Tilting saddle motor vehicle with a four-bar linkage with reduced roll

Abstract

A tilting motor vehicle comprising a pair of steered front wheels (17A, 17B) linked to the frame (3) of the motor vehicle (1) by a roll four-bar linkage (21). The roll four-bar linkage comprises an upper crosspiece (23) and a lower crosspiece (25) linked to each other by uprights (27A, 27B) forming a four-bar linkage. One of the two crosspieces is made up of a front half-crosspiece and a rear half-crosspiece, both hinged to the two uprights. The other half-crosspiece comprises two half-crosspieces, only one of which is hinged at its ends to the two uprights, while the other half-crosspiece is shorter and it is not hinged to the uprights.

Description

Technical Field

[0001] This invention relates to the field of so-called tilting or swaying motor vehicles, i.e., motor vehicles configured to tilt about a central plane extending longitudinally along the vehicle. The embodiments disclosed herein relate to saddle-type vehicles having three or more wheels, particularly two steering front wheels and at least one rear drive wheel. Background Technology

[0002] In the realm of motor vehicles, an increasing number of vehicles combine the ease of handling of two-wheeled saddle-riding vehicles (such as motorcycles and motorized bicycles) with the stability of four-wheeled vehicles. These vehicles include three-wheeled motor vehicles with two front steering wheels and one rear drive wheel, as well as four-wheeled motor vehicles commonly referred to as QUADs.

[0003] More specifically, the aforementioned three-wheeled motor vehicle is equipped with two front steering wheels configured so that the rider controls the steering of the vehicle via handlebars, and these wheels are tilted, i.e., they tilt or can yaw laterally with tilting motion. Tilting motion is a pivoting motion about an axis that is substantially oriented in the direction of travel. Furthermore, the three-wheeled vehicle includes a rear drive wheel that is driven into the engine and designed to supply drive torque and thus allow traction, while a pair of front wheels are designed to provide directional control of the vehicle.

[0004] In addition to steering movement, the paired front wheels are also configured for roll movement, and they are connected to the vehicle's frame via a shock absorber suspension that allows the spring suspension to move. Because of the use of two pairs of front wheels, the roll vehicle ensures greater stability compared to a motor vehicle with only two wheels, through the double support of the front wheels on the ground (similar to the double support provided by a car).

[0005] The front wheels are interconnected by kinematic mechanisms that ensure the wheels roll and steer substantially synchronously, for example by inserting one or two four-bar linkages that link the front wheels to the front wheel carrier frame. These four-bar linkages will also be referred to below as "roll four-bar linkages". Furthermore, the motor vehicles considered in this paper often feature two independent damping suspensions, one for each front drive wheel. Each suspension includes an elastic element (spring) and a viscous element (shock absorber).

[0006] The four-bar linkage that links the front steering wheels to the frame must have high mechanical strength to withstand the dynamic loads it experiences. Therefore, the roll four-bar linkage must be appropriately sized, and it is a bulky and heavy component of the vehicle, which negatively and significantly impacts the vehicle's cost and ease of handling.

[0007] It would be advantageous to provide a saddle-riding tilting motor vehicle equipped with a tilting four-bar linkage, which completely or partially overcomes the disadvantages of the prior art. In particular, it would be advantageous to provide a vehicle with a tilting four-bar linkage that is lighter and easier to handle, more cost-effective, yet possesses sufficient mechanical strength. Summary of the Invention

[0008] Essentially, this document discloses a tilting motor vehicle comprising a pair of front steering wheels connected to the frame of the motor vehicle via a tilt four-bar linkage. The tilt four-bar linkage includes an upper crossbar and a lower crossbar, which are linked to each other via posts forming rocker arms of the four-bar linkage. One of the two crossbars, preferably the lower crossbar, consists of a front half-crossbar and a rear half-crossbar, both of which are hinged to two posts. The other half-crossbar, preferably the lower half-crossbar, comprises two half-crossbars, of which only one (preferably the front half-crossbar) (at its end) is hinged to the two posts, while the other half-crossbar (preferably the lower half-crossbar) is shorter and is not hinged to any post.

