Tilting suspension system, in particular for three-wheeled or multi-wheeled vehicles

Abstract

The invention relates to a steerable and tiltable suspension system (1) with mechanical support for a vehicle (2) comprising a frame (10) and three or more wheels, of which at least a first wheel (11) and a second wheel (12) are arranged on opposite sides of the vehicle (2), respectively, the suspension system (1) comprising a pair of hydraulic suspensions (40), and a second support arm (70) having a first end (40a) adapted to be hinged to the frame and a second end (40b) opposite the first end (40a) hinged to a respective support arm (70), each support arm (70) being configured to be hinged to the frame at the first end (70a) and to a respective support element (60) of the first wheel (11) and the second wheel (12) at a second end (70b) opposite the first end (70a). The suspension system (1) comprises at least one pair of elastic springs (30) configured to support respective support arms (70) to generate an elastic force opposite to gravity.

Description

Field of the Invention

[0001] The present invention relates to a steerable and tiltable suspension system with mechanical support, specifically for three - or multi - wheel vehicles, and more particularly to a hydraulic suspension system combined with a mechanical system. More specifically, the present invention relates to a motorcycle having at least three wheels, two of which are side - by - side and capable of tilting laterally due to the presence of a connection system between the two side - by - side wheels. Background Art

[0002] The vehicle refers to a vehicle having three or more wheels, such as a motorcycle, a tricycle, a quadricycle, and a scooter.

[0003] Three - wheel vehicles are currently known, where the two wheels at the front of the vehicle are steerable and swingable, and the rear wheel is a driving wheel, whose technical characteristics are similar to those of the rear wheel of a traditional two - wheel motorcycle or scooter. Quadricycles are also known, where the front part is similar to the above - mentioned three - wheel vehicle, and the rear part has a pair of swingable wheels.

[0004] It is well - known that vehicles with three or more wheels include a suspension system, which can be of mechanical or hydraulic type, where the latter, although more complex, is generally more efficient.

[0005] In a hydraulic suspension system for a vehicle with three or more wheels, particularly for a pair of wheels aligned on the same axis and swingable due to a pendulum system, for example, the hydraulic suspension system described in patent document WO 01 / 36253A1 can be mentioned. In this solution, a hydraulic connection is provided between two shock absorbers associated with a pair of wheels aligned on the same axis, and this hydraulic connection is capable of balancing the reciprocating movement of the wheels of the pair.

[0006] However, this solution is not without drawbacks, including the fact that, in the case where the vehicle is lifted off the ground, such as after a bump jump or even when the vehicle is lifted for repair purposes, the suspension system is lifted together with the frame, but the wheels and other swing components, as well as various arms and articulated rods, drop, resulting in a decrease in pressure (depression) in the hydraulic chambers, the oil, and the shock cylinders. However, such a pressure decrease is particularly harmful in the type of hydraulic system employed therein, because it may cause air to be contained in the oil, making the hydraulic suspension itself inefficient and / or inoperable.

[0007] Furthermore, after the hydraulic chambers of the shock absorbers enter a state of pressure decrease, when the vehicle comes back into contact with the ground, the pressure in the hydraulic chambers will increase, which may damage the suspension system itself. This is especially the case in the event of a jump due to a bump, and the subsequent collision with the ground will cause unwanted and often harmful pressure peaks.

[0008] Patent document EP 2046589 B1 aims to solve this technical problem by filling the lower chamber of the shock absorber cylinder with a pressurized gas (air, nitrogen, etc.). In this way, the pressure present in these chambers prevents the wheels and other oscillating components, as well as various arms and articulated rods, from descending, thereby preventing an unwanted pressure drop in the upper hydraulic chamber.

[0009] However, this solution is not without drawbacks. In particular, it has been found that the effect of the pressure present in the lower chamber of the hydraulic system causes an increase in friction due to the presence of the seals of the rods that must seal the system itself.

