Rear suspension device for scooters and scooters equipped with such a device

Abstract

The invention relates to a rear suspension device (10) for reducing the wheelbase of a two-wheeled vehicle (100) comprising a chassis (1). The suspension device includes a swing arm (11) having a pivoting attachment member (12) on the chassis (1), an attachment member (13) for a rotation axis (6a) of a rear wheel (6), and a mechanical connection member (14) to an elastic suspension means (15) intended to be fixed to the chassis (1).According to the invention, the suspension device (10) comprises, between the elastic suspension means (15) and the mechanical connecting member (14), a transmission mechanism (16) comprising: - a connecting rod (17) pivotally connected to the mechanical connecting member (14), and - a lever arm (18) connected at one end to the connecting rod (17) and at the other end to the elastic suspension means (15), and comprising a pivot arranged between the two ends and intended to be fixed to the chassis (1) of the vehicle (100). Figure for the abstract: Fig. 3.

Description

Title of the invention: Rear suspension device for a scooter and scooter equipped with such a device

[0001] The present invention relates to a rear suspension device for a scooter.

[0002] The invention finds a particularly important, although not exclusive, application in the field of all-terrain scooters, in particular all-terrain electric scooters.

[0003] A scooter is a personal transport vehicle comprising two wheels carrying a board on which the user stands, and provided with a handlebar. The board and the handlebar are fixed to a very simple frame, or chassis, comprising a flat beam, substantially horizontal, on a forked part of which is fixed an axis of rotation of a rear wheel, and a beam oblique with respect to the flat beam carrying a seat of the handlebar, the latter being fixed to the front wheel. The horizontal beam and the oblique beam can be fixed rigidly to each other or by means of a reversibly lockable joint in the case of foldable scooters.

[0004] Throughout this text, the arrangement of the different parts is given with reference to the rear / front direction Fl of the scooter in the normal use position, i.e. in forward motion.

[0005] Off-road scooters have large wheels designed to absorb uneven terrain and provide great stability through the gyroscopic effect.

[0006] In order to improve user comfort and off-road capabilities, all-terrain scooters, and in particular all-terrain electric scooters, have at least front suspension. The most efficient ones also have rear suspension, but the length imposed by this suspension prevents these scooters from being approved for road use in many countries.

[0007] Conventional rear suspensions comprise a swing arm comprising two attachment parts: a first attachment part to the axis of rotation of the wheel, and a second attachment part to the chassis. The second attachment part comprises, on the one hand, a pivot provided with an axis of rotation fixed relative to the chassis and, on the other hand, an axis, movable relative to the chassis, for attaching a first end of an elastic means, such as a spring-shock absorber combination. A second end of the elastic means is finally attached to a second portion of the chassis by an axis of rotation fixed relative to the chassis.

[0008] In other words, the wheel axle is not fixed to the chassis directly, but by means of the swing arm which is fixed to the chassis by a fixed point and a point elastically mobile.

[0009] A first known solution is illustrated in Figures 1 and 2. The scooter A comprises a rear wheel B fixed to the chassis C by means of a swing arm D, triangular in side view. This swing arm D comprises two triangular frames connected by a common side located in front of the rear wheel. The two triangular frames therefore have two common vertices DI and D2, and a specific vertex D3. Each specific vertex D3 is fixed to one end of the axle of the rear wheel.

[0010] The top DI is connected to the chassis C by a rotation axis which is fixed relative to the chassis. The top D2 is fixed to a first end of an elastic means E (here a spring-shock absorber combination) by a rotation axis which is movable relative to the chassis. A second end of the elastic means E is fixed to the chassis C by a rotation axis which is fixed relative to the chassis.

[0011] In this configuration, the vertex D2 is arranged at a height Hd2 greater than the height Hdl of the vertex DI and to the height Hd3 of the vertex D3, relative to the direction F2 opposite to gravity.

[0012] Furthermore, the vertex DI is located in front of the wheel to allow the latter to move when it passes over the hump SL. The hump SI illustrated in Figures 1 to 4 is the maximum theoretical hump that can be crossed. It is formed by an arc of a circle tangent, in the rest position in which the suspension is not stressed, to the front and rear wheels and to the lower part of the chassis.