[0009] In particular, a tilting or lateral saddle-mounted motor vehicle is provided, comprising a tilting four-bar linkage having an upper crossbar hinged at its midpoint to a central element of a frame; wherein the upper crossbar comprises a front half-crossbar disposed in front of the central element of the frame and a rear half-crossbar disposed behind the central element of the frame. The front and rear half-crossbars form a single rigid body through which the central element of the frame extends. The tilting four-bar linkage also includes a lower crossbar hinged at its midpoint to the central element of the frame; wherein the lower crossbar comprises a front half-crossbar disposed in front of the central element of the frame and a rear half-crossbar disposed behind the central element of the frame. The front and rear half-crossbars form a single rigid body through which the central element of the frame extends. The tilting four-bar linkage also includes a left column hinged to the left end of the upper crossbar and the left end of the lower crossbar. The left steering wheel is linked to the left column for rotation about the left steering axis. Additionally, the roll four-bar linkage includes a right column hinged to the right ends of the upper and lower crossbars. The right steering wheel is linked to the right column for rotation about the right steering axis.

[0010] Characteristically, in order to reduce the weight and cost of the roll four-bar linkage while maintaining appropriate rigidity and increasing the ease of handling of the vehicle, in the embodiments described herein, for one of the two crossbars (upper crossbar and lower crossbar, respectively), the length of one of the front and rear half-crossbars is greater than the length of the other half-crossbar. The longer half-crossbar is directly hinged to the left and right pillars via corresponding left and right hinges, while the shorter half-crossbar is not directly hinged to the left and right pillars.

[0011] Conversely, the front and rear halves of the other horizontal bar in the upper and lower horizontal bars are directly hinged to the left column via the left hinge, and directly hinged to the right column via the right hinge.

[0012] Essentially, one of the two crossbars consists of a half-crossbar, which contributes to the rigidity of the crossbar but is not hinged to the column of the four-bar linkage. In this way, while maintaining the appropriate mechanical strength and rigidity of the system formed by the four-bar linkage, its weight and cost are reduced compared to a four-bar linkage with two crossbars (each crossbar consists of a front half-crossbar and a rear half-crossbar, both of which are hinged to the column by corresponding hinges).

[0013] Preferably, for reasons explained below, the shorter half-bar belongs to the upper bar, and more preferably to the lower half-bar.

[0014] Unless otherwise indicated, in this specification and the appended claims, the terms "above," "below," "front," "rear," "right," "left," "upper," "lower," "forward," and "rear" refer to the position of the corresponding component or part when the motor vehicle is in a straight, non-steering, and non-tilting position. The terms "forward" and "rear" refer to the direction of travel of the motor vehicle.

[0015] The "right" and "left" indicators refer to the rider of a vehicle in the correct riding position, sitting on the saddle of the vehicle facing forward relative to the normal direction of travel of the vehicle. Attached Figure Description

[0016] The invention will become clearer from the description and accompanying drawings, which illustrate embodiments provided by way of non-limiting examples of the invention. More specifically, in the drawings:

[0017] Figure 1 It is an axonometric view of a motor vehicle, with some parts removed;

[0018] Figure 2 This is a front view of the front steering wheel, suspension, and roll bar four-bar linkage.

[0019] Figure 3 It is an axonometric view of the tilting four-bar linkage on the rider side; and

[0020] Figure 4 It is based on Figure 2 The second cross section of the vertical midline plane of the upper crossbar of the steering tube and the tilt four-bar linkage in plane IV-IV. Detailed Implementation

[0021] Figure 1An axonometric view of a motor vehicle 1 according to one embodiment is shown. Figure 1 In other diagrams, arrow U indicates the upward direction, arrow D indicates the downward direction, and arrows L and R indicate the left and right directions, respectively. Finally, F and B indicate the forward (driving) direction and the backward direction, respectively.

[0022] The motor vehicle 1 includes a frame 3, with rear drive wheels 5 connected to the frame 3. The drive wheels are connected to an engine (not shown). The saddle of the motor vehicle 1 is schematically shown at point 9. Figure 1 In this designation, the body panels, engine and related drive components of the motor vehicle, as well as any other components that are not useful for the understanding of the invention, are omitted.

[0023] In other embodiments not shown, the motor vehicle 1 may include two rear drive wheels instead of a single drive wheel.

[0024] At the front, the motor vehicle 1 includes a front wheel frame 11, which includes a handlebar, a pair of steering front wheels, and a mechanism for connecting the steering front wheels and their suspension to the frame 3 so as to allow the motor vehicle to perform a tilting motion, i.e., a pivoting movement about a horizontal axis parallel to the direction of travel and located on the ground, i.e. on the surface on which the motor vehicle is placed.

