NL9401303A - Self-stabilizing, steerable vehicle with at least three wheels - Google Patents

Abstract

Self-balancing vehicle with at least three wheels which are supported on the ground, at least two of which are arranged on either side of the centre of gravity, in relation to the longitudinal axis of the vehicle, and at least one of which is steerable, and at least part of the vehicle can tilt about the longitudinal axis of the vehicle, and a sensor is coupled to a steering member for steering the at least one steerable wheel, in order to measure the level and/or direction of the load, in order to cause and/or maintain a change in direction of the steerable wheel while travelling and/or the magnitude and/or direction of a change in direction of the steerable wheel while travelling, and an energized tilting element is provided, for the purpose of tilting the said vehicle part about the longitudinal axis of the vehicle, which tilting element is coupled to the sensor, in order to cause tilting according to what the sensor records.

Description

Self-stabilizing, direction-controlled vehicle with at least three wheels.

The invention relates to self-stabilizing, direction-controlled vehicles. In particular, the invention relates to vehicles which allow tilting of at least one vehicle part relative to the vehicle longitudinal axle. This makes it possible to tilt the vehicle wholly or partly towards the inside of the bend when driving a bend.

A known vehicle of the above-mentioned type is described in GB-A-2225990. This known vehicle is a tricycle, the seating area for the driver, together with the single, central front wheel, can be tilted relative to the transverse axle to which the rear wheels arranged on either side of the vehicle longitudinal axle are attached. It has been described that the tilting can be achieved by changing the load distribution in the tilting part of the vehicle, or by using hydraulic or mechanical elements. No system has been described for the efficient tilting of the vehicle part depending on the driving conditions, such as the bend radius, the slope of the road surface, the load and / or speed of the vehicle, and so on. Nor has it been described that the single front wheel is steerable in the direction.

The object of the invention is to provide a control system with which the tilting of the vehicle or vehicle part towards the inside of the bend can be effectively achieved, so that under all driving conditions, in particular at speeds higher than those which are usual during parking and parking of the vehicle , good stability can be guaranteed.

To this end, according to the present invention, measurement of the force / torque or the size of the steering angle takes place in order to obtain a change of direction of the or the directionally controllable wheel (s), which data are used for determining the size and direction of tilting for the tilting vehicle part. Preferably, the steering force / torque is measured since it has been found that these load quantities provide the best results. Such force / torque develops automatically when the directional steering wheel has a certain run-out, while the tilt angle does not correspond to the driving speed and the turn radius intended by the steering wheel rotation. Using this insight, the degree of tilt can be controlled by measuring the intended force / torque.

Compared to, for example, the known use of acceleration sensors, the present invention provides a particularly natural and direct driving behavior, so that the vehicle can also be operated by untrained persons.

The use of a tiltable directional steering wheel is preferred, with which a particularly simple control system can be used. This makes it fairly easy to achieve the balance for each tilt position, since the steering load will then be zero or almost zero in any balance position for the tilt movement. Thus, when initiating a turn in connection with a tiltable directional steering wheel, the steering load will initially be greatest, to gradually decrease as the tilted equilibrium position approaches as the vehicle follows the desired turn. It will be clear that, by properly dimensioning the control system, the time lag between the initiation of the bend and the reaching of the tilted equilibrium position can be small, thus achieving a behavior that corresponds to the cornering behavior of the modern motorcycle.

A position sensor can be included in the control circuit to make the tilting speed proportional to the steering angle, for example.

For example, the tilting speed is smaller as the inclination relative to. the vertical is larger. In addition, it provides a steering force variation that is proportional to the steering angle, so that sharper bends require higher steering force. It is then also possible to achieve that the tilting speed back to the upright position is greater as the tilting from the upright position is greater.

It is preferable that in a tilted equilibrium position a small restoring force is continuously exerted, so that a torque or a force can be continuously exerted on the handlebar. When the steering wheel is released, the vehicle will automatically look for neutral driving straight ahead. Such a reset can be achieved, for example, by correct positioning of connecting members and excitation contacts and short-circuit contacts in connection with, for example, a twistable part, as will become clearer from the attached figure description.