[0010] The friction introduced by this gas solution has a negative impact on the ride comfort of the suspension, thereby reducing the driving efficiency of the vehicle; most importantly, the friction at the first separation, which is referred to as "stick slip" in this document, causes significant problems and inconveniences even when driving the vehicle.

[0011] Furthermore, due to the leakage of air from the rods of the suspension, under pressure, the seal of the lower chamber guaranteed by the dynamic seal deteriorates physiologically over time. Therefore, pressure loss occurs over time, which in the long run leads to functional problems of the suspension itself. Therefore, it is necessary to plan control and recovery interventions for the vehicle during maintenance, which brings costs to the user. Summary of the Invention

[0012] In view of the above problems, the task of the present invention is to implement a steerable and tiltable suspension system with mechanical support, especially for three-wheel or multi-wheel vehicles, which overcomes the limitations of the prior art, thereby making the driving of the vehicle safer and more comfortable.

[0013] Within the scope of this task, the object of the present invention is to implement a suspension system that is robust and durable over time, in which the operating friction is reduced to a minimum and does not have a negative impact on the driving of the vehicle or its durability.

[0014] Another object of the present invention is to implement a suspension system that allows for a reduction in specific maintenance intervals, thereby also reducing the maintenance costs for the user.

[0015] Another object of the present invention lies in implementing a suspension system that can provide the widest possible guarantees of reliability and safety in use.

[0016] Another object of the present invention lies in implementing a suspension system that is easy to implement and economically competitive compared to the prior art.

[0017] The above task and the above objects, as well as other aspects that will become clearer later, are achieved by the suspension system according to claim 1.

[0018] Other features are provided in the dependent claims. BRIEF DESCRIPTION OF THE DRAWINGS

[0019] Further features and advantages of the present invention will become more apparent from the following exemplary but non - limiting description of preferred embodiments of the present invention with reference to the drawings, in which:

[0020] Figure 1 and Figure 1a shows a perspective view of a three - wheeled vehicle equipped with a suspension system according to the present invention;

[0021] Figure 2 shows Figure 1 the vehicle of in an inclined position relative to the vertical direction in a perspective view;

[0022] Figure 3 and Figure 3a shows Figure 1 the vehicle of in a front view without wheels;

[0023] Figure 4 shows a perspective view of a suspension system according to the present invention;

[0024] Figure 4a shows a front view of a suspension system according to the present invention, with details shown in cross - section;

[0025] Figure 5 and Figure 5a shows Figure 1 the vehicle of in an inclined position and without wheels in a front view;

[0026] Figure 6 shows a perspective view of some components of a suspension system according to the present invention;

[0027] Figure 7 and Figure 7a shows the assembly sequence of some components of a suspension system according to the present invention;

[0028] Figure 8 、 Figure 8a and Figure 8b shows the tension adjustment sequence of the spring former of a suspension system according to the present invention using a special tool;

[0029] Figure 9 shows Figure 8 、 Figure 8a and Figure 8b the special tool of in a perspective view;

[0030] Figure 10 and Figure 10a shows two different pre - loaded positions of the spring former of a suspension system according to the present invention;

[0031] Figure 11 and Figure 12 A first variant of the suspension system according to the invention is shown in two different operating configurations;

[0032] Figure 13 Show Figure 11 Details;

[0033] Figure 14 Showing the present invention Figure 11 and Figure 12 A pair of hydraulic suspensions of the suspension system are hydraulically connected to each other;

[0034] Figure 15 and Figure 16 Two different perspective views showing a second variant of the suspension system according to the invention;

[0035] Figure 17 A perspective view showing a third variant of the suspension system according to the present invention;

[0036] Figure 18 and Figure 19 Show Figure 17 Two different perspective views of the mid-suspension system with various components removed. DETAILED DESCRIPTION

[0037] With particular reference to the drawings, a steerable and tiltable suspension system with mechanical support is generally indicated by reference numeral 1. This suspension system is suitable for a vehicle 2 comprising a frame 10 and three or more wheels, wherein at least a first wheel 11 and a second wheel 12 are respectively arranged on opposite sides of the vehicle 2 itself.

