Articulated suspension for vehicles
Patent Information
- Application Number
- EP2024710205
- Authority / Receiving Office
- EP · EP
- Patent Type
- Applications
- Current Assignee / Owner
- Priority Date
- 2023-01-30
- Filing Date
- 2024-01-29
- Publication Date
- 2025-12-10
AI Technical Summary
Existing vehicle suspension systems, such as single-bar and parallelogram suspensions, suffer from coupling of various movements like heave and rolling, which induce yaw deviations and affect steering stability, leading to impaired riding comfort and increased load on the vehicle.
An articulated suspension design where horizontal bars are located on opposite sides of a vertical bar, allowing these bars to tilt independently, thus maintaining a constant distance between the supporting point and the frame, decoupling vertical movements from yaw orientation and surge translations.
This design effectively isolates the supporting point from frame movements, preventing yaw deviations and variable surge forces, enhancing steering stability and reducing loads on steering actuators, thereby improving riding comfort and accuracy.
Smart Images
Figure PT2024050002_08082024_PF_FP
Abstract
Description
[0001] DESCRIPTION
[0002] "ARTICULATED SUSPENSION FOR VEHICLES"
[0003] FIELD OF THE INVENTION
[0004] The present invention applies to suspensions, especially of vehicle axles, namely railway axles, with the aim of preventing the translational or rotational movements of the chassis from affecting steering.
[0005] In the context of vehicle suspensions, the words "chassis", "frame" and "sprung mass" are synonymous and will therefore be used interchangeably. When the device described in this patent application is applied to vehicle suspensions, the designations "horizontal" and "vertical", corresponding to the figures, generally coincide with the horizontal and vertical directions of the vehicle. However, this patent application covers applications where the suspension is used in another position, for example in positions where the vertical direction of the figures is inclined or horizontal.
[0006] PRIOR ART
[0007] Several patent applications (e.g. FR 2806693 Al) tried to avoid the coupling of the various degrees of freedom of suspensions, particularly of vehicles. In fact, the design of the vertical suspension, the lateral suspension and the rolling suspension of a wheeled vehicle is constrained by the coupling of these movements and their coupling with the wheels steering. In general, the movements of the chassis change the wheels' orientation by pulling or pushing one end of the axle in the forward direction. In turn, the orientation of the wheels and said displacement of the axle induce yaw movements or surge translations, which can reinforce the movements of the chassis and disturb the stability of the vehicle.
[0008] This general statement specifically applies to horizontal bar suspensions (e.g. US 8602428 B2) , or parallelogram suspensions (e.g. US 7114735 B2) , including articulations derived from the parallelogram (US 7222863 B2, US 20110221157 Al and CN 100482484 C) .
[0009] For instance, a suspension with a bar (1) linking a structure (2) to the supporting point (3) at the end of an axle or semi-axle, moves it horizontally when the frame is raised or lowered, in relation to the position in which the bar (1) is horizontal, as shown in Figs. 1-a) , 1-b) and 1-c) . Fig. 1-a) shows in the elevation the reference position, with bar (1) horizontal. Fig. 1-b) represents a position in which the frame (2) is raised in relation to the reference position, tilting bar (1) and causing therefore a horizontal displacement 63 of the supporting point (3) on frame (2) . Fig. 1-c) is a plan view illustrating the effect of having the structure (2) in its reference position (Fig. 1-a) on one side of the axis (4) and having it raised (Fig. 1-b) on the other side of that axis. On one side, the supporting point (3) at the end of the axis (4) is at the rated distance from the structure (2) (like in Fig. 1-a) and on the other side of the axle the supporting point (3) at the corresponding end of the axle (4) is at a smaller distance (like in Fig. 1-b) . It is therefore clear that uneven vertical movements of the frame, on one side and on the other, lead to yaw deviations in the steering of axle (4) relatively to frame (2) .
[0010] Due to the combination of the various movements, namely heave and rolling, it is possible for the frame (2) to rise on one side and drop on the other. The vertical translation ^2 of one side of the frame (2) induces a relative translation 63 of the supporting point (3) on that side. This point (3) can be one of the ends of a wheel axle (4) or a semi-axle. Let's look at two combinations of vertical displacements 62 and the corresponding horizontal displacements ^3.