[0025] More specifically, the front wheel carrier 11 includes a steering column 13 to which the handlebars, schematically shown in dashed lines at 15, are linked. The steering column 13 is rotatably received in a steering tube 14, which is integrally connected to the frame 3 or a portion thereof. Using the steering column 13, the rider transmits steering motion to the two front steering wheels, and more precisely, the left front steering wheel 17A and the right front steering wheel 17B. The steering motion is transmitted to the front steering wheels 17A and 17B via a steering lever 16.

[0026] Shock absorbers, typically comprising elastic and viscous components, are associated with each front steering wheel 17A, 17B. More precisely, the left shock absorber associated with the left front steering wheel 17A is indicated by 19A, and the right shock absorber associated with the right front steering wheel 17B is indicated by 19B.

[0027] The front steering wheels 17A and 17B and their associated shock absorbers 19A and 19B are connected to the frame 3 to allow the front steering wheels 17A and 17B to rotatably move (steer) about their respective steering axes, wherein the steering axis for the left front steering wheel 17A is indicated by Xa, and the steering axis for the right front steering wheel 17B is indicated by Xb. Furthermore, the linkage mechanism from the front steering wheels 17A and 17B to the frame 3 is configured to allow the vehicle 1 to perform lateral movement, i.e., for example, when the vehicle is driving around a curve, for example, around a support surface passing through the vehicle (in... Figure 2The horizontal axis (indicated by S) is deflected. Lateral roll is caused by... Figure 2 The double arrow R in the diagram is shown schematically.

[0028] To allow these movements, the front guide wheel frame 11 of the motor vehicle 1 includes a tilt four-bar linkage 21, which forms a mechanical linkage component between the front steering wheels 17A, 17B and the frame 3.

[0029] The tilting four-bar linkage 21 (hereinafter referred to as the four-bar linkage 21) includes an upper crossbar 23 and a lower crossbar 25 linked to the frame 3 as described herein. The four-bar linkage 21 also includes a left column 27A and a right column 27B, which form rocker arms of the four-bar linkage 21 and are hinged to the upper crossbar 23 and the lower crossbar 25 as described herein. In the illustrated embodiment, the left front steering wheel 17A and the left shock absorber 19A are linked to the four-bar linkage 21 via a left arm 20A rotatably housed in the left column 27A for rotation about the left steering axis Xa. Similarly, the right front steering wheel 17B and the right shock absorber 19B are linked to the four-bar linkage 21 via a right arm 20B rotatably housed in the right column 27B for rotation about the right steering axis Xb.

[0030] The upper crossbar 23 is hinged to the central element 3C of the frame 3 at the midpoint of its longitudinal extension (see...). Figure 4 For example, elements hinged to or integrally connected to the steering tube 14. The intermediate hinge point of the upper crossbar 23 is marked 29. Essentially, hinge point 29 defines a central hinge axis 29A about which the upper crossbar 23 rotates relative to the frame 3. The central hinge axis 29A lies in the vertical center plane of the vehicle, and its line intersects with... Figure 2 The axis AA coincides. The hinge axis 29A extends in the direction of the central plane and is deflected from top to bottom in the direction of arrow B, which is opposite to the direction of travel (arrow F).

[0031] In a specific embodiment, the hinge between the central element 3C and the upper crossbar 23 is defined by two bearings 31 and 32, which are respectively arranged in front of and behind the central element 32C of the frame 3 relative to the vehicle travel direction defined by arrow F.

[0032] The upper crossbar 23 includes a front half crossbar 231 arranged in front of the central element 3C relative to the vehicle's direction of travel (arrow F) and a rear half crossbar 233 arranged behind the central element 3C of the frame 3. (See also...) Figure 3 As can be seen, the front half of the crossbar 231 is longer than the rear half of the crossbar 233, for the reasons explained below.

[0033] The front half-crossbar 231 has a left end 231A hinged to the left column 27A via a left hinge 232A, which may be defined by a bearing. The axis of the left hinge 232A is parallel to the axis 29A of the central hinge connecting the upper crossbar 23 to the frame 3. Furthermore, the front half-crossbar 231 has a right end 231b hinged to the right column 27B via a right hinge 232B, which may be defined by a bearing. The axis of the right hinge 232B is parallel to the axis 29A of the central hinge connecting the upper crossbar 23 to the frame 3.

[0034] In a specific embodiment, the hinge between the central element 3C and the upper crossbar 23 is defined by two coaxial bearings 31 and 32, which are respectively arranged in front of and behind the central element 32C of the frame 3 relative to the vehicle travel direction defined by arrow F.