The operation of the control system according to the invention can be speed-dependent, so that, for example, the operation is completely switched off during parking and unparking and / or other maneuvers at low speeds. In addition, a power steering system known per se can be included between the steering wheel and the directionally steerable wheel, which control is also speed-dependent, as is often customary.

In particular, for performing the tilting movement in which a vehicle part pivots relative to a positionally unchangeable vehicle part, it is preferable to use one or more sets of drive elements which assume an extreme position in the neutral (upright) position of the vehicle. The neutral position is easy to achieve in this way, and the drive elements do not require any special adjustment. Tilting from the neutral position can then be achieved by energizing either one or the other drive element. In that connection, for example, use can be made of a set of double-acting cylinder / piston assemblies as further described and shown in the figure description below.

Tilting can also be achieved by, for example, extending or shortening the wheel suspension as described, for example, in GB-A-2148217.

The invention finds application for both tricycles and multicycles. For a tricycle, think of two rear wheels arranged at a distance on either side of the center longitudinal axis, and a single front wheel arranged on the center longitudinal axis. For multi-wheelers, two front and two rear wheels are thought of with the same or almost the same track width, as with conventional passenger cars.

In connection with an advantageous operation of the system, even at low driving speeds, it is preferable to allow the bicycles arranged on or substantially on a common bend radius to differ in rotation speed. For the (rear) wheels centrally driven from a common drive motor, this can be achieved with a differential. For special circumstances such a differential action can be temporarily blocked, possibly gradually, for example depending on the driving speed or the size of the prevailing twisting between those bicycles.

The figure description relates to a non-limiting exemplary embodiment, which is currently considered to be the best embodiment of the invention, and reference is made to the accompanying drawings. Hereby shows:

Figure 1 schematically shows a perspective view of a three-wheeled vehicle according to the present invention;

Figures 2a to 2c in more detail the tilting mechanism as applied in the vehicle according to figure 1;

Figure 3a schematically shows a principle sketch of the hydraulic system which can be used in the tilting mechanism shown in figure 2;

Figure 3b shows a part of figure 3a in a following position;

Figure 3c shows a part of figure 3a, in a further position;

Figure 3d shows a detail of an embodiment variant of figure 3b; and

Figure 4 is a partial cross-sectional side view of a torque meter.

Figure 1 schematically shows a three-wheeled vehicle 1. It has two rear wheels 2 which are arranged coaxially at a distance on either side of the longitudinal axis of the vehicle 1. Furthermore, the one centrally disposed front wheel 3. The two rear wheels 2 are motor-driven. The drive unit 4, a conventional combustion engine, is arranged between the rear wheels 2, and its location is schematically shown in figure 2. As shown in figure 1, the front wheel 3 is rotatable via a front fork 5 about an axis located in the vertical plane 11 attached to part 9. The front fork 5 is oriented such that, viewed in the direction of travel, the axle 11 intersects in point 43 the ground which is located in front of the contact point 42 of the wheel 3 with the ground. A coupling is included between the handlebar 6 and the front fork 5. This coupling comprises a steering torque meter or steering force meter 7. The handlebar 6 can be directly coupled to the front fork 5, as for example with a conventional bicycle. Optionally, the coupling can be made via a transmission, for example steering rods, cables, etc. (not visible). The coupling can also be designed hydraulically, electrically, etc. The design of the meter 7 depends on the selected coupling. For example, said steering torque meter 7 is designed as shown in more detail in figure 3. The driver can sit behind the wheel 5 on a seat 8. Furthermore, the vehicle 1 shown in figure 1 is composed of two parts; a front part 9 and a rear part 10, which are designed to tilt about the longitudinal axis of the vehicle 1 relative to each other. At the front part 9 are the front wheel 3, the front fork 5, the handlebar 6, the steering torque meter 7 and the seat 8. At the rear part 10 are the two rear wheels 2 and the motor 4. The two rear wheels 2 are connected via a usually differential mutually coupled and 4 drives coupled to the motor. In another embodiment, the motor 4 can also be coupled in the tiltable part 9 of front wheel 3 to the further vehicle 1 in such a way that it is a so-called hub steering.