[0011] If both ends of this rigid axle (4) are connected to the frame (2) by bars (1) aligned in the forward direction of the vehicle, an upward or downward movement 62 of the frame (2) , equal on both sides, tilts the two bars (1) equally and the orientation of the axle (4) does not change, because it retracts by the same distance 63 on both sides of the frame (2) . At most, if the wheels of the vehicle do not skid, this difference in speed between the frame (2) and the axle of the wheels temporarily increases the longitudinal force between the vehicle and the axle (4) .
[0012] If one side of the frame (2) remains level (Fig. 1- a) and the other side rises or falls (Fig. 1-b) , one of the bars (1) will remain horizontal while on the other side, where the structure undergoes a vertical translation 62, the corresponding supporting point (3) is subject to a relative retraction 63. If this supporting point (3) is the end of an axle (4) , as in Fig. 1-c) , the yaw orientation of the axle changes and the vehicle veers in the direction signalled by the dark arrows .
[0013] One can therefore understand that heave and rolling oscillations of the frame induce variable surge efforts and oscillations of the steering angle which, in turn, induce yaw and excite heave, sway and rolling movements of the frame. The coupling of these various movements means that steering defects impair the riding comfort and that the stability requirements and the freedom of movement of the various suspensions impact the steering stability.
[0014] Fig. 2 is analogous to Fig. 1, but instead of the supporting point (3) being connected to the frame (2) by a single bar (1) , there are two bars (6) and (7) connected to a vertical bar (8) which contains the supporting point (3) . The difference between the single-bar suspension of Fig. 1 and the parallelogram suspension of Fig. 2 is that, in the latter, the vertical bar (8) is forced to remain parallel to the frame (2) .
[0015] Parallelogram suspensions suffer from the same problem as single-bar suspensions. They keep bar (8) vertical, but the translations 62 of the frame (2) and the horizontal deviations of bars (6) and (7) (see Fig. 2) cause variations 63 of the distance between bar (8) and the frame (2) . This results in the same type of coupling of the single-bar suspension, in which the oscillations of frame (2) affect the wheel axle and the movements of the axle apply variable loads on frame (2) and reinforce its oscillations.
[0016] Variants of these configurations are very common on road vehicles and some rail vehicles. In certain road suspensions, the horizontal bars are aligned in a direction orthogonal to the vehicle's direction of travel. In this case, the movements 62 of the frame (2) produce displacements 63 which tend to cause the wheels to skid sideways and induce lateral loads on the vehicle.
[0017] HOW THIS INVENTION SOLVES THE AFOREMENTIONED TECHNICAL PROBLEMS
[0018] This patent application describes an articulation alternative to the parallelogram, in which the movements of the frame (2) do not impact the steering of the wheel axle and do not induce surge translations. Instead of the horizontal bars (9, 12 and 10, 13) being one over the other as in the parallelogram, they are located on opposite sides of the vertical bar (11, 14) and can have different lengths.
[0019] DESCRIPTION OF THE FIGURES
[0020] Figure 1. Schematic representation of a suspension according to the state of the art, which transmits forces from a support point (3) to a frame (2) by means of elastic and / or damping elements and a hinged bar (1) .
[0021] Fig. 1-a) is a schematic view in elevation, showing the suspension in its reference position, where the bar (1) is horizontal.
[0022] Fig. 1-b) is the same view in elevation, but with frame
[0023] (2) raised to a given height 62 in relation to the reference position, inducing a horizontal 63 displacement of the supporting point (3) relatively to the frame.
[0024] Fig. 1-c) shows, in plan view, the frame (2) connected by two suspensions of this type, where the supporting points
[0025] (3) are, each one, one end of an axle (4) , with wheels (5) . If the bar (1) of one of the suspensions is in the reference position (the upper bar of Fig. 1-c) corresponds to Fig. 1-a) ) , and the other bar (1) is inclined relatively to its reference position (like the lower bar in Fig. 1-c) , corresponding to Fig. 1-b) ) , the respective supporting points (3) have an offset 63 between them, which changes the orientation of the axle (4) in relation to the frame and causes the axle (4) to move with an yaw deviation (dark arrows) .