[0013] Although in this case the wheel pivots around the vertex D1, the distance and arrangement of the latter relative to the wheel axis means that the wheel moves essentially vertically in response to road irregularities. Thus, the wheel axis rises much more than it approaches the vertex DL. The arrow F3 illustrating this movement in [Fig. 2] is therefore slightly curved, but essentially vertical. In this case, the height of the vertex D2 changes very little and remains greater than the height of the other two vertices. On the other hand, the height Hd3 of the vertex D3, and therefore of the wheel axis, increases sharply and is between the height Hd2 of the vertex D2 and the height Hd1 of the vertex D1 (which is constant relative to the chassis).

[0014] The scooter comprises footrests arranged on either side of the spring-shock absorber assembly E, so that the user places his legs on either side of the spring-shock absorber E, and in front of the axis of rotation of the top D1 which is fixed relative to the chassis.

[0015] The disadvantage of this arrangement is the wheelbase L of the assembly (i.e. the distance between the axles of the wheels of the suspended scooter) which is necessarily greater than the regulatory length beyond which the scooter is not authorized to ride on the road or in town. In France, this regulatory length is 1.65 meters.

[0016] However, given their cost, it would be desirable for owners of such scooters to also be able to use them in the city and on the road for their travel. In addition, their stability due to the large wheels would greatly benefit the safety of users.

[0017] The general objective of the present invention is therefore to propose a rear suspension solution making it possible to reduce the wheelbase of a scooter.

[0018] The idea underlying the invention consists of proposing a partially inverted suspension device, the structure and arrangement of which allow actuation of the damping by the rear wheel in pulling (towards the rear of the scooter, in the opposite direction to direction F1) and not in pushing (towards the front of the scooter, in the direction of direction F1).

[0019] To this end, the invention relates to a suspension device intended for a two-wheeled vehicle which comprises a chassis, the suspension device comprising a swing arm having at least one pivoting attachment member on the chassis, at least one attachment member for an axis of rotation of a rear wheel, and at least one mechanical connection member to an elastic suspension means intended to be fixed to the chassis, the suspension device further comprising, between the elastic means and the mechanical connection member, a transmission mechanism comprising: - a connecting rod pivotally connected to the mechanical connection member, and - a lever arm connected by a first end to the connecting rod and by a second end to the elastic means and comprising a pivot arranged between the two ends and intended to be fixed to the chassis of the vehicle.

[0020] According to particular embodiments, one and / or the other of the following provisions is also used: - the mechanical connection member may be arranged lower, with reference to the position of use, than the pivoting fixing member; - the suspension device may be intended for a two-wheeled vehicle which comprises a chassis having a flat portion having, with reference to a rear / front direction of the vehicle in the forward operating position, a rear end provided with a fork within which extends a part of a rear wheel which comprises an axis of rotation and a peripheral rolling part, the suspension device being shaped so that in the operating position, the pivoting fixing member is fixed on the fork of the chassis, in a grip of the wheel, at the rear of the peripheral rolling part and at the front of the axis of rotation of the rear wheel, with reference to a rear / front direction of the vehicle; - the pivoting chassis attachment member, the rear wheel axle attachment member and the mechanical connection member may form a triangle, seen laterally by relative to the rear / front direction of the vehicle in the forward operating position, the mechanical connection member being arranged under the pivoting chassis attachment member and the rear wheel axle attachment member; - the swing arm may comprise at least one frame carrying in a triangular manner the pivoting attachment member to the chassis, the rear wheel axle attachment member and the mechanical connection member, the mechanical connection member being arranged under the pivoting attachment member; - the or each frame of the swing arm may comprise a suspension arm carrying at a first end the pivoting attachment member to the chassis, and at a second end the mechanical connection member, a plate carrying the rear wheel axle attachment member being fixed to the suspension arm; - the or each frame of the swing arm may comprise an L-shaped suspension arm carrying at a first end the pivoting attachment member to the chassis, carrying at a second end the rear wheel axle attachment member and carrying at a vertex of the L arranged between the first and second ends the mechanical connection member, and in which, with reference to the position of use, the mechanical connection member is arranged under the pivoting attachment member; - the swing arm may comprise two frames intended to be arranged laterally and on either side of the rear wheel of the vehicle, each frame carrying a pivoting attachment member to the chassis, a rear wheel axle attachment member, a mechanical connection member, and in which, with reference to the position of use, the mechanical connection members are arranged under the pivoting attachment member to the chassis and are each connected to a connecting rod, the connecting rods being connected to the first end of the lever arm by a common axis of rotation; - the suspension device may be shaped so that in the rest position in which the elastic suspension means is not compressed, the pivoting chassis attachment member is arranged above the or each rear wheel axle attachment member, and so that in the activated position in which the elastic suspension means is compressed, the pivoting chassis attachment member is arranged below the or each rear wheel axle attachment member; - in the rest position, the pivoting attachment member and the or each rear wheel axle attachment member may have a first height difference, and in the activated position the pivoting attachment member and the or each rear wheel axle attachment member may have a second height difference, the first height difference and the second height difference being identical in absolute value; - the swing arm may further comprise a rear mudguard attachment hoop arranged above the rear wheel; - the suspension device can be shaped so that in the position of use, the attachments of the lever arm and the elastic suspension means are aligned in a median longitudinal plane of the chassis passing through a median plane of the front and rear wheels, such that the lever arm and the elastic suspension means are aligned in said median longitudinal plane of the chassis; - the suspension device may further comprise a protective casing covering at least the lever arm; and / or - the casing can also cover the elastic suspension means.