As shown in more detail in Figure 2, a tilt tube 21 runs at the bottom of the front part 9, which protrudes backwards from the front part 9. This tilt tube does not necessarily have to run horizontally. The center line of this tilting tube 21 defines the central longitudinal axis of the vehicle 1. This tilting tube 21 is rotatably inserted around its axis in a bearing bush (not shown) on the motor 4 of the rear part 10 of the vehicle 1. By means of this rotatable The bearing of the tilt tube 21 can tilt the front part 9 to the left and right around the center longitudinal axis of the vehicle 1, while the rear part 10 remains unchanged. During that tilting of the front part 9, the front wheel 3 will tilt in the same tilting sentence.

According to the invention, the steering deflection, or the steering force or the steering torque is measured in order to determine the degree of tilting, as more specifically explained in more detail with reference to Figure 3.

The tilting itself can be achieved with a tilting mechanism as shown in detail in figure 2. It shows two double-acting piston / cylinder combinations 22, 22 '. The free end of the piston rod 23 is pivotally connected to a mounting lip 24 on the motor 4. The free end of the piston rod 23 'is pivotally connected at a distance from the center line of the tilt tube 21 to a mounting lip 25 projecting from the tilt tube 21. on the opposite side, the piston / cylinder combinations 22, 22 'are hingedly connected to each other, and to a connecting rod 26 the other end of which is hingedly connected to a further mounting lip 27 on part 10 or part 9; here to the engine 4. In addition, 28, 28 'and 29, 29' respectively show the connection ports on the cylinders of the cylinder / piston combinations 22, 22 'for connection to the hydraulic circuit as, for example, more specifically described and shown in figure 3. Port 28 is directly coupled to port 29 '. The port 28 'is directly coupled to the port 29. As a result, no more than two lines run between the torque meter 7 and the cylinder / piston combination 22, 22'. However, ports 28, 28 ', 29, 29' need not be coupled as indicated, and more than two lines may be provided between torque meter 7 and cylinder / suction combinations 22, 22 '. If the pressure in port 28 is higher than that in port 29, vehicle 1 will tilt to the right. Tilting to the left occurs in the opposite situation. Figure 2 shows the position of the piston 30, 30 'in broken lines.

When driving straight ahead (Figure 2a), both piston rods 23, 23 'are in the maximum extended position and both pistons 30, 30' rest against respective stops (not shown) associated with the maximum end-of-stroke position. In that position, the front part 9 of the vehicle 1 is in neutral position, that is to say that it is erected vertically and the front wheel 3 is also erected vertically and is aligned in the straight-ahead position, i.e. parallel to the center longitudinal axis of the vehicle 1, and thus aligned parallel to the center line of the tilt tube 21. This position can be set reliably and efficiently because in that position both pistons 30, 30 'are in the extreme position. Figure 2b shows the right tilt situation in the drawing. Here, the piston 30 'of the cylinder / piston combination 22' is displaced, while the piston 30 preferably remains in place. The front wheel 3 is accordingly rotated to the right around the shaft 11. The front wheel 3 is also tilted to the right along with the part 9. Figure 2b shows the piston 30 'in the maximum retracted position. This corresponds to the maximum tilted position to the right. It will be clear that intermediate positions can also be taken up by the piston 30 ', with corresponding intermediate tilt positions.

Figure 2c shows the situation when the front part 9 is tilted to the other side, i.e. the left side in the drawing. The piston 30 is now displaced from the extreme position shown in Figure 2a, while the piston 30 'is preferably kept unchanged. Again, the front wheel 3 is turned accordingly, i.e. to the left.