[0035] In the illustrated embodiment, as mentioned above, the rear half of the crossbar 233 is shorter than the front half of the crossbar 231, and therefore its left end 233A and right end 233B do not extend to the posts 27A, 27B, and they are not directly connected to the posts 27A, 27B.

[0036] However, the rear half-crossbar 233 and the front half-crossbar 231 are connected to each other to form a single rigid body. In the illustrated embodiment, the front half-crossbar 231 and the rear half-crossbar 233 consist of two mechanical parts that are physically distinct and connected by screws or other connecting devices. However, it is not excluded that two half-crossbars 231 and 233 may be provided in a single workpiece (e.g., a single mechanical component) manufactured, for example, by casting or by removing chips from a single block.

[0037] The lower crossbar 25 is hinged to the central element 3C of the frame 3 at the midpoint 36 of its longitudinal extension (see...). Figure 4 Basically, hinge point 36 defines a central hinge axis 36A, about which the lower crossbar 25 rotates relative to the frame 3. The central hinge axis 36A is located in the vertical center plane of the vehicle in the same manner as axis 29A. The hinge axis 36 extends in the direction of the center plane and is skewed from top to bottom in the rearward direction (arrow B).

[0038] In a specific embodiment, the hinge between the central element 3C and the lower crossbar 25 is defined by two coaxial bearings 37 and 38, which are respectively arranged in front of and behind the central element 3C of the frame 3 relative to the vehicle's direction of travel (arrow F).

[0039] The lower crossbar 25 includes a front half crossbar 251 arranged in front of the central element 3C relative to the vehicle's direction of travel (arrow F) and a rear half crossbar 253 arranged behind the central element 3C.

[0040] For example, especially in Figure 3 As can be seen, in contrast to the semi-crossbars 231 and 233 forming the upper crossbar 23, the front semi-crossbar 251 and rear semi-crossbar 253 of the lower crossbar 25 have the same length, or are either long enough to connect at their ends to the left column 27A and right column 27B of the four-bar linkage 21, respectively. Each semi-crossbar is hinged to the corresponding column by a corresponding hinge, each hinge consisting of, for example, a bearing, such that the linkage between the lower crossbar 25 and the columns 27A and 27B requires four bearings, while the linkage between the upper crossbar 23 and the columns 27A and 27B requires only two bearings.

[0041] More specifically, the front half-crossbar 251 has a left end 251A hinged to the left column 27A via a left hinge 252A defined by a corresponding bearing, and the axis of the left hinge 252A is parallel to the axis 36A of the central hinge that links the lower crossbar 25 to the frame 3. Furthermore, the front half-crossbar 251 has a right end 251B hinged to the right column 27B via a right hinge 252B defined by a corresponding bearing, and the axis of the right hinge 252B is parallel to the axis 36A of the central hinge that links the lower crossbar 25 to the frame 3.

[0042] In the illustrated embodiment, as mentioned above, the rear half-bar 253 has the same length as the front half-bar 251, and therefore its left and right ends (shown as 253A and 253B) are directly hinged to the posts 27A and 27B at hinges 252A and 252B by corresponding hinges defined by corresponding bearings, which are similar to those bearings that define the hinges between the posts 27A and 27B and the front half-bar 251.

[0043] In this configuration, the two right and left ends of the lower crossbar 25 are thus hinged to the columns 27A and 27b via corresponding double right hinges 252B and double left hinges 252A. Each double hinge consists of a pair of bearings, with the first bearing housed in the end of the front half of the crossbar 251 and the second bearing coaxial with the first bearing housed in the end of the rear half of the crossbar 253.

[0044] The rear half-crossbar 253 and the front half-crossbar 251 are further linked to each other to form a rigid body. In the illustrated embodiment, the front half-crossbar 231 and the rear half-crossbar 233 consist of two mechanical parts that are physically distinct and connected by screws or other connecting devices. However, it is not excluded that two half-crossbars 251 and 253 may be provided in a single workpiece (e.g., a single mechanical part manufactured by casting or by removing chips from a single block).

[0045] The resulting four-bar linkage structure 21 is therefore highly durable, and the crossbars are extremely rigid to prevent bending under stresses generated during operation. Simultaneously, the four-bar linkage 21 is lighter and less bulky than prior art four-bar linkages. In fact, the lower crossbar 25 consists of two semi-crossbars (a front semi-crossbar 251 and a rear semi-crossbar 253), on which the stress applied is greater than that applied to the upper crossbar 23. The lengths of these two semi-crossbars allow them to be mechanically linked to the two columns 27A and 27B of the four-bar linkage 21 via bearings. Double hinges, i.e., double bearings between each column 27A and 27B and the two ends of the lower crossbar 25, impart high structural rigidity.

