VEHICLE GAS SPRING, ANTI-ROLL DEVICE AND METHOD USING SUCH GAS SPRINGS
The invention relates to a vehicle provided with at least one spring bellows filled with a gas, the spring bellows being placed between a first and a second vehicle part to spring the second vehicle part relative to the first vehicle part, the vehicle being provided with an anti- heeling device arranged to inhibit heeling of the vehicle.
Such a device is known from U.S. Patent 3,572,747. The known vehicle is provided with a pneumatic spring system with bellows supporting the vehicle on each vehicle side. The vehicle is further provided with means for regulating the gas pressure in the bellows for the purpose of changing the height of each bellows. The anti- heeling device of the known vehicle is connected to these means, such that the anti-heeling device can inhibit heeling of the vehicle by changing the gas pressure in the bellows and, therefore, the size of the bellows. The heeling may be the result, for instance, of the compression of one or more spring bellows located on one side of the vehicle when the vehicle takes a bend, which heeling can be inhibited by the anti-heeling device by increasing the gas pressure in these gas bellows. In such a vehicle, the second vehicle part may comprise, for instance, a vehicle chassis part to be sprung, while the first vehicle part is provided with one or more wheel axles with at least one vehicle wheel. By using a pneumatic spring system, at least a spring system provided with at least one spring bellows, a very comfortable and stable springing of at least the second vehicle part relative to the first vehicle part can be effected. A drawback of the known vehicle is that the anti-heeling device thereof is often not capable of sufficiently inhibiting a relatively great heeling of the vehicle, since the bellows can undergo only a limited
expansion or reduction. Such a great heeling may occur particularly in relatively high vehicles, such as double-deckers or trailer trucks provided with high loading spaces. Such a heeling is uncomfortable for passengers of the vehicle and can lead to the tilting of the vehicle. Moreover, it turns out that an anti-heeling device system based on variation of gas pressure cannot react rapidly enough to a sudden heeling of the vehicle, for instance in case of a sudden change of a driving direction of the vehicle. Another drawback is that, at least in a relatively slack adjustment of the pneumatic springing, the second vehicle part to be sprung will usually wobble a little during the drive. This wobbling may be increased as a result of the delayed action of the anti-heeling device, which can lead to uncontrollable ness and/or tilting of the vehicle.
The present invention has for its object to remove the drawbacks of the known vehicle. In particular, the invention has for its object to provide a vehicle with at least one spring bellows filled with a gas, by which a heeling of the vehicle can be inhibited relatively well.
To this end, the vehicle according to the present invention is characterized in that the anti-heeling device is provided with lifting means operable by a control, which means are arranged to change, during operation, a distance between the spring bellows and one of the two above vehicle parts.
The lifting means can effect the distance between the at least one spring bellows and the above vehicle part in a simple and relatively rapid manner, so that a sudden heeling of the vehicle can be rapidly inhibited. Moreover, the lifting means can inhibit a relatively great heeling in a simple manner through a relatively great change of that distance. The lifting means may comprise, for instance, a hydraulically drivable piston/cylinder assembly. Such a hydraulic mechanism can provide a substantially time-invariant operation of the lifting means. Moreover, a hydraulic piston/cylinder assembly may be of relatively robust design.
According to an advantageous elaboration of the invention, the one vehicle part located at the above distance from the spring bellows, to be changed by the lifting means, is provided with a spring bellows chamber, which chamber is placed between that vehicle part and the spring bellows, the spring bellows being arranged to enclose at least a part of an outer side of the above spring bellows chamber.
Such a spring bellows chamber may be formed, for instance, such that the chamber can influence the spring behavior of the spring bellows in a desired manner, so that a specific desired springing of the second vehicle part is obtained. Furthermore, this chamber may, for instance, support the respective spring bellows. The spring bellows may be coupled to the spring bellows chamber in different manners, for instance fixedly or detachably. Each spring bellows chamber may, for instance, further be connected to the vehicle part in different manners. According to a preferred embodiment of the invention, the spring bellows chamber is movable in a substantially vertical direction, the lifting means being arranged to change a distance between that vehicle part and the chamber.
In this manner, the spring bellows can be located, for instance, in a fixed position on or below the spring bellows chamber, the spring bellows and the bellows chamber being jointly movable by the lifting means relative to the above one vehicle part in the substantially vertical direction. In this case, the spring bellows may, for instance, be fixedly connected to the spring bellows chamber, so that shifting of the bellows relative to the chamber is prevented.
According to a further elaboration of the invention, the lifting means are placed at least partly within the spring bellows chamber.
In this manner, the inner space of the spring bellows chamber is usefully used by the lifting means, so that vehicle space can be saved in a simple manner. For the purpose of changing the above distance, the lifting
means may, for instance, be simply coupled to the spring bellows chamber and/or the above one vehicle part provided with that chamber.
The invention further provides an anti-heeling device which is characterized by the measures of claim 13. Such an anti-heeling device can be mounted in a vehicle in a relatively simple manner and can protect the vehicle from heeling relatively well.