[0038] Vehicle 2 can be, for example, a swinging three-wheeled vehicle with an endothermic engine or an electric device. Perhaps, vehicle 2 can also be a four-wheeled vehicle, in any case a swinging type.

[0039] The two wheels 11 and 12 located on the sides of the vehicle 2 may also be offset from each other.

[0040] According to the embodiment shown in the figures, the vehicle 2 is a three-wheeled vehicle, wherein the steerable, pivoting wheels are two front wheels 11 and 12, which are coupled to the same axle (front axle).

[0041] The vehicle 2 is further provided with a steering device 20 acting on a steering arm 80 .

[0042] The suspension system 1 comprises a pair of hydraulic suspensions 40 having a first end 40 a adapted to be articulated to the frame 10 of the vehicle 2 and a second end 40 b opposite the first end 40 a and articulated to a respective support arm 70 .

[0043] Each support arm 70 is further configured such that a first end 70a thereof is hinged to the vehicle frame 10 of the vehicle 2, and a second end 70b opposite to the first end 70a is hinged to a respective support element 60 of the first wheel 11 and the second wheel 12, wherein the support element 60 may be a mechanical spider, and a spindle 50 for supporting the hubs of the wheels 11, 12 is constrained to the mechanical spider.

[0044] According to the present invention, the suspension system 1 includes at least a pair of elastic springs 30, and each elastic spring 30 is configured to support a respective support arm 70 and generate an elastic force opposite to gravity.

[0045] Advantageously, the elastic springs 30 provide an upward thrust to all components of the vehicle 2 fixed to the support arm 70, that is, first, provide an upward thrust to the hydraulic suspension 40, and also provide an upward thrust to the mechanical spider 60 and the spindle 50. The spindle 50 supports the wheels 11 and 12, and ultimately also supports the wheels 11 and 12 themselves with associated hubs and brakes.

[0046] Each elastic spring 30 is preferably configured to act between the vehicle frame 10 of the vehicle 2 and the support arm 70.

[0047] Preferably, each elastic spring 30 is preloaded so as to generate an upward thrust on the entire suspension system 1, and thus can support the weight of all components connected to the support arm 70 and the hydraulic suspension 40, especially when the vehicle 2 is lifted off the ground.

[0048] Preferably, each elastic spring 30 is a torsion spring.

[0049] Preferably, the axis of the elastic torsion spring 30 is parallel to the axis of rotation of the respective support arm 70 relative to the vehicle frame 10.

[0050] More preferably, the elastic torsion spring 30 has a torsion axis coaxial with the axis of rotation of the respective support arm 70.

[0051] Even more preferably, the elastic torsion spring 30 includes a first end 30a and a second end 30b. The first end 30a is configured to be attached to the vehicle frame 10 of the vehicle 2, and the second end 30b opposite to the first end 30a is adapted to support and push the respective support arm 70.

[0052] Advantageously, each elastic torsion spring 30 is assembled on a respective bushing 73, and the bushing 73 is further assembled on a hinge element of the support arm 70 and the vehicle frame 10 of the vehicle 2.

[0053] Preferably, the elastic spring 30 is assembled on a respective bushing at a portion presenting the coil of the elastic spring 30 itself.

[0054] Preferably, the hinge element includes a screw 71 and a nut 72. The nut 72 can be screwed onto the end of the screw 71 such that the screw 71 can be fixed to the vehicle frame 10 and serves as the hinge of the support arm 70. Preferably, as shown in the drawings, a bushing 73 can be fitted onto the screw 71, preferably at its head end 71a and / or on the nut 72.

[0055] As shown in the drawings, the screw 71 includes a head end 71a which can advantageously have a faceted portion, such as a hexagonal shape for example. The nut 72 can also have an end 72a which has a faceted portion, such as a hexagonal shape for example. Such faceted portions of hexagon shape facilitate clamping and screwing by means of, for example, a suitable wrench.