The neutral position shown in Figure 2a is automatically reached from each inclined position if, for example, the maximum hydraulic pressure is active on either side of the pistons 30, 30 '. In such a case, the pistons 30, 30 'are automatically driven to the extreme position shown in Figure 2a because of the prevailing surface difference on either side of each piston due to the presence of the piston rod 23 and 23', respectively. By adjusting a pressure differential across the respective piston 30, 30 'through ports 28, 29 and 28', 29 ', a corresponding displacement of piston 30 and 30' can then be achieved depending on the direction and magnitude of the steering force or the steering torque and / or the steering angle, and / or the angular rotation of the front wheel 3 around the axle 11.

Obviously, other tilting mechanisms than those shown in figure 2 can also be used. For example, the cylinder / piston assemblies 22, 22 'can be replaced by one or more linear motors of a different type, such as, for example, electrically or magnetically driven. It is also possible, for example, to choose a rotating drive element, which can be integrated in, for example, the tilt tube 21. Instead of hydraulic operation, it is also possible to opt for pneumatic operation, for example. The set of cylinder / piston combinations 22, 22 'can also be replaced by a single cylinder / piston combination, the piston 28 of which, in the neutral, i.e. non-tilted, position of the front part 9 occupies a middle position between the two end-of-stroke positions. However, because of the precise and reliable adjustment of the neutral (straight-ahead position), the embodiment according to Figure 2 is preferred.

A hydraulic control, particularly advantageous in connection with the embodiment shown in Figure 2, is now discussed in more detail with reference to Figures 3 and 4. FIG. 4 shows the assembly of the steering torque meter 7 and the steering rod 31. The steering torque meter 7 comprises a substantially cylindrical housing 34 which is connected at one end in a rotatable manner to the steering rod 31. A steering slide 32 is inserted in that housing 34. This control slide 32 is rotatably connected to the control rod 31 at the free end of the housing 34, and surrounds the control rod 31 with play. On the outer circumference, the control slide is provided with a number of flattenings 35, 35 ', 36, 36', as is clearer from figure 3. If a torque is exerted on the handle bar 31, it will twist, so that the housing 34 relative to the control slide 32 will rotate. Figure 3 shows the steering torque meter 7 in cross section, incorporated in a schematically shown hydraulic system. On the cylindrical peripheral surface, the control slide 32 has two sets of diametrically opposed flanges, the flanges 35, 35 'of which are wider than the flanges 36, 36'. Eight ports 37 formed in the housing 34 open out to the housing inner wall and are spaced at equal angles over the circumference when viewed in cross section of the housing 34. As shown, the upper and lower ports 37 in the drawing are in fluid communication with a pressure pump 38 and a pressure accumulator 39. In the embodiment shown, the housing 34 and the control slide 32 are symmetrical in cross section. Optionally, an asymmetrical design is also possible, in which the accumulator is connected in only one place to the housing 34, and the ports 28, 29 'resp. 28 ', 29 are connected to the housing 34 via a common line.

The two ports 37 located in the horizontal horizontal plane in the drawing are both connected to a discharge pipe system 40, which optionally opens via the gear pump 41 into the pressure fluid collection vessel 42. In that pressure fluid collection vessel 42 there is a lower pressure compared to the pressure prevailing in the pressure accumulator 39. The optional gear pump 41 rotates at a speed proportional to the vehicle speed. The faster the gear pump 41 rotates, the less the gear pump 41 provides back pressure to the pressure fluid flowing out of the housing 34 and through the conduit 40. At low speeds of the gear pump 51, the pressure fluid will experience more nuisance, so that the operation of the tilting mechanism is hindered accordingly. This is advantageous, for example, in connection with parking and unparking, which conditions are associated with large steering deflections or steering moments / steering forces without tilting of the vehicle part 9 being desirable and even annoying. Instead of a gear pump 41, another element can be chosen for limiting the operation of the tilting mechanism at lower driving speeds. For example, a speed-controlled valve can be selected instead of the gear pump 41, which is closed further and further with decreasing speed.