The invention also relates to a method of providing a vehicle with an anti- heeling device, the vehicle being provided with at least one spring bellows placed between a first and a second vehicle part to spring the second vehicle part relative to the first vehicle part.
Such a method is known from the above U.S. Patent 3,572,747. In this method, the vehicle is provided with an anti-heeling device which is arranged to inhibit heeling of the vehicle by changing the gas pressure in the bellows. A drawback of the known method is that the resulting anti- heeling device is based on a pneumatic regulation of the height of the air bellows, which leads to a relatively poor protection of the vehicle from tilting.
The present invention has for its object to remove this drawback and therefore provides a method which is characterized in that the vehicle is provided with lifting means operable by a control, which are arranged to change, during operation, a distance between the spring bellows and one of the two above vehicle parts.
In this manner, the vehicle can be provided with an anti-heeling device which can inhibit a relatively great heeling of the vehicle in a relatively rapid manner.
When the one vehicle part located at the above distance from the spring bellows, to be changed by the lifting means, is provided with a spring bellows chamber, which chamber is placed between that vehicle part and the spring bellows, the spring bellows being arranged to enclose at least a part of an outer side of the above spring bellows chamber, it is very
advantageous if the lifting means are placed at least partly within the spring bellows chamber.
A vehicle which is already provided with at least one spring bellows and a respective spring bellows chamber may thus be provided with the lifting means of the anti-heeling device in a very simple, rapid and inexpensive manner. An extensive adaptation of the vehicle to provide the vehicle with the anti-heeling device can therefore be avoided. Moreover, the lifting means thus need to fill relatively little or no other separate space of the vehicle than the inner space of the bellows chamber, so that the other space available in the vehicle can be used optimally, for instance as loading space.
Further elaborations of the invention are described in the subclaims. The invention will now be described on the basis of an exemplary embodiment and the drawing. In this drawing: Fig. 1 is a side view of an exemplary embodiment of the invention;
Fig. 2 is a cross-section on the line II-II of the exemplary embodiment shown in Fig. 1;
Fig. 3 shows detail Q of the cross-section shown in Fig. 2; and Fig. 4 shows detail R of the cross-section shown in Fig. 2. Fig. 1 is a diagrammatic side view of a vehicle 1, of which a sprung second vehicle part comprises a chassis plate 3, which is provided with a cabin 6 and a loading space 2. The vehicle is further provided with wheels 5, which are coupled to wheel axles 4 in a manner known to those skilled in the art. The vehicle is provided with a pneumatic spring system 7, which provides springing of the chassis plate 3 relative to the wheel axles 4. The spring system 7 is provided with spring bellows 8 filled with a gas, which each extend over an upper wall 9a and a part of a side wall 9b of a bellows chamber 9, the side wall extending from the upper wall 9a in a downward direction. Each spring bellows 8 and respective bellows chamber 9 are rotation symmetric about an axis of rotation 13 shown in Figs. 3 and 4. The
spring bellows 8 and respective bellows chambers 9 are arranged between the chassis plate 3 to be sprung of the vehicle, on the one hand, and the wheel axles 4 of the vehicle, on the other hand. The bellows chambers 9 may give the spring bellows 8, for instance, a specific, desired support. By using the spring bellows 9, a very good, comfortable springing of the vehicle can be obtained, i.e. relative to, for instance, a spring system provided with wire-shaped metal springs. Moreover, the spring bellows 9 can bear relatively high loads and are therefore very suitable for use in trucks, autobuses, trains and the like. As Fig. 2 further shows, the wheel 5 located on one side of the vehicle is, moreover, coupled by the respective wheel axle 4 to the wheel 5 located on the other vehicle side. This construction, in which the wheels 5 are sprung depending on each other, also gives the vehicle a relatively great stability, while through this construction the vehicle can bear a relatively great load. Figs. 1-4 further show that the vehicle 1 is provided with an anti- heeling device which comprises lifting means 10, 11 operable by a control. This control is not shown in the drawing and may comprise, for instance, a microprocessor, computer and/or such control means known from practice. Furthermore, this control is provided with sensor means not shown, which are arranged to detect a heeling of the vehicle 1 relative to a longitudinal axis of the vehicle. Such sensor means may comprise, for instance, electronic means, a pendulum, leveling means, a mercury switch or a combination of these or other sensor means.
The lifting means 10, 11 are designed as a hydraulically drivable piston/cylinder assembly 10, 11 placed below each spring bellows 8 and substantially within the respective bellows chamber 9. Center lines of the piston/cylinder assemblies 10, 11 coincide with the axes of symmetry 13 of the bellows 8 and the bellows chambers 9. The piston 11 of each assembly 10, 11 extends from the cylinder 10 to an upper wall 9a of the respective chamber 9. The vehicle 1 is provided with fluid supply and regulating
means not shown, to regulate fluid supply to each piston/cylinder assembly 10, 11 for the purpose of operating the piston 11. Each piston 11 can, during operation, change a distance between the bellows 8 and the respective chamber 9, on the one hand, and the respective wheel axle 4, on the other hand, which distance is indicated in Figs. 3 and 4 by the arrows L and L', respectively. The above control is arranged to change the distance L, L' from the spring bellows 8 relative to the wheel axles 4 such that a heeling detected by the above sensor means is thereby inhibited. The control may be arranged, for instance, to inhibit heeling of the vehicle fully automatically through regulation of the anti-heeling device.