[0026] Figure 2. A similar scheme to that of Fig. 1, where instead of the supporting point (3) being connected to the frame (2) by a single bar (1) , there are two horizontal bars (6) and (7) connected to a vertical bar (8) containing the supporting point (3) . The difference between the singlebar suspension of Fig. 1 and the suspension of Fig. 2 is that, in the latter, the vertical bar (8) containing the supporting point (3) is forced to remain parallel to the frame ( 2 ) .
[0027] Fig. 2-a) is a view in elevation showing a suspension in the reference position, with the two bars (6) and (7) horizontal .
[0028] Fig. 2-b) is a view in elevation showing the suspension in a position where frame (2) is raised by a height 62 in relation to its reference position, inducing a displacement 63 of the supporting point (3) in relation to its reference position.
[0029] Fig. 2-c) shows in plan view the frame (2) connected by two suspensions of this type, at both ends (3) of an axle (4) , with wheels (5) . If one of the suspensions is in the reference position as in Fig. 2-a (plan view at the top of Fig. 2-c) and the other is inclined in relation to the reference position as in Fig. 2-b (plan view at the bottom of Fig. 2-c) , the respective supporting points (3) have a distance 63 between them in plan view, which changes the yaw orientation of the axle (4) in relation to that of frame (2) .
[0030] Figure 3. Schematic view in elevation of the suspension proposed in this patent application. The vertical bar (11) containing the supporting point (3) is connected to the frame (2) by two horizontal bars (9) and (10) located on opposite sides, where 69 is the horizontal projection of bar (9) . In addition to these bars, the suspension may include elastic and / or damping elements, as is usual. Figure 4. Scheme of the operating principle of the suspension of Fig. 3.
[0031] In the reference position, Fig. 4-a, the supporting point (3) is at a distance <523 from frame (2) .
[0032] Fig. 4-b illustrates the change in distances as a result of raising the frame (2) relatively to the supporting point (3) . The horizontal bars (9) and (10) tilt, so that the horizontal projection 5g of bar (9) decreases in relation to the reference situation, just as the horizontal projection <5io of bar (10) decreases in relation to its reference situation. As a result, the vertical bar (11) tilts in relation to its reference position, but the distance <523 between the supporting point (3) and the frame (2) does not change.
[0033] Accordingly, with this type of suspension distance <523 between the supporting point (3) and the frame (2) is independent of the relative movements of the supporting point (3) and frame (2) in the other directions. Thus, with the suspension of Fig. 4, there is no yaw deviation of the wheel axle (4) , like the one shown in Fig. 1-c) and Fig . 2-c) .
[0034] Figure 5. Fig. 5 is analogous to Fig. 4, showing the effect of lowering the frame (2) in relation to its reference position. As in Fig. 4-b, the horizontal projections 5g and <5io in Fig. 5-b change in relation to the reference position represented in Fig. 5-a, but the distance <523 remains the same.
[0035] Figure 6. This figure illustrates an asymmetrical configuration comparable to the symmetrical configuration of Fig. 3. The asymmetry consists of the horizontal bars
[0036] (12) and (13) having different lengths and the supporting point (3) being located asymmetrically on the vertical bar (14) . The rise 62 of the frame decreases the horizontal projections 612 and <513 of the horizontal bars (12) and (13) . As a result, the vertical bar (14) tilts (Fig. 6-b) . As the horizontal projections 612 and <513 are different, because the respective bars have different lengths, the centre of the vertical bar (14) moves horizontally in relation to the structure (2) , but the horizontal distance 623 between the support pointing (3) and the frame (2) experiences only a sub-millimetric variation, for typical dimensions of the suspension.
[0037] Figure 7. Fig. 7 almost reproduces Fig. 6, except that it exhibits a vertical drop 62 of frame (2) . The horizontal projections 612 and <513 are reduced, as in Fig. 6, and the vertical bar (14) tilts, as in Fig. 6. However, the variation in the horizontal distance 623 between the frame (2) and the supporting point (3) is sub-millimetric, because the supporting point is not vertically centered.