[0021] The invention also relates to a scooter comprising a preceding suspension device, and a chassis having a flat portion having, with reference to the position of use, a rear end provided with a fork within which extends a part of a rear wheel having an axis of rotation, the suspension device being arranged so that in the position of use: - the pivoting fixing member is fixed to the end of the chassis fork, to the rear of the peripheral rolling part and to the front of the wheel rotation axis, with reference to a rear / front direction of the vehicle; and so that - the fixings of the lever arm and the elastic suspension means are aligned in a median longitudinal plane of the chassis passing through a median plane of the front and rear wheels, such that the lever arm and the elastic suspension means are aligned in said median longitudinal plane of the chassis.

[0022] According to particular embodiments: - the scooter may further comprise a footrest on either side of the lever and the elastic suspension means, and intended to receive the feet of a user in use; and / or - the scooter may also include a protective casing covering at least the lever arm.

[0023] Other characteristics of the invention will be set out in the detailed description below given with reference to the appended figures given by way of example, and which represent, respectively:

[0024] [Fig.l], a schematic side view of a suspended scooter known from the state of the art in the rest position, the suspension not being stressed;

[0025] [Fig.2], a schematic side view of the scooter of [Fig.l], in the activated position, the suspension being stressed;

[0026] [Fig.3], a schematic side view of a suspended scooter according to the invention, equipped with a first embodiment of a rear suspension device, in the rest position, the suspension not being stressed;

[0027] [Fig.4], a schematic side view of the scooter of [Fig.3], in the activated position, the suspension being stressed;

[0028] [Fig.5], a schematic perspective view of the first embodiment of the suspension device according to the invention, further comprising a part for fixing a rear mudguard;

[0029] [Fig.6], a partial front perspective schematic view of a user positioned on a scooter according to the invention;

[0030] [Fig.7], a schematic perspective view of a second embodiment of a suspension device according to the invention; and

[0031] [Fig.8], a schematic perspective view of a third embodiment of a suspension device according to the invention.

[0032] Generally, the present description is made with reference to the position of use on a scooter or of the scooter. In this position of use, the scooter has a backward / forward direction Fl defined by the forward position of use.

[0033] The scooter also has a top and a bottom relative to the direction F2 opposite to gravity. The lowest points of the scooter are the points of the front and rear wheels in contact with the ground S and the bumps SI of the ground. The relative heights of the different elements are given relative to the chassis and the direction F2.

[0034] The relative position of the different elements of the scooter and of the suspension device according to the invention is described with respect to these directions F1 and F2.

[0035] Furthermore, the operation and structure of the suspension device according to the invention are described with respect to two positions: - a so-called “rest” position in which the elastic suspension means is not compressed, i.e. when the suspension is not stressed. In this case, the two wheels are in contact with flat ground referenced “S”; and - a so-called "activated" position in which the elastic suspension means is compressed, i.e. when the suspension is stressed. In this case, the rear wheel is in contact with a bump referenced "SI" on the ground S.

[0036] [Fig.3] illustrates a scooter 100 equipped with a suspension device according to the invention for the rear wheel.

