Saddle-ride type vehicle with frame having reduced rigidity against yaw movement

Abstract

The present invention relates to a saddle-ride vehicle, preferably an endurance vehicle. The vehicle includes a steering tube to which a steering assembly for controlling a front wheel is rotatably coupled. The vehicle includes a frame (10) having a central portion (12) to which a first end (8A) of a fork (8) is hingedly coupled, the first end (8A) of the fork having a second end (8B) rotatably coupled to a rear wheel (4). The frame includes a front portion (15) extending between the steering tube (11) and the central portion (12). The front portion (15) includes a first frame side portion (15A) and a second frame side portion (15B) spaced apart in a width direction (X) of the vehicle, and is made of a first metal material. The vehicle according to the present invention is characterized by including at least a pair of coupling plates (16A-16B) including a first plate (16A) coupling the engine assembly (2) to the first frame side portion (15A) and a second plate (16B) coupling the engine assembly (2) to the second frame side portion (15B). These plates (16A to 16B) are made of a second metal material having a lower elastic modulus than the first material constituting the frame side portions (15A, 15B) of the front portion (15) of the frame (10).

Description

[Technical Field]

[0001] explanation The present invention relates to the manufacture of saddle-type motorcycles, preferably desert-type, and more generally endurance-type motorcycles, but is not limited thereto, and in particular to saddle-type vehicles having a frame structure that is less stiff against yaw movements of the vehicle than against torsional and bending movements of the same vehicle. [Background technology]

[0002] prior art A two-wheeled endurance vehicle comprises a frame structure including a steerer tube to which a steering assembly that controls the steering wheel or front wheels is pivotally coupled. The frame structure has a central section to which a swing arm that supports the drive or rear wheels is hinged by a pin. Between the central section and the steerer tube extends a forward section of the frame structure, to which an engine is typically coupled that generates drive torque. The drive torque is transmitted to the rear wheels by a mechanical transmission using a chain or transmission shaft. The frame structure is completed by a rear section that extends from the central section toward the rear wheels and which typically supports the vehicle's saddle.

[0003] Patent application EP2818391 relates to a vehicle having a frame structure as described above. In particular, the front of the structure has two frame sides that are substantially mirror-image relative to a vertical plane containing the axis of the steering tube. Each of the frame sides has a main component welded to the steering tube at the front and to a side of the central part of the frame structure at the rear. For each frame side, a reinforcing component is also provided that is connected to the steering tube at the front and to a side of the corresponding main component at the rear so as to remain below the corresponding main component. For each frame side, a connecting component is also provided that extends from the reinforcing component and has a free end to which part of the engine is connected.

[0004] Finally, the front of the frame comprises a transverse element extending between the two frame sides in the width direction of the vehicle, in particular located near the position where each reinforcing component is connected to the corresponding main component of the corresponding frame side.

[0005] In the solution described in EP 2 818 391, the front of the engine is connected to the front of the frame by the above-mentioned connecting components. Instead, the engine is mainly connected to the central part by the same pin that allows the swingarm to rotate. The solution in question also provides a pair of support brackets, each of which is connected to the inside of one of the main components of the front frame side. The support brackets are configured in a V-shape, with the upper part of the support bracket connected to one side of the engine assembly.

[0006] In the aforementioned solution, as well as other conceptually similar solutions, the frame structure is constructed to have the same stiffness against all movements to which the frame, and the motor vehicle in general, is subjected. In particular, the frame structure is typically designed to provide high stiffness against torsional, bending, and yaw movements. The term "torsion" refers to the vibrations experienced by a motorcycle about a longitudinal axis (an axis perpendicular to the axis of rotation of the drive wheels) passing through the center of gravity. The term "bending" refers to vibrations about a transverse axis perpendicular to the longitudinal axis, and the term "yaw" refers to vibrations about a vertical axis passing through the center of gravity of the vehicle.

[0007] The applicant has noted that riders of endurance motorcycles are increasingly demanding that the stiffness of the frame structure against yaw motion be increased, particularly reduced, with respect to stiffness against torsional and bending motion. Summary of the Invention

[0008] overview Therefore, a primary object of the present invention is to provide a saddle-ride type vehicle that makes it possible to overcome the aforementioned limitations and, in particular, meet the needs of riders as described above. In relation to this object, a first object of the present invention is to provide a saddle-ride type vehicle in which the frame structure provides the vehicle with a stiffness against yaw movement that is less than the stiffness against bending and torsion. Another object of the present invention is to provide a saddle-ride type vehicle that is highly reliable and can be easily manufactured at a competitive cost.

[0009] The applicant notes that the stated objects and aims can be achieved by the use of tie plates that indirectly connect the engine assembly to the frame, and by using for these tie plates a material that is less rigid than the material from which the frame is made. In particular, the stated objects and aims are achieved by a saddle-ride type vehicle comprising an engine assembly and a frame to which the engine assembly is connected, said