[0038] DETAILED DESCRIPTION OF THE INVENTION
[0039] Instead of the side bars (6) and (7) being one over the other, as in a parallelogram, the articulated suspension described in this patent application has the side bars (9) and (10) on opposite sides of the vertical bar (11) , as illustrated in Fig. 3. Figs. 4-a) and 5-a) illustrate the reference position. Fig. 4-b) shows that when the frame (2) rises 62, the side bars (9) and (10) tilt in opposite directions, causing the vertical bar (11) to rotate but preserving the horizontal distance <523 of its midpoint between the supporting point (3) and the frame (2) . Fig. 5-b) illustrates a similar situation, in which the frame (2) drops a distance 62. As can be seen in both figures, 4-b) and 5-b) , the horizontal projections 3g of the horizontal bar (9) and <5io of the horizontal bar (10) decrease equally, tilting the vertical bar (11) around its centre, the supporting point (3) . Thus, the supporting point (3) , being centred in the vertical bar (11) , maintains its horizontal distance <523 to the frame (2) . Therefore, if the ends of a rigid axle are connected to the frame (2) by suspensions of this type, the vertical movements of the frame (2) do not produce variable surge forces, nor do they change the steering angle of the axle.
[0040] Alternatively, the supporting point (3) could be not centred on the vertical bar (14) and the horizontal bars (12) and (13) could have different lengths. In this case, although geometric symmetry is lost, if the horizontal bars (12) and (13) have unequal lengths, in inverse proportion to the vertical offset of the supporting point (3) , the inclination of the bar (14) , due to the variation of the distances <512 and513, will only change sub-millimetrically the distance between the frame and the supporting point (3) on said bar. The distance <523 between the supporting point and the frame hardly changes, for suspensions of the usual size and for typical vehicle oscillations. The preferred ratio for the lengths of the bars (12) and (13) is the inverse of the ratio of the vertical offset of the supporting point (3) in the vertical bar .
[0041] The configuration herein proposed is directly applicable to active vehicle steering systems. In a single-bar suspension such as the one shown in Fig. 1, active steering is achieved by varying the length of the bars (1) on each side of the axle (4) , with the aforementioned drawback that the vertical movements of the frame (2) are coupled to the yaw movements of the axle. With the articulated suspension described in this patent application, active steering can be achieved with one or more linear actuators on just one of the horizontal bars, for example (10) or (13) , with the opposite horizontal bar, (9) or (12) respectively, being of constant length. By acting on only one of the horizontal bars, this arrangement increases the stroke of the linear actuator in relation to the stroke required to directly guide the supporting point (3) at one end of the shaft and decreases the load applied to this linear actuator. These two advantages are important because they increase the accuracy of the displacements of the supporting point (3) , the longitudinal rigidity of the steering and reduce the loads applied on the actuators .
[0042] PARTICULAR WAYS OF IMPLEMENTING THE INVENTION
[0043] The present patent application describes an articulated suspension for vehicles, that can provide an articulated connection between a frame (2) and a supporting point (3) linked to a vertical bar (11, 14) , orthogonal to the vehicle's forward direction.
[0044] In a preferred embodiment of the articulated suspension described in the present application, the vertical bar (11, 14) is connected to the frame (2) by means of two horizontal bars (9, 12 and 10, 13) , approximately parallel and non-collinear, connected to each end of the vertical bar (11, 14) on opposite sides of it, as in Figs. 3 and 6. When the vertical bar (11, 14) is in its reference position, the horizontal bars (9, 12 and 10, 13) , being orthogonal to the vertical bar (11, 14) , are also in their reference positions. In addition, the connections between the vertical bar (11, 14) and the horizontal bars (9, 12 and 10, 13) and between the horizontal bars (9, 12 and 10, 13) and the frame (2) are hinged connections, i.e. allowing relative angular rotation between the frame (2) and the horizontal bars (9, 12 and 10, 13) and between them and the vertical bar (11, 14) . In this way, the distance <523 between the supporting point (3) and the frame (2) becomes independent of the relative movements between the supporting point (3) and the frame (2) , which means that the movements of frame (2) do not affect the yaw orientation of the vehicle's wheels' axle (deviation of the axle's yaw angle) , nor do they induce surge translations.