[0037] The scooter 100 comprises a chassis 1 carrying footrests 2 on which a user stands (see [Fig.6]). At the front, the chassis 1 is secured to a handlebar 3 connected to a fork 4 fixed to a front steering wheel 5. The fork 4 may or may not be suspended.

[0038] The footrests 2 are fixed to a flat portion 1a of the chassis 1 which comprises a rear end 1b provided with a fork within which extends a part of a rear wheel 6 having an axis of rotation 6a (see [Fig.6]). The rear wheel 6 is advantageously driven and provided with an electric motor connected to a battery 7 carried by the chassis.

[0039] The scooter 100 according to the invention comprises a suspension device 10 comprising a swing arm 11 having at least one pivoting fixing member 12 on the chassis 1, at least one fixing member 13 of an axle of a rear wheel, and at least one mechanical connection member 14 to an elastic suspension means 15 fixed to the chassis 1.

[0040] More precisely, the swing arm 11 comprises a frame 11a carrying, arranged in a triangular manner, the pivoting fixing member 12 to the chassis, the rear wheel axle fixing member 13 and the mechanical connection member 14, the mechanical connection member 14 being arranged under the pivoting fixing member 12.

[0041] According to the invention, the suspension device comprises, between the elastic means 15 and the mechanical connection member 14, a transmission mechanism 16 which reverses the actuation of the elastic means 15 by the rear wheel.

[0042] The transmission mechanism 16 comprises:

[0043] - at least one connecting rod 17, visible in figures 3 and 4, the part of which is located under the footrest is shown in local section, pivotally connected to the mechanical connection member 14, and

[0044] - a lever arm 18, visible in figures 3 and 4, the part of which is located under the footrest is shown in local section.

[0045] The lever arm 18 is connected by a first end 18a to the connecting rod and by a second end 18b to the elastic means 15. It also comprises a pivot 18c arranged between the two ends 18a-18b and fixed to the chassis 1 in the flat portion 1a, in front of the rear wheel 6.

[0046] The pivoting fixing member 12 is fixed to the rear end 1b of the chassis 1 by a fixing lug 1c, and the pivot 18c of the lever arm 18 is fixed to the flat part 1a of the chassis 1 by a fixing lug 1d. The elastic suspension means 15 is fixed to the end 18b of the lever arm by an end 15a, and to a fixing lug 1c of the chassis 1 by an end 15b.

[0047] The fixing lugs 1c, 1d and 1c provide the function of pivot axis bearings, allowing the mechanical connection in rotation on the chassis of the pivoting fixing member 12 of the swing arm 11, of the lever arm 18 and of the elastic suspension means 15.

[0048] [Fig.3] illustrates the scooter 100 in the rest position. In this position, the elastic suspension means 15 has a rest length L1.

[0049] [Fig.4] illustrates the scooter 100 in the active position. In this position, the means The suspension elastic 15 has an activation length L2, allowing it to absorb the movement of the rear wheel when the scooter rolls over a bump, for example.

[0050] At rest, the pivoting fixing member 12 is at a constant height H12 by relative to the chassis 1. The fixing member 13 is at a height H13 and the mechanical connection member 14 is at a height H14, the heights H13 and H14 being variable relative to the chassis.

[0051] The pivoting fixing member 12, the rear wheel axle fixing member 13 and the mechanical connection member 14 form a triangle (represented by a triangle T in dashed lines and dots in the figures), seen laterally with respect to the rear / front direction Fl of the scooter in the forward operating position.

[0052] At rest (see [Fig.3]), the pivoting fixing member 12 is arranged above the rear wheel axle fixing member 13 and the mechanical connection member 14.

[0053] In the activated position (see [Fig.4]), the pivoting fixing member 12 is below the rear wheel axle fixing member 13 which follows a rotational movement, but essentially upward according to the arrow F3, up to a height H13'. Concomitantly, the mechanical connection member 14 undergoes an upward rotational movement, but essentially a rearward traction movement according to the arrow F4, which drives the connecting rod 17 upwards to a height H14' and towards the rear.

[0054] In other words, the swing arm is shaped so that in the rest position, the pivoting attachment member 12 and the or each rear wheel axle attachment member 13 have a first height difference dH1, and that in the activated position the pivoting attachment member 12 and the or each rear wheel axle attachment member 13 have a second height difference dH2.

[0055] In a preferred conformation, the first height difference dH1 and the second height difference dH2 are identical in absolute value.