[0056] Preferably, the suspension system 1 includes two pairs of elastic springs 30 which are symmetrically positioned in the front and rear regions of the vehicle frame 10 relative to the corresponding support arms 70 respectively. In this way, the elastic springs 30 provide a uniformly distributed support for the support arms 70 in the front - rear direction.

[0057] As Figures 1 to 9 shown, the elastic springs 30 engage with the vehicle frame 10 and the support arms 70 at an external position relative to the support arms 70 themselves. In Figure 15 、 Figure 16 and Figures 17 - 19 ,two variants of the suspension system 1 are shown, in which the elastic springs 30 engage with the vehicle frame 10 and the support arms 70 at an internal position relative to the support arms 70 themselves. In fact, the support arms 70 can have a symmetrical configuration defined by a pair of arm elements 79 which face each other and are preferably rigidly associated with each other. Thus, as Figure 15 、 Figure 16 and Figures 17 - 19 shown, the elastic springs 30 can thus advantageously be arranged between the pair of arm elements 79, at an internal position relative to the support arms 70 themselves, and are advantageously better protected.

[0058] In a second variant of the suspension system 1, as Figure 15 and Figure 16 shown, the elastic torsion springs 30 are fitted onto corresponding bushings 73 which are in turn fitted onto the hinge elements of the support arms 70 and the vehicle frame 10 of the vehicle 2. However, the hinge elements project towards the inside of the two arm elements 79.

[0059] Preferably, according to as Figure 15 and Figure 16Second variant of the suspension system 1 shown, each resilient spring 30 comprising a pair of first ends 30a and a second end 30b, said pair of first ends 30a being configured to be attached to the vehicle frame 10 of the vehicle 2, said second end 30b being opposite to said first ends 30a and being adapted to support and push the respective support arm 70. Preferably, in fact, each resilient spring 30 comprises two coiled portions which are joined together at an extended spring section 33, defining the second end portion 30b, i.e., the end portion which supports and pushes the respective support arm 70.

[0060] In a third variant of the suspension system 1, as Figures 17 - 19 shown, the suspension system 1 comprises a pair of resilient springs 30 which are also of the torsion type.

[0061] Each spring 30 comprises a first end 30a and a second end 30b, said first end 30a being configured to be attached to the vehicle frame 10 of the vehicle 2, said second end 30b being opposite to said first ends 30a and being adapted to support and push the respective support arm 70.

[0062] Preferably, each spring 30 is associated with the vehicle frame 10 and the respective support arm 70 only through its two ends 30a, 30b, i.e., there are no other support and / or guiding means. In other words, Figures 17 - 19 the variant shown in does not include any bushings which rotatably support at least the coiled portions of the spring 30 itself.

[0063] Preferably, as Figures 17 - 19 shown, the first end 30a of the resilient spring 30 is fixed to the support arm 70 by a plate 34 which can be threadedly connected to the support arm 70 by a pair of screws 35. Preferably, the second end 30b is fixed to a support body 36 of the spring 30 which is associated with the vehicle frame 10 of the vehicle 2. Preferably, a plate 37 is provided which can be threadedly connected to the support body 36 of the spring 30 by screws 38, said plate being configured to fasten the end 30b of the spring 30 to the support body 36 itself.

[0064] Preferably, as Figure 18 shown, the support body 36 of the spring 30 is rigidly constrained to the vehicle frame 10 by a bracket 39.

[0065] Advantageously, there are no restraint elements for the resilient spring 30, in particular no bushings 73 within its coiled portions, allowing the spring 30 to twist freely in the space between the arm elements 79 without friction with such bushings.

[0066] With particular reference to Figure 4 and Figure 4a, each hydraulic suspension 40 includes at least one rod-piston assembly 44 inside it. The hydraulic suspensions 40 on both sides of the vehicle 2 are in fluid communication with each other via a three-way valve 42 through a flexible fitting 47, where the third passage of the valve 42 is in fluid communication with a pressurized tank 41 responsible for the system suspension.