[0046] Considering that one of the two semi-horizontal bars (particularly preferably the rear semi-horizontal bar 233) is shorter and does not reach the hinge axis between the upper horizontal bar 23 and the columns 27A and 27B, the upper horizontal bar 23, which is subjected to less stress, is connected to the two columns 27A and 27B at the two right ends and the two left ends by corresponding hinges corresponding to only one bearing.

[0047] Considering the smaller mass of the upper rear crossbar 233 and the absence of two bearings, this allows for a lighter four-bar linkage 21. The reduction in mass and the decrease in the total number of bearings in the four-bar linkage joints also lowers the cost of the four-bar linkage 21.

[0048] However, the durability and rigidity of the components of the four-bar linkage 21 will not be compromised by such lightening and reduction of the components, especially if the reduction in the bearing and length of one of the two semi-crossbars relates to the upper crossbar 23 subjected to less stress. As provided in the illustrated example, it is even more advantageous that the lightened semi-crossbar is the rear upper crossbar (233) rather than the front upper crossbar (231).

Claims

1. A tilting saddle-type motor vehicle, comprising: frame; Rear drive wheels; Front left steering wheel with left shock absorber; And the front right steering wheel with right shock absorber; The tilting four-bar linkage includes: The upper crossbar is hinged to the central element of the frame at a midpoint; wherein the upper crossbar includes a front half crossbar disposed in front of the central element of the frame and a rear half crossbar disposed behind the central element of the frame; wherein the front half crossbar and the rear half crossbar form a single rigid body through which the central element of the frame extends. A lower crossbar is hinged to the central element of the frame at a midpoint; wherein the lower crossbar includes a front half crossbar disposed in front of the central element of the frame and a rear half crossbar disposed behind the central element of the frame; wherein the front half crossbar and the rear half crossbar of the lower crossbar form a single rigid body, and the central element of the frame extends through the single rigid body of the lower crossbar. A left upright, which is hinged to the left end of the upper crossbar and the left end of the lower crossbar; wherein the front left steering wheel is linked to the left upright so as to rotate about the left steering axis; A right column, which is hinged to the right end of the upper crossbar and the right end of the lower crossbar; wherein the front right steering wheel is linked to the right column so as to rotate about the right steering axis; Its features The first half of the front half of the first horizontal bar in the upper horizontal bar and the second half of the rear half of the first horizontal bar is longer than the second half of the front half of the first horizontal bar, and is directly hinged to the left column via a left hinge and directly hinged to the right column via a right hinge. The second half of the first horizontal bar, in both the front and rear halves, is not directly hinged to the left and right uprights; and The front and rear halves of the second horizontal bar in the upper and lower horizontal bars are both directly hinged to the left column via a left hinge and directly hinged to the right column via a right hinge.

2. The motor vehicle according to claim 1, wherein, The first horizontal bar is the upper horizontal bar.

3. The motor vehicle according to claim 1, wherein, The first half of the first horizontal bar is the front half of the horizontal bar.

4. The motor vehicle according to claim 2, wherein, The first half of the first horizontal bar is the front half of the horizontal bar.

5. The motor vehicle according to claim 1, wherein, Each hinge linking the upper and lower crossbars to the left and right columns includes a corresponding bearing.

6. The motor vehicle according to claim 2, 3 or 4, wherein, Each hinge linking the upper and lower crossbars to the left and right columns includes a corresponding bearing.

7. The motor vehicle according to any one of claims 1-5, wherein, The first horizontal bar's front half and rear half are composed of a single workpiece.

8. The motor vehicle according to any one of claims 1-5, wherein, The first crossbar consists of two parts rigidly connected by a mechanical connecting member: the front half crossbar and the rear half crossbar.

9. The motor vehicle according to any one of claims 1-5, wherein, The front half and the rear half of the second horizontal bar are composed of a single workpiece.

10. The motor vehicle according to any one of claims 1-5, wherein, The front half and the rear half of the second crossbar are composed of two parts rigidly connected by a mechanical connecting member.

11. The motor vehicle according to any one of claims 1-5, wherein, Each of the first and second crossbars is linked to the central element of the frame via a front bearing constrained to the front half of the corresponding crossbar and a rear bearing constrained to the rear half of the corresponding crossbar.

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