hinged to the frame (10), wherein said first branch has at one free end a rotational joint (702) connected to the second element (72), wherein said second branch (712) is curved upward with respect to the first branch (711).

3. Motorcycle (1) according to claim 2, wherein said first (711) and second (712) branch are connected by a further branching fastened at the top to the second branch in proximity of the joint (9) and at the bottom to the first branch (711) in proximity of the rotational joint (702).

4. Motorcycle (1) according to claim 1 or 2 or 3, wherein the second element (72) comprises a tubular structure provided with an upper annular path (721) and a lower annular path (722), in which the upper annular path (721) and the lower annular path (722) are connected by transverse bars (723), wherein each one of said upper and lower annular paths provides flaps coupling to a respective joint fastened to the wheel to allow the wheel to accomplish a relative movement with respect to the second element (72), and wherein the lower end (81) of the damper (8) is housed in a housing (720) defined by said annular paths.

5. Motorcycle (1) according to any one of the preceding claims, wherein said interconnecting means further comprise a pair of rods (13) each one hinged to each joint (9), wherein said pair of rods are further hinged to the ends of a cross member (14) pivotally connected to said frame (10).

6. Motorcycle (1) according to any one of the preceding claims, wherein the steering rod (61) comprises a lower end (61a) from which a lever (64) protrudes, wherein said lever (63) is provided with a pin (64) rigidly fastened to a connecting element (65) , wherein said connecting element (65) is integral with a transverse rod (66), wherein the opposite ends of said rod are each one connected to a respective one of said front wheels (4).

7. Motorcycle (1) according to any one of the claims from 1 to 5, wherein the steering rod (61) comprises at a lower end a double cardan joint connected to a helical toothed rack-pinion type meshing, wherein the rack is connected to a pair of side tie rods each one hinged to a respective front wheel (4).