[0067] In particular, a piston 43 configured to separate the pressurized gas present in the first chamber 46 from the oil present in the second chamber 49 moves in the pressurized tank 41, where the oil present in the second chamber 49 of the pressurized tank 41 is in fluid communication with the interior of the valve 42 and is in fluid communication with the oil chamber 45 of the hydraulic suspension 40 through the flexible fitting 47. The second chamber 49 of the pressurized tank 41 defines a variable volume. In addition, a spring 48 is configured to progressively manage the bending descent of the vehicle 2 until the maximum bending angle, as Figure 2 , Figure 5 and Figure 5a shown.

[0068] In the use of this configuration of the suspension system 1, due to the relative displacement of the oil from one side to the other side of the hydraulic suspension 40, the upward movement of the wheel 11 of the vehicle 2 causes the downward movement of the wheel 12, and vice versa, and the two sides of the hydraulic suspension 40 are in fluid communication with each other through the flexible fitting 47 and the valve 42.

[0069] In another configuration, at rest, the valve 42 is adapted to block the passage of oil between the hydraulic suspensions 40, thereby preventing the relative upward and downward movement of the wheels 11 and 12 of the vehicle 2. This prevention is useful when parking the vehicle 2, because by closing the valve 42, the stability of the vehicle 2 can be ensured, thus allowing the cancellation of the traditional supports for parking the vehicle 2 in a balanced manner.

[0070] Advantageously, the elastic torsion spring 30, which is appropriately preloaded and connected between the frame 10 and the support arm 70, is configured to generate pressure in the oil chamber 45 of the hydraulic suspension 40, so that when the vehicle 2 is lifted from the road surface, for example, in the presence of jumps, bumps or for maintenance needs, when the suspension system 1 has an upward movement relative to the wheels 11, 12, the arm 70 and other swing components, the pressure drop in the chamber 45 is prevented. As described above, this ensures the avoidance of air being entrained in the oil of the suspension system 1, for example, through the chamber 46 and the piston 43. This air entrainment is actually undesirable because it makes the suspension system 1 inefficient and / or unavailable.

[0071] In addition, the presence of this counter-pressure exerted by the torsion spring 30 under all operating conditions of the vehicle 2 minimizes the friction generated in the hydraulic part of the suspension system 1, thereby reducing the construction cost and, most importantly, the maintenance cost.

[0072] Preferably, the resilient spring 30 can be attached to the vehicle frame 10 at a plurality of attachment points 31, 31' of its first end 30a to the vehicle frame 10, so that by selecting different attachment points 31 or 31', the preload of the resilient spring 30 can be changed, enabling the same suspension system 1 to be used for vehicles 2 with different track widths, such as vehicles with a wider track width and a greater unsprung mass.

[0073] Advantageously, the resilient spring 30 can also be of the tension or compression type, acting between the vehicle frame 10 and the support arm 70, or still consist of a system combined by several springs.

[0074] Figures 11 to 14 A variant of the suspension system 1, in particular a hydraulic suspension 40, is shown. According to this variant, each hydraulic suspension 40 includes a rod-piston assembly 44 axially movable within a cylinder 400. The piston 44a of the rod-piston assembly 44 divides the cylinder 400 into an upper chamber 401 and a lower chamber 402 respectively. The cylinder 400 is closed at the bottom by a lower cover 104 provided with a seal 107. The rod 44b of the rod-piston assembly 44 slides axially relative to this seal 107, which advantageously ensures the sealing of the lower chamber 402.

[0075] The rod 44b of the rod-piston assembly 44 has a conduit 103 extending along the longitudinal extension direction of the rod 44b itself inside, and the conduit 103 is configured to fluidly connect the internal volume of the cylinder 400 with the external environment outside the cylinder 400. In particular, the conduit 103 is configured to fluidly connect the internal volume of the lower chamber 402 of the cylinder 400 with the external environment.

