Control system of the trim of vehicles with more than two wheels

Abstract

The present invention relates to an improved control system of the trim of motorcycles with more than two wheels. More in particular, it relates to motorcycles which have at least three wheels and can lean sideways by virtue of the presence of a so-called wheel tilting system. The present invention improves on prior art HTS hydro-pneumatic systems, to improve the vehicle trim, particularly while cornering with the leaned vehicle.

Claims

1. A hydro-pneumatic tilting system of a vehicle with more than two wheels, said vehicle having at least two wheels tilting by means of said hydro-pneumatic system, the system comprising at least one first hydraulic cylinder and a second hydraulic cylinder each associated to a respective tilting wheel of the vehicle, said at least one first hydraulic cylinder and second hydraulic cylinder respectively comprising first and second upper chambers containing oil, and first and second lower chambers containing pressurized gas, the system being characterized in that the system comprises second connection means which puts said first lower chamber and said second lower chamber into fluid communication, so that said gas may flow from one cylinder to the other cylinder.

2. The tilting system according to claim 1, characterized in that said second connection means comprises shut-off means adapted to adjust the gas flow which transits from one cylinder to the other cylinder by means of said second connection means.

3. The tilting system according to claim 2, characterized in that said second connection means comprises a pipe.

4. The tilting system according to claim 2, characterized in that said shut-off means comprises a mechanically or electrically actuated valve.

5. The tilting system according to claim 4, characterized in that said valve is configured to be controlled by a driver by means of a manual actuating system.

6. The tilting system according to claim 4, characterized in that said valve is automatically controlled by an electronic control unit.

7. The tilting system according to claim 6, characterized in that said electronic control unit further comprises a vehicle trim control system, which controls switching of said valve from an open position to a closed position.

8. The tilting system according to claim 7, further comprising a leaning sensor adapted to send an enable signal for closing a shut-off valve to said electronic control unit.

9. The tilting system according to claim 7, further comprising a sensor adapted to detect extension of to rods of said first and second cylinders and to send an enable signal for closing a shut-off valve to said electronic control unit.

10. The tilting system according to claim 2, characterized in that said shut-off means comprises a proportioning valve.

11. A tilting system according to claim 2, characterized in that said shut-off means comprises an on-off valve.

Description

BRIEF DESCRIPTION OF DRAWINGS

(1) Further objects and advantages of the present invention will be apparent in the detailed description of an embodiment shown by way of non-limiting example in the accompanying FIG. 1, which shows an overview of the improved hydro-pneumatic tilting system of a vehicle with more than two wheels according to the present invention.

DESCRIPTION OF THE PREFERRED EMBODIMENT

(2) The improved hydro-pneumatic tilting system of a vehicle with more than two wheels according to the present invention comprises at least one first hydraulic cylinder 10 and one second hydraulic cylinder 20 arranged in fluid communication by means of first hydraulic connection means 23.

(3) Said first hydraulic connection means 23 may advantageously consist of a conduit, more preferably a pipe, which puts into hydraulic communication, in particular, the first 10a and second 20a upper chamber of said first 10 and second 20 hydraulic cylinder, respectively, in which oil is contained, as known from the tilting system HTS developed by the Applicant. The first 10b and second 20b lower chamber of said first 10 and second 20 hydraulic cylinder, respectively, contain pressurized gas.

(4) When the vehicle leans, the piston corresponding to the wheel inside the curve, for example the first piston 100 associated with said first cylinder 10, pushes the oil contained in the first upper chamber 10a of the cylinder itself into the second upper chamber 20a of the opposite cylinder, in this case the second cylinder 20 by means of the first connection pipe 23, thus moving the two wheels connected to the first 100 and second 200 piston in opposite directions.

(5) An accumulator 24, with an end part hydraulically connected to the connection pipe 23 may be present. A rotary piston (or septums or baffles) is present in the accumulator 24 which forms a chamber that contains a pressurized gas, having a spring function. In case of rough terrain, which may cause a sudden movement of a single wheel, the movement of the fluid is partially damped by the accumulator, without immediately flowing towards the other wheel causing its immediate movement.

(6) A pressurized gas is present in the system which fills the lower part of the cylinders. This solution maintains circuit functionality by introducing two important features: when the leaning angle increases, the available space for the gas contained in the cylinder outside the corner decreases and its pressure increases, thus increasing the resistance of the system to further increase the leaning angle. This is very effective to help the driver feel the angle at which leaning starts to become dangerous because the grip limit of the tires is about to be reached.

(7) Another advantage is the straightening effect imparted by the pressurized gas: by virtue of the presence of the pressurized gas in the lower chamber located on the side of the vehicle outside the curve, when the driver needs to straighten the vehicle out of curve or must rapidly change direction by rapidly inclining the vehicle on the opposite side, for example to run on a series of curves and counter-curves, the vehicle straightens very rapidly and effortlessly for the driver.

(8) However, it is precisely the presence of the pressurized gas in the lower chamber of the cylinder which is compressed in the cylinder on the outside of the curve when cornering that determines an undesired effect in case of rough terrain.