[0056] Thus, if we define that the first height difference dH1 is equal to H12-H13, (the height H12 being constant and the height H13 being variable), and that the second height difference dH2 is equal to H12-H13', we understand that the height difference dH1 is positive since in the rest position the rear wheel axle fixing member 13 is lower than the pivoting fixing member 12, whereas the height difference dH2 is negative since in the activated position the rear wheel axle fixing member 13 is higher than the pivoting fixing member 12.

[0057] The preferred configuration provides that the absolute value of these height differences between the two members 12 and 13 between the rest position and the active position is identical. In other words, the pivoting fixing member 12 is arranged, seen laterally, at an equal distance (in height) from the rear wheel axle fixing member 13 in the rest position (H 13) and in the activated position (H13').

[0058] This configuration makes it possible to minimize the back-to-front movement of the rear wheel 6 during oscillations.

[0059] The connecting rod 17, integral with the end 18a of the lever arm 18, prints a pivoting movement of the lever arm 18 around the pivot 18c, which compresses the elastic suspension means secured to the end 18b of the lever arm 18.

[0060] Thus, when the suspension device according to the invention is stressed, the swinging arm compresses the elastic means 15 by pulling on the connecting rod 15 and pivoting the lever arm 18 of the transmission mechanism 16.

[0061] The transmission mechanism 16, intermediate between the swing arm 11 and the elastic suspension means 15, thus makes it possible to transmit the movement of the wheel by passing partially under the footrests 2, which limits the size of the device on the scooter.

[0062] Furthermore, the distance between the point of attachment of the connecting rod 17 on the end 18a of the lever arm, and the pivot 18c, is chosen to allow both the effective transmission of the rise of the rear wheel to the elastic suspension means 15, and to ensure that the connecting rod does not protrude too far under the footrests in order to maintain a high ground clearance.

[0063] Thus, as shown in Figures 3 and 4, when the maximum bump SI is located between the front and rear wheels ([Fig.3]), the connecting rod(s) located under the footrests 2, but in the rear position relative to the user (i.e. the connecting rod is mainly located in the grip of the wheel), do not touch the bump SI. When the rear wheel begins to climb over the bump SI and the latter approaches the rear of the scooter, the connecting rod retracts, because it moves back and up relative to the rest position. There is therefore no chance of the connecting rod touching the bump during crossing.

[0064] The arrangement according to the invention therefore makes it possible to reduce the wheelbase of the scooter while ensuring the suspension function of the rear wheel and preserving optimal ground clearance defined solely by the height of the chassis relative to the ground and not the height of the connecting rod in the rest position.

[0065] More precisely, the suspension device according to the invention is arranged on the scooter so that in the use position, the pivoting fixing member 12 is fixed in the grip of the rear wheel 6. In other words, the pivoting fixing member 12 is fixed to the end of the fork 1b of the chassis 1, to the rear of the peripheral rolling part 6b of the rear wheel 6 (i.e. to the rear of the tire) and to the front of the fixing member 13, therefore to the front of the axis of rotation 6a of the rear wheel 6, with reference to the rear / front direction F1 of the vehicle in the use position in forward gear.

[0066] According to the invention, the fixings of the lever arm 18 and of the elastic suspension means 15 are aligned in a median longitudinal plane Pm of the chassis passing through a median plane of the front and rear wheels. Thus, the lever arm and the elastic suspension means are aligned in said median longitudinal plane of the chassis and are located in the middle of the scooter, between the footrests. The user U can thus position his feet on either side of the lever arm 18 and the elastic suspension means 15 which can move freely even when the user U is on the scooter (see [Fig.6]). To avoid any risk, it is advantageous to provide a protective casing (not shown) covering at least the lever arm. Preferably, the casing also covers the part located between the mudguard 20 and the lever arm 18 to avoid any risk of pinching when the mudguard pivots downwards when the rear wheel rises upwards (for example when passing over a bump). The casing can also cover the elastic suspension means 15. For the mudguard 20 as for the elastic suspension means 15 which moves during shock absorption, it is important to provide either a two-part casing or a casing made of deformable material and / or structure.

[0067] A very simple embodiment consists of providing a swing arm engaged on only one side of the wheel.

[0068] As detailed in [Fig.5], to ensure good resistance, it is preferred to provide a double swing arm, engaged on both sides of the wheel 6.