The other nozzles 37 shown in the drawing are connected to the respective nozzles on the cylinder / piston combinations 22 and 22 ', respectively (see figure 2).

If a gear pump 41 is used, it is preferable to include a check valve 43 as shown to prevent pressure build-up and / or vacuum drawing in the pump and circuit due to the operation of the gear pump 41.

The operation of the pressure fluid system as shown in Figure 3 is as follows:

Figure 3a shows the neutral position of the control valve 32 inside the housing 34, which corresponds to the straight-ahead position of the vehicle 1. It can clearly be seen that the flattened parts 35 on the control valve 32 are large enough to accommodate the ports 28, 28 'and 29, 29' in fluid communication with the pressure accumulator 39. Thus the same pressure prevails on both sides of the pistons 30, 30 '(Figure 2), so that the pistons 30, 30' are in the extreme position shown in Figure 2 . The flattenings 36, 36 'are so small that in the neutral position of the control slide 32 they only communicate with the pressure fluid discharge line 40. The pressure fluid discharge line 40 is not in communication with the pressure accumulator 39 via the control torque meter 7.

With a slight rotation of the control slide 32 (for example to the right as shown in Figure 3b), the connection of the ports 28, 28 ', 29, 29' to the accumulator 39 is maintained. However, fluid can now also reach through the flattening 36, 36 ', in order to flow therewith in the line 40. The position of the control slide 32 relative to the housing 34 in this situation is shown in more detail in Figure 3d. Thus, in this position there is a "leakage" of fluid from the accumulator 39 to the conduit 40. Consequently, a pressure loss arises, the degree of which depends on the extent to which fluid can leak out. This enables reliable control of the tilting speed. When turning further to the right (Figure 3c), ports 28 and 29 'become disconnected from the pressure accumulator 39. They will then only be in communication with the line 40, and consequently there will be a loss of pressure in those lines, as a result of which the pistons will start to move. The vehicle 1 then tilts. As a result, the pressure difference over either the piston 30 or the piston 30 'will be sufficiently large for a displacement from the position shown in Figure 2a towards the position shown in Figures 2c and 2b, respectively. As the piston 30 or the piston 30 'moves, the control slide 32 will slowly rotate back to the position shown in Figure 3b, since the required steering force or torque or the required steering travel automatically decreases as the vehicle tilts. As soon as the equilibrium tilt position which corresponds to the prevailing conditions for following the bend is reached, the situation shown in figure 3b will prevail, whereby still a little steering force or steering angle must still be given by means of the handlebar 6. As soon as the handlebar 6 is turned back or released, the handle slide 32 will assume the position shown in figure 3a, or be further turned in the opposite direction, so that the pistons 30, 30 '(figure 2) are returned to the starting position as shown in figure 2a .

Naturally, further variants than those shown and described here also apply for the practice of the invention. For example, a conventional power steering mechanism may further be included between the handlebar 6 and the front wheel 3, in order to generate a portion of the steering force required for steering, particularly at low driving speeds. For example, it may be connected to the same pressure accumulator 39, pressure pump 38 and pressure fluid collection vessel 42 as shown in Figure 3a. Another embodiment of the steering torque meter, other than the embodiment shown in figure 3, can also be used. In addition, it is also possible, for example, to provide the vehicle with more than one direction-controllable wheel that moves with the tilting part of the vehicle. The steering torque meter 7 shown in figure 3 may also be suitable for electronic control.

For this purpose, the flattened parts 35, 35 'and 36, 36' can be designed as sl contact contacts and the positions of the mouths 37 determine the various electrical terminals with a power supply source, the earth and the terminals for one or more linear motors. Instead of measuring a torque, the meter 7 can also be designed for measuring a force. Then the prevailing normal force between the handlebars and the fork is applied. This is directly proportional to the steering torque applied. Within a housing provided with ports, a valve which can be slid in the longitudinal direction of the control rod can then be arranged, which controls the opening and closing of the ports depending on the developed control force. With, for example, resilient elements, the valve can be kept in the neutral position. Based on figure 3, the skilled person will be able to realize such an electronically controlled steering torque meter simply on the basis of his professional knowledge. However, preference is given to a hydraulic system, which provides greater reliability. Such reliability is particularly important for passenger vehicles.