(9) Indeed, in the case of rough terrain tackled transversely, which causes a compression in the cylinder upstream of the inclined plane, for example the first cylinder 10, the oil present in the first upper cylinder 10a of said first cylinder 10 transits through said first hydraulic connection pipe 23 towards the second upper chamber 20a of said second cylinder 20, thus causing a further compression of the gas present in the second lower chamber 20b of said second cylinder 20. Said further compression of the gas causes a lateral thrust which may destabilize the vertical trim of the vehicle.

(10) Similarly, a deep hole or large pothole may have a negative effect on the vehicle trim, again because of the compressed gas in the lower part of the cylinders both on a straight line and on corners.

(11) However, also in absence of roughness, it may be desirable for the driver to either reduce or entirely eliminate the straightening effect caused by the pressurized gas in the cylinder on the outside of the corner. For example, if the driver wants to lean the vehicle at accentuated angles at higher speed (a prerogative of track racing driving) without feeling front end resistance caused, also in this case, by the presence of pressurized gas in the lower part of the external cylinder.

(12) The hydro-pneumatic tilting system according to the present invention allows to solve these drawbacks by virtue of the fact of comprising further second connection means 40 which put the first 10b and the second 20b lower chamber of said first 10 and second 20 cylinder into fluid communication, further gas shut-off means 50 being provided on said second connection means 40.

(13) Said second hydraulic connection means preferably consist of a rigid pipe or a flexible hose.

(14) Said shut-off means 50 adjust the gas flow through said second connection means 40 by either separating or putting into fluid communication the two lower chambers 10b and 20b of said cylinders.

(15) Said shut-off means 50 preferably consist of a valve, which can be actuated by the driver, for example by means of a button or a lever type control or which can be actuated by a control unit which processes different indicative signals of the trim and of the dynamic conditions of the vehicle in all instants.

(16) Such a valve may be electrically actuated by a solenoid or stepper motor.

(17) When the shut-off means 50 are controlled by the driver, the driver may choose the best trim configuration as a function of the type of path.

(18) The operation of the system is as follows.

(19) When the shut-off means 50 are closed, the improved hydro-pneumatic system according to the present invention behaves like the traditional system, in which the lower chambers 10b, 20b of the cylinders which contain gas are separated from each other and the gas present in a cylinder is compressed as the volume of the chamber in which is contained decreases, thus determining the straightening thrust of the hydro-pneumatic tilting system free from the second connection means 40.

(20) When shut-off means 50 are open, the gas may freely transit from one cylinder to the other, in particular from a lower chamber 10b, 20b to the other by means of said second connection means 40.

(21) Thus, in this configuration of the system, when the vehicle is leaning when cornering, the gas contained in the lower chamber of the cylinder outside the curve, instead of being compressed inside the chamber itself, may flow towards the chamber of the opposite cylinder. If the shut-off means are entirely open, the gas will flow completely from one chamber to the other pushed by the movement of the pistons either completely canceling out or in any case drastically limiting the straightening effect because there will be no difference of pressure in the lower chambers of the cylinders.

(22) By operating on the valve, either the driver or the electronic control system of the vehicle may advantageously opt for intermediate configurations so as to decrease, but not completely cancel out, the compression of the gas and thus the respective difference of pressure in the lower chambers of the cylinders, so as not to completely cancel out the consequent straightening effect.

(23) Given the description of the system, it is worth noting that the driver may take the shut-off valve 50 instant by instant, at their discretion, from the closed position to the open position, also when fully cornering, or the valve may be advantageously opened by an electronic control unit according to the dynamic parameters of the vehicle, such as speed, centrifuge acceleration, sudden tilting of the wheels caused by potholes in the ground and so on, while care must be adopted when passing from the open position to the closed position of the shut-off valve 50, because the valve must be closed with the volume of the lower cylinders being in equal condition, the pressure conditions in the chambers being equal.

(24) The condition of equality of the volumes of the chambers is obtained when the tilting system is aligned, i.e. when the vehicle is not leaning.

(25) Thus, by way of example, the shut-off valve 50 may be closed with the vehicle stopped on flat surface, better if with the vehicle on the central stand.

(26) In all cases, the tilting system according to the present invention may advantageously equip a vehicle trim control system which enables the closing of the shut-off valve 50. Said vehicle trim control system may comprise a leaning sensor or a sensor able of measuring the extension of the rods of said first 100 and second 200 piston, or means able of detecting the inclination of the suspension arms, or other similar means able of detecting the condition of tilting system aligned corresponding to the equality of the volumes of said lower chambers 10b, 20b.

(27) For example, in the condition of vehicle supported by the central stand on flat surface, the volumes of the lower chambers 10b, 20b of said first 10 and second 20 cylinder of the hydro-pneumatic system according to the present invention are equal and the gas volume is distributed equally in the two chambers, this condition being essential for the correct operation of the tilting system.

(28) Many changes, modifications, variations and other uses and applications of the subject invention will be apparent to a person skilled in the art after having considered the description and the accompanying drawings which illustrate preferred embodiments thereof. Such changes, modifications, variations and other uses and applications which do not differ from the scope of the invention as defined in the appended claims and form an integral part of the text are covered by the present invention.