[0069] In other words, the double swing arm comprises, on each side of the rear wheel 6, a pivoting fixing member 12 on the chassis 1 (shown in dotted lines), a fixing member 13 for the axle of the rear wheel 6, a mechanical connection member 14, a connecting rod 17 pivotally connected to the mechanical connection member 14, and a lever arm 18 (which may be unique) connected to the connecting rod 17 and to the elastic means 15, which is unique.

[0070] More precisely, the double swing arm 11 comprises two frames 11a intended to be arranged laterally and on either side of the rear wheel of the scooter, each frame 11a carrying a pivoting attachment member 12 to the chassis, a rear wheel axle attachment member 13 and a mechanical connection member 14. The mechanical connection members 14 are arranged under the pivoting attachment member 12 to the chassis and are each connected to a connecting rod 17, the connecting rods being connected to the first end 18a of the lever arm 18 by a common rotation axis.

[0071] More generally, in this configuration, the two pivoting attachment members 12, the two attachment members 13 of the axle of the rear wheel 6, the two mechanical connection members 14, and the two connecting rods 17 are connected to each other by rotation axes. In other words, the two pivoting attachment members 12, the two attachment members 13 of the axle of the rear wheel 6, the two mechanical connection members 14, and the two connecting rods 17 are articulated, two by two on the same rotation axis.

[0072] The lever arm can be single or double since it is arranged in a central position, that is to say in the median longitudinal plane of the scooter. If the lever arm 18 is double, as in [Fig.5], the two parts are also connected by an axis. This makes it possible to obtain a structure that is both solid, rigid and precise in its function, and light.

[0073] Advantageously, the two parts of the swing arm are connected to each other by a hoop 19 straddling the rear wheel 6. This hoop 19 secures the two parts of the arm and stiffens it. In particular, the configuration illustrated in [Fig.5] comprises a hoop 19 connecting the two pivoting fixing members 12.

[0074] The arch 19 further comprises two reinforcing legs 19a making it possible to reinforce the fixing of the plates 13a each carrying a fixing member 13 and fixed to the frames 11a of the swing arm 11. In particular, the plates are each fixed to a suspension arm 11 carrying at a first end a pivoting fixing member 12 to the chassis, and at a second end a mechanical connection member 14.

[0075] The hoop 19 can also provide a function of fixing a rear mudguard 20, as shown in Figures 3 and 4.

[0076] The pivot axis of the pivoting fixing member 12 is therefore closer to the axis of rotation of the wheel than in the swing arms of the state of the art.

[0077] The attachment 18c of the lever arm 18 and the attachment 1e-15b of the elastic suspension means are aligned in a median longitudinal plane of the chassis passing through a median plane of the front and rear wheels, such that the lever arm and the elastic suspension means are aligned in said median longitudinal plane Pm of the chassis.

[0078] [Fig.7] illustrates a second embodiment of a suspension device 101 according to the invention, simplified compared to the first embodiment illustrated in Figures 3 to 6.

[0079] In this embodiment, the swing arm 11 comprises two frames 11a intended to be arranged laterally and on either side of the rear wheel of the scooter.

[0080] As previously, each frame 11a carries a pivoting attachment member 12 to the chassis, a rear wheel axle attachment member 13 and a mechanical connection member 14 arranged in a triangular manner, the mechanical connection member 14 being arranged under the pivoting attachment member 12.

[0081] Unlike the first embodiment, the two frames 11a of the swing arm 11 are not connected by a hoop. They are connected to each other by the chassis 1 (shown in dotted lines) at the level of the attachment 1c of the pivoting attachment members 12, by an axis of rotation common to the mechanical connection members 14, and by the axis of rotation of the wheel fixed to the attachment members 13.

[0082] [Fig.8] illustrates a third embodiment of a suspension device 102 according to the invention. In this embodiment, the swing arm 21 comprises two 21a tubular frames.

[0083] Each frame 21a comprises an L-shaped suspension arm 21al carrying at a first end the pivoting fixing member 22 to the chassis 1 (shown in dotted lines), and at a second end the rear wheel axle fixing member 23.

[0084] The suspension arm 21al also carries, at the top of the L (i.e. at the tip of the L) arranged between the first and second ends, the mechanical connection member 24.