Claims (13)

1. Self-balancing vehicle with at least three wheels resting on the ground, of which at least two are arranged on either side of the center of gravity relative to the longitudinal vehicle, and at least one of which is steerable, and at least part of the vehicle is tiltable around the vehicle longitudinal axle and with a steering means for controlling the at least one directionally steerable wheel a sensor is coupled to measure the size and / or direction of the load to cause and / or maintain a change of direction of the directionally steerable wheel while driving and / or the magnitude and / or direction of a change of direction of the directional wheel while driving, and an energized tilting element is provided for tilting said vehicle part around the vehicle longitudinal axis, which tilting element is coupled to the sensor to cause a tilting depending on the sensor's registration. Vehicle as claimed in claim 1, wherein the at least one directionally steerable wheel is tiltable with the tiltable vehicle part. Vehicle as claimed in claim 1 or 2, wherein the direction-controlled wheel has a trailing edge. Vehicle as claimed in any of the foregoing claims, wherein the steering member comprises a conventional steering wheel or steering box rotatable about a steering axle. Vehicle according to any one of the preceding claims, wherein the sensor comprises a twistable element which couples the control member and the directional control wheel, and the degree and direction of twisting is a measure of the size and direction of the load and / or the direction change of the direction steerable wheel. Vehicle as claimed in any of the foregoing claims, wherein the steering member can be brought out of its neutral position, which corresponds to driving the vehicle straight ahead, against the action of a restoring force generated by the energized tilting element. Vehicle as claimed in claim 5 or 6, wherein the circumferential twistable element is provided with circumferentially extending and spaced first and second connecting members, wherein the first connecting member extends a greater distance in the circumferential direction compared to the second connecting member. , and that first and second excitation contacts and a short-contact contact with mutually fixed position are arranged around the twistable element, which twistable element is rotatable relative to said contacts about its longitudinal axis, or vice versa, and wherein said contacts and said connecting members are arranged such that second connector is contactable with the shorting contact and either the first or second excitation contact, the first connector is contactable with both the first and second excitation contacts, and that when the first connector is in contact with both the e first if the second excitation contact, the second connector is only connected to the short-circuit contact (see fig. 3). Vehicle according to any of the preceding claims, wherein the operation of the sensor depends on the speed of the vehicle. Vehicle as claimed in any of the foregoing claims, wherein a further sensor for measuring the load for causing a change of direction of the direction-controlled wheel is included between the steering member and the direction-controlled wheel, which sensor is coupled to an energized drive element for reducing control load to be applied with the steering control, the operation of that second sensor possibly increasing with decreasing vehicle speed. Vehicle as claimed in any of the foregoing claims, wherein the vehicle part is tiltable around the longitudinal axis via two mutually coupled drive elements, which drive elements both assume an extreme position in the neutral position of the vehicle part, and optionally separately to the other respective extreme for respective tilting of the vehicle part in one direction or the other. Vehicle as claimed in claim 10, wherein two cylinder / piston assemblies with one end maintain a fixed mutual distance, while the other end of the respective cylinder / piston assembly is coupled at a distance from the tilting axis of the vehicle part to the tiltable vehicle part or the further vehicle part , and wherein the cylinder / piston assemblies are of the double-acting type. Vehicle according to any one of the preceding claims, wherein the driven bicycles are coupled on a common axis of revolution via a differential. Vehicle as claimed in any of the foregoing claims, wherein a position sensor is provided, which is included in a control circuit for determining the steering force exerted on the steering wheel depending on the steering angle and / or determining the tilting speed, respectively. the righting speed depending on the bend radius.