During use, the vehicle 1 may move, for instance, over a substantially horizontal flat bottom, each spring bellows 8 being in the position shown in Fig. 3. The chassis plate 3 is then located at a specific height H relative to the wheel axle 4. As shown in Fig. 3, the piston 11 is, in that case, located substantially completely within the cylinder 10 in the spring bellows chamber 9. When the above sensor means detect a heeling of the vehicle, for instance a heeling as a result of a bend taken by the vehicle 1, the above control can inhibit this heeling through operation of the piston 11, such that the piston 11 is pressed out of the cylinder 10 over a distance L. The position of the piston 11 pressed out of the cylinder 10 is shown in Fig. 4. By displacing the piston 11, the spring bellows 8 and the respective spring bellows chamber 9 are pressed up, so that the chassis plate 3 removes from the wheel axle 4 to a height H' relative to the wheel axle 4. As shown in Fig. 2, the control can inhibit a heeling of the vehicle on a vehicle side, which side is shown in the figure with reference numeral Z, for instance by causing the spring bellows 8 located on that side Z to move up through operation of the respective piston/cylinder assemblies 10, 11. It should be noted that the described heeling on the vehicle side Z can be effected partly or completely by the spring bellows 8 located on that vehicle side Z being slightly compressed relative to bellows 8 located on the opposite vehicle side
Y. Such a volume change of one spring bellows 8 relative to the others is not shown in the figures.
It is self-explanatory that the invention is not limited to the described exemplary embodiment. Various modifications are possible within the scope of the invention as phrased in the following claims.
Thus, the lifting means may be, for instance, of hydraulic and/or mechanical design. As regards lifting means of hydraulic design, these may be provided with, for instance, a separate fluid source and/or connected to a standard vehicle fluid circuit, such as a brake fluid system. Furthermore, each bellows chamber 9 may be of different design, for instance cylindrical, conical, truncated, spherical or a combination of these or other shapes. Upper walls 9a and side walls 9b of each chamber 9 may extend in different directions, for instance along straight, angular and/or curved surfaces. Furthermore, the first and/or second vehicle part may be provided with a bellows chamber. Each bellows chamber 9 may further be coupled to a first or second vehicle part in different manners, for instance through fastening means, such as nut/bolt assemblies, fastening plates, welded joints or the like.
Besides, the control may be arranged in different manners. The control may be arranged, for instance, to operate the lifting means 10, 11, depending on a driving speed of the vehicle. Thus, for instance, the control may be switched on automatically when the driving speed of the vehicle exceeds a specific threshold value.
Furthermore, the control may be provided with driver operating means arranged near a driver seat in the vehicle 1, for instance in a cabin 6 of the vehicle 1. The driver operating means may then be arranged to manually regulate a position of the lifting means of the anti-heeling device, so that one or a few spring bellows are kept at a desired distance from at least one of the two vehicle parts 3, 4, so that the vehicle parts 3, 4 are located at a desired distance relative to each other. The driver operating
means may comprise, for instance, a switch, push button or the like, which can be brought, for instance, into different operating conditions. Furthermore, the driver operating means may be intended, for instance, for switching on or off the anti-heeling device, so that the vehicle is or is not protected by the anti-heeling device from undesirable heeling.
Furthermore, the one vehicle part located at the above distance from the spring bellows, changeable by the lifting means, may be the first vehicle part or the second vehicle part. Moreover, the vehicle may be provided with different lifting means which are arranged to change mutual distances between a spring bellows, on the one hand, and each of the two vehicle parts, on the other hand.
Besides, different gases or gas mixtures, for instance nitrogen, air or the like, may be used to fill the spring bellows 8.
Furthermore, the spring bellows chamber 9 may be provided, for instance, with at least one opening 12, the lifting means 11, 12 being arranged to engage the spring bellows 8 from the spring bellows chamber 9 via the opening 12, for the purpose of changing the distance between the upper and the lower vehicle part 3, 4. Thus, the lifting means can simply reach the spring bellows from the bellows chamber, for instance to move the bellows in a direction away from the spring bellows chamber and/or towards the spring bellows chamber, depending on the distance between the chamber and the spring bellows and a degree of heeling of the vehicle. The opening may be made, for instance, by separating a wall part of the bellows chamber, extending below or above the bellows, from another part of the bellows chamber wall, for instance by sawing, cutting or the like. The lifting means may then be easily coupled to the separated bellows wall part, such that the lifting means can move that wall part out of and into the opening, so that the bellows with that wall part is moved in a direction from the spring bellows chamber away and towards the spring bellows chamber, respectively.