[0085] As previously, and according to the configuration of the invention, the mechanical connection member 24 is arranged under the pivoting fixing member 22 with reference to the position of use.

[0086] In a non-illustrated alternative of this third embodiment, the two frames 21a are connected by a hoop similar to the hoop 19 illustrated in [Fig.5], above the pivoting fixing members 22.

[0087] As in the first embodiment, the swing arms of the second and third embodiments are connected to the elastic suspension means 15 by a transmission mechanism comprising two connecting rods 17 each connected to a mechanical connection member 24, and a lever arm 18 connected to the common axis of the connecting rods 17 and to the elastic means 15.

[0088] The swing arms of the second and third embodiments are illustrated with two frames arranged on either side of the rear wheel, but it is also possible to design them with a single frame arranged on only one side of the rear wheel.

[0089] This allows the weight of the assembly to be reduced, but at the risk of weakening the suspension device.

[0090] The suspension device according to the invention makes it possible to reduce the wheelbase of the scooter while ensuring effective rear suspension and maintaining the crossing capabilities of prior art suspended scooters.

[0091] This reduction in the wheelbase makes it possible to meet the regulatory requirements of certain countries for approval of the scooter for road and city streets. It also makes it possible to reduce the size of the scooter, facilitating its use in the city as well as off-road. The large size of the wheels allows for very high stability of the scooter, thus reducing the risk of accidents if the scooter passes over road obstacles.

[0092] The suspension device according to the invention finds a particularly interesting application in the field of scooters and, in particular, electric scooters, but it can also be applied to certain scooters having a structure similar to the scooter, as well as a seat post and a saddle.

Claims

Claims

1. Suspension device (10, 101, 102) for a two-wheeled vehicle (100) which comprises a chassis (1), the suspension device comprising a swing arm (11) having at least one pivoting fixing member (12, 22) on the chassis (1), at least one fixing member (13, 23) of an axis of rotation (6a) of a rear wheel (6), and at least one mechanical connection member (14, 24) to an elastic suspension means (15) intended to be fixed to the chassis (1);characterized in that the suspension device (10, 101, 102) further comprises, between the elastic suspension means (15) and the mechanical connection member (14, 24), a transmission mechanism (16) comprising: - a connecting rod (17) pivotally connected to the mechanical connection member (14, 24), and - a lever arm (18) connected by a first end (18a) to the connecting rod (17) and by a second end (18b) to the elastic suspension means (15) and comprising a pivot (18c) arranged between the two ends (18a-18b) and intended to be fixed to the chassis (1) of the vehicle (100).;

2. A suspension device (10, 101, 102) according to claim 1, wherein the mechanical connecting member (14, 24) is arranged lower, with reference to the position of use, than the pivoting fixing member (12, 22).

3. Suspension device (10, 101, 102) according to any one of claims 1 or 2, intended for a two-wheeled vehicle (100) which comprises a chassis (1) having a flat portion (la) having, with reference to a rear / front direction (Fl) of the vehicle in the forward operating position, a rear end (1b) provided with a fork within which extends a part of the rear wheel (6) which comprises the axis of rotation (6a) and a peripheral rolling part (6b), the suspension device (10, 101, 102) being shaped so that in the operating position, the pivoting fixing member (12, 22) is fixed on the fork of the chassis (1), in a grip of the wheel, at the rear of the peripheral rolling part (6b) and at the front of the axis of rotation (6a) of the rear wheel (6), with reference to a direction (Fl) rear / front of the vehicle.

4. A suspension device (10, 101, 102) according to any one of claims 1 to 3, wherein the pivoting attachment member (12, 22) to the chassis (1), the rear wheel axle fixing member (13, 23) and the mechanical connection member (14, 24) form a triangle (T), seen laterally with respect to the rear / front direction (Fl) of the vehicle in the forward operating position, the mechanical connection member (14, 24) being arranged under the pivoting fixing member (12, 22) to the chassis (1) and the rear wheel axle fixing member (13, 23) (6).

5. Suspension device (10, 101, 102) according to any one of claims 1 to 4, wherein the swing arm (11) comprises at least one frame (11a) triangularly carrying the pivoting attachment member (12, 22) to the chassis (1), the rear wheel axle attachment member (13, 23) and the mechanical connection member (14, 24), the mechanical connection member (14, 24) being arranged under the pivoting attachment member (12, 22).