[0076] Preferably, the rod 44b further includes at least one transverse hole 102, and the at least one transverse hole 102 is configured to fluidly connect the conduit 103 with the lower chamber 402 of the cylinder 400.

[0077] Therefore, the at least one transverse hole 102 is formed in the rod portion 44b such that the transverse hole 102 is always inside the cylinder 400 when the rod-piston assembly 44 is in any position relative to the cylinder 400. As Figures 11 to 14 shown, for example, the transverse hole 102 is formed in the rod 44b, close to the piston 44a. Thus, even in the case where the rod-piston assembly 44 extends maximally from the cylinder 400, as Figure 12 shown, the transverse hole 102 remains in the lower chamber 402 of the cylinder 400.

[0078] Preferably, the rod 44b further includes a one-way valve 101, and the one-way valve 101 is configured to fluidly connect the conduit 103 with the external environment.

[0079] Therefore, the one-way valve 101 is made of the rod portion 44b such that at each position of the rod-piston assembly 44 relative to the cylinder 400, the one-way valve 101 is always outside the cylinder 400. For example, as Figures 11 to 14 shown, the one-way valve 101 is located in the rod 44b, near its end 40b. Thus, even when the rod-piston assembly 44 is fully retracted in the cylinder 400, as Figure 11 shown, the one-way valve 101 remains outside the cylinder 400, facing the external environment.

[0080] Therefore, basically, the internal volume of the lower chamber 402 of the cylinder 400 can be fluidly connected to the environment outside the cylinder 400 through the at least one lateral hole 102, the conduit 103, and the one-way valve 101.

[0081] The downward movement of the rod 44b allows the air present in the lower chamber 402 of the cylinder 400 to be discharged successively through the lateral hole 102, the longitudinal conduit 103, and the one-way valve 101, which allows the air to pass only in the discharge direction.

[0082] When the rod 44b moves upward in the opposite direction, due to the presence of the one-way valve 101, air is not allowed to enter the conduit 103. This prevents dirt or other external substances from being able to penetrate the volume inside the lower chamber 402 of the cylinder 400.

[0083] Similarly, the presence of the seal 107 also prevents dirt or other external substances from entering the lower chamber 402 of the cylinder 400.

[0084] Furthermore, since the fluid present in the lower chamber 402 of the cylinder 400 is not affected by high pressure, and even the seal 107 itself is not affected by the stress from high pressure, the good operation of the hydraulic suspension 40 is not significantly interrupted by the friction at the sliding area of the rod 44b relative to the seal 107.

[0085] Preferably, there is a sufficient amount of oil in the lower chamber 402 of the cylinder 400 to keep the sliding surfaces of the seal 107 and the rod 44b themselves lubricated.

[0086] Preferably, as Figure 12 shown, the at least one lateral hole 102 is formed at a certain height along the rod 44b such that in the case of the maximum extension of the hydraulic suspension 40, the lateral hole 102 is at the minimum distance from the bottom of the cylinder 400, i.e., from the lower cover 104.

[0087] In this way, the amount of oil present in the lower chamber 402 of the cylinder 400 does not escape through the lateral hole 102 and the conduit 103 leading to the one-way valve 101 because even in the case of the maximum extension of the suspension 40, the hole 102 remains at a level higher than the level of the oil present in the lower chamber 402.

[0088] Each hydraulic suspension 40 may include a respective one-way valve 101.

[0089] Alternatively, as Figure 14 shown, a pair of hydraulic suspensions 40 may include a single one-way valve 101 which is applied to a conduit 103 of a rod 44b of a rod-piston group 44 of a first hydraulic suspension 40. A conduit 103 of a rod 44b of a rod-piston group 44 of a second hydraulic suspension 40 is in fluid communication with the conduit 103 of the first hydraulic suspension 40 via another conduit 109. This another conduit 109 may advantageously be constituted by a hose.