[0045] In an alternative design of the articulated suspension described in this application, the supporting point (3) is centred on the vertical bar (11) and the two horizontal bars (9, 10) are of equal length. The supporting point (3) centred on the vertical bar (11) is equidistant from both ends of bar (11) . Alternatively, the supporting point (3) is not centred on the vertical bar (14) and the two horizontal bars (12, 13) have different lengths. More specifically, the length of each horizontal bar (12, 13) is inversely proportional to the vertical offset of the supporting point (3) in relation to the vertical bar (14) , to which the horizontal bars (12 and 13) are connected.
[0046] In an alternative embodiment of the articulated suspension described in this application, the length of one horizontal bar is variable and the length of the other horizontal bar is constant. In particular, the length of the variable-length horizontal bar can be controlled by at least one linear actuator. This makes it possible to apply the articulated suspension to active vehicle steering systems.
[0047] In an alternative design of the articulated suspension described in this application, the supporting point (3) is not collinear with the ends of the vertical bar (11, 14) . In an alternative design of the articulated suspension described in this application, the suspension also includes elastic and / or damping elements, in particular at the connection between the frame (2) and the connecting point of the vertical bar (11, 14) and the horizontal bar (10, 13) .
[0048] In an alternative embodiment of the articulated suspension described in this application, the supporting point (3) connects the end of an axle of the vehicle to the vertical bar (11, 14) ; or the supporting point (3) connects the end of a half-axle of the vehicle to the vertical bar (11, 14) .
[0049] Also within the scope of this patent application is an articulated suspension system for a vehicle, comprising at least two articulated suspensions as described here. Each articulated suspension would be connected to the frame (2) of the vehicle via horizontal bars (9, 12 and 10, 13) and to the end of an axle or semi-axle of the vehicle via the supporting point ( 3 ) .
Claims
CLAIMS1. Articulated suspension for vehicles, apt to establish an articulated connection between a frame (2) and a supporting point (3) connected to an approximately vertical bar (11, 14) characterized in that the vertical bar (11, 14) is connected to the frame (2) by two approximately horizontal bars (9, 12 and 10, 13) , approximately parallel and non-collinear, connected to each end of the vertical bar (11, 14) on opposite sides of the bar (11, 14) , and approximately orthogonal to it; and that the connections between the vertical bar (11, 14) and the horizontal bars (9, 12 and 10, 13) and the connections between the horizontal bars (9, 12 and 10, 13) and the frame (2) are hinged connections.
2. Articulated suspension according to claim 1, wherein the supporting point (3) is centred on the vertical bar (11) ; and the two horizontal bars (9, 10) are of equal length.
3. Articulated suspension according to claim 1, wherein the supporting point (3) is not centred on the vertical bar ( 14 ) ; and the two horizontal bars (12, 13) have different lengths.
4. Articulated suspension according to claim 3, wherein the length of each horizontal bar (12, 13) is inversely proportional to the vertical offset of the supporting point (3) on the vertical bar (14) to which the horizontal bar (12, 13) is attached.
5. Articulated suspension according to any of the preceding claims in which the length of one horizontal bar is variable and the length of the other horizontal bar is constant .
6. Articulated suspension according to claim 5, wherein the length of the variable-length horizontal bar is controlled via at least one linear actuator.
7. Articulated suspension according to any of the preceding claims, wherein the supporting point (3) is noncollinear with the ends of the vertical bar (11, 14) .
8. Articulated suspension according to any of the preceding claims, additionally comprising elastic and / or damping elements; said elements making the connection between the frame (2) and the connection point of the vertical bar (11, 14) with a horizontal bar (10, 13) .
9. Articulated suspension according to any of the preceding claims, wherein the supporting point (3) connects the end of an axle of the vehicle to the vertical bar (11, 14) .
10. Articulated suspension according to any one of claims 1 to 8, wherein the supporting point (3) connects the end of a vehicle half-axle to the vertical bar (11, 14) .
11. Articulated suspension system for vehicles comprising at least two articulated suspensions as described in claims 1 to 10; wherein each articulated suspension is connected to the frame (2) via horizontal bars (9, 12 and 10, 13) and to the end of an axle or a semi-axle of the vehicle via the supporting point (3) .