6. Suspension device (101) according to claim 5, in which the or each frame (11a) of the swing arm (11) comprises a suspension arm (11a1) carrying at a first end the pivoting fixing member (12) to the chassis (1), and at a second end the mechanical connection member (14), a plate (13a) carrying the rear wheel axle fixing member (13) being fixed to the suspension arm (11a1).

7. Suspension device (102) according to claim 5, in which the or each frame (11a) of the swing arm (11) comprises an L-shaped suspension arm (21al) carrying at a first end the pivoting fixing member (22) to the chassis (1), carrying at a second end the rear wheel axle fixing member (23) and carrying at a vertex of the L arranged between the first and second ends the mechanical connection member (24), and in which, with reference to the position of use, the mechanical connection member (24) is arranged under the pivoting fixing member (22).

8. Suspension device (10, 101, 102) according to any one of claims 1 to 7, in which the swing arm (11) comprises two frames (11a) intended to be arranged laterally and on either side of the rear wheel of the vehicle, each frame carrying a pivoting fixing member (12, 22) to the chassis (1), a rear wheel axle fixing member (13, 23) a mechanical connection member (14, 24), and in which, with reference to the position of use, the mechanical connection members (14, 24) are arranged under the pivoting fixing member (12, 22) to the chassis (1) and are each connected to a connecting rod (17), the connecting rods (17) being connected to the first end of the lever arm (18) by a common axis of rotation.

9. Suspension device (10, 101, 102) according to any one of claims 1 to 8, characterized in that it is shaped so that in the rest position in which the elastic suspension means (15) is not compressed, the pivoting attachment member (12, 22) to the chassis (1) is arranged above the or each rear wheel axle attachment member (13, 23), and so that in the activated position in which the elastic suspension means (15) is compressed, the pivoting attachment member (12, 22) to the chassis (1) is arranged below the or each rear wheel axle attachment member (13, 23).

10. Suspension device (10, 101, 102) according to the preceding claim, wherein, in the rest position, the pivoting fixing member (12, 22) and the or each rear wheel axle fixing member (13, 23) have a first height difference (dHl), and in the activated position the pivoting fixing member (12, 22) and the or each rear wheel axle fixing member (13, 23) have a second height difference (dH2), the first height difference (dHl) and the second height difference (dH2) being identical in absolute value.

11. Suspension device (10, 101, 102) according to any one of claims 1 to 10, wherein the swing arm (11) further comprises a fixing hoop (19) of a rear mudguard (20) arranged above the rear wheel (6).

12. Suspension device (10, 101, 102) according to any one of claims 1 to 11, characterized in that it is shaped so that in the position of use, the fixings of the lever arm (18) and of the elastic suspension means (15) are aligned in a median longitudinal plane (Pm) of the chassis (1) passing through a median plane of the front and rear wheels, such that the lever arm (18) and the elastic suspension means (15) are aligned in said median longitudinal plane of the chassis (1).

13. Suspension device (10, 101, 102) according to any one of claims 1 to 12, further comprising a protective casing covering at least the lever arm (18).

14. Suspension device (10, 101, 102) according to claim 13, wherein the casing also covers the elastic suspension means (15).

15. Scooter (100) characterized in that it comprises a suspension device (10, 101, 102) according to any one of claims 1 to 12, the scooter comprising a chassis (1) having a flat portion (la) having, with reference to the position of use, a rear end provided with a fork within which extends a part of a rear wheel (6) having an axis of rotation (6a), the suspension device (10, 101, 102) being arranged so that in the position of use: - the pivoting fixing member (12, 22) is fixed to the end of the fork of the chassis (1), to the rear of the peripheral rolling part and to the front of the axis of rotation of the wheel, with reference to a rear / front direction of the vehicle;and so that - the fixings of the lever arm (18) and the elastic suspension means (15) are aligned in a median longitudinal plane (Pm) of the chassis (1) passing through a median plane of the front and rear wheels, such that the lever arm (18) and the elastic suspension means (15) are aligned in said median longitudinal plane of the chassis (1).;

16. Scooter (100) according to claim 15, further comprising a footrest on either side of the lever and the elastic suspension means (15), and intended to receive the feet of a user (U) in use.

17. Scooter according to claim 15 or 16, further comprising a protective casing covering at least the lever arm (18).

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