[0090] According to the above Figure 14 variant, the operation of the suspension system 1 having a single one-way valve 101 is similar to the operation described above with reference to the embodiment in which each hydraulic suspension 40 has only one one-way valve 101.

[0091] Furthermore, the present invention also relates to a method for preloading an elastic spring 30, the method comprising the following steps:

[0092] a. Having the suspension system 1 as described above;

[0093] b. Having a dedicated wrench 90 for preloading, the wrench 90 including a grip rod 91, an end portion 92 which can be assembled around the elastic spring 30, and a protrusion 93 which is configured to engage with a first end 30a of the elastic spring 30;

[0094] c. Positioning the end portion 92 of the dedicated wrench 90 around the elastic spring 30;

[0095] d. Rotating the dedicated wrench 90 so that the first end 30a of the elastic spring 30 is at one of the attachment points 31, 31' on the vehicle frame 10 selected according to the required preloading degree;

[0096] e. Removing the dedicated wrench 90 from the elastic spring 30.

[0097] In this way, the elastic spring 30 is properly loaded and attached to the vehicle frame 10.

[0098] More specifically, the end portion 92 of the dedicated preloading wrench 90 is defined by a hollow structure which is adapted to surround the elastic spring 30, in particular the helix of the elastic spring 30, at a hinge element (i.e., screw 71) of the support arm 70 and the vehicle frame 10. At this position, the protrusion 93, preferably obtained at the above hollow structure, engages with the first end 30a of the elastic spring 30 so as to rotate it around the hinge element.

[0099] Thus, the rotation of the special wrench 90 winds the elastic spring 30 around the hinge element, loading itself until it reaches one of the points 31, 31' where the first end 30a of the spring 30 is attached to the vehicle frame 10.

[0100] The fact that a plurality of attachment points 31, 31' are arranged at different angular distances on the vehicle frame 10 allows the first end 30a of the spring 30 to be attached to different positions, with different degrees of preloading of the elastic spring 30 itself corresponding to said different positions. Figure 10 and Figure 10a Two different spring preloading configurations 30 are respectively shown in Figure 10 In the configuration of Figure 10a the end 30a of the spring 30 is fixed to the first attachment point 31, while in Figure 10a the end 30a of the spring 30 is fixed to the second attachment point 31', and the second attachment point 31' is angularly spaced from the first attachment point 31 by approximately 90°.

[0101] In practice, it has been found how the suspension system according to the present invention achieves the tasks and the intended purposes, as it allows for a safer and more comfortable driving of the vehicle.

[0102] According to the present invention, another advantage of the suspension system is that it avoids air entrainment in the oil and reduces the friction inside the chambers of the hydraulic suspension system, thus improving the efficiency of the system and greatly reducing the maintenance phase.

[0103] Furthermore, all details can be replaced with other technically equivalent elements. In practice, any material can be used according to requirements, as long as they are compatible with the specific use, dimensions and possible shape.

Claims

1. A steerable and tiltable suspension system (1) with mechanical support for a vehicle (2), the vehicle (2) comprising a frame (10) and three or more wheels, wherein at least a first wheel (11) and a second wheel (12) are respectively arranged on opposite sides of the vehicle (2), the suspension system (1) comprising a pair of hydraulic suspensions (40), the hydraulic suspensions (40) having a first end (40a) adapted to be hinged to the frame (10) and a second end (40b) opposite the first end (40a) hinged to a respective support arm (70), each support arm (70) being configured to be hinged at a first end (70a) to the frame (10) and at a second end (70b) opposite the first end (70a) to a respective support element (60) of the first wheel (11) and the second wheel (12), characterized in that, The suspension system (1) includes at least a pair of elastic springs (30), and each elastic spring (30) is configured to support a corresponding support arm (70) to generate an elastic force opposite to gravity.

2. The suspension system (1) according to claim 1, wherein, Each elastic spring (30) is configured to operate between the vehicle frame (10) and the support arm (70).

3. The suspension system (1) according to claim 1 or 2, wherein, Each elastic spring (30) is preloaded.

4. The suspension system (1) according to any one of the preceding claims, wherein, Each elastic spring (30) is a torsion spring, and its axis is parallel to, preferably coaxial with, the axis of rotation of the corresponding support arm (70) around the vehicle frame (10).

5. The suspension system (1) according to any one of the preceding claims, wherein, Each elastic spring (30) is a torsion spring, and the torsion spring includes a first end (30a) configured to be attached to the vehicle frame (10) and a second end (30b) opposite to the first end (30a) and adapted to support and push the corresponding support arm (70).

6. The suspension system (1) according to any one of the preceding claims, wherein, Each elastic spring (30) is assembled on a corresponding bushing (73), and the bushing (73) is assembled on a hinge element of the support arm (70) and the vehicle frame (10).

7. The suspension system (1) according to claim 6, wherein, The hinge element includes a screw (71) and a nut (72) that can be screwed onto the screw (71), and the bushing (73) is assembled on the screw (71) and / or the screwable nut (72).

8. The suspension system (1) according to any one of the preceding claims, including a pair of elastic springs (30), and the elastic springs are symmetrically positioned in the front and rear regions of the vehicle frame (10) relative to the corresponding support arms (70) respectively.

9. The suspension system (1) according to any one of the preceding claims, wherein, The first end (30a) of each elastic spring (30) is configured to be engageable with a plurality of attachment points (31) on the vehicle frame (10) so as to change the preloading of each elastic spring.

10. The suspension system (1) according to any one of the preceding claims, wherein, Each of the hydraulic suspensions (40) includes a rod-piston assembly (44) axially movable in a cylinder (400), and the rod (44b) of the rod-piston assembly (44) includes a conduit (103) that extends in the rod (44b) along the longitudinal extension direction of the rod (44b), and the conduit (103) is configured to put the internal volume of the cylinder (400) into fluid communication with the environment outside the cylinder (400).

11. The suspension system (1) according to claim 10, wherein, The rod (44b) includes at least one transverse hole (102), and the at least one transverse hole (102) is configured to put the conduit (103) into fluid communication with the chamber (402) of the cylinder (400).

12. The suspension system (1) according to claim 10 or 11, wherein The rod (44b) includes a one-way valve (101), and the one-way valve (101) is configured to put the conduit (103) into fluid communication with the environment outside the cylinder (400).

13. The suspension system (1) according to claim 12, wherein, The pair of hydraulic suspensions (40) includes a single one-way valve (101) and another conduit (109), the single one-way valve (101) being configured to place the conduit (103) of the first rod (44b) of the rod-piston assembly (44) of the first hydraulic suspension (40) in fluid communication with the ambient fluid outside the cylinder (400) of the first hydraulic suspension (40), and the other conduit (109) being configured to place the conduit (103) of the first rod (44b) of the first hydraulic suspension (40) in fluid communication with the conduit (103) of the second rod (44b) of the second hydraulic suspension (40).

14. The suspension system (1) according to claim 1, 2 or 3, wherein, Each resilient spring (30) is a tension spring or a compression spring acting between the vehicle frame (10) and the support arm (70).

15. A method for preloading a resilient spring (30) of a suspension system (1) according to any one of claims 1 to 13, the method comprising the steps of: a. having a suspension system (1) according to any one of claims 1 to 13; b. having a dedicated wrench (90) for preloading, the dedicated wrench (90) including a grip bar (91), an end (92) that can be fitted around the resilient spring (30), and a protrusion (93) configured to engage with the first end (30a) of the resilient spring (30); c. positioning the end (92) of the dedicated wrench (90) around the resilient spring (30); d. rotating the dedicated wrench (90) so that the first end (30a) of the resilient spring (30) is at one of the attachment points (31) on the vehicle frame (10) selected according to the desired degree of preloading; e. removing the dedicated wrench (90) from the resilient spring (30) so that the resilient spring (30) is properly loaded and engaged with the vehicle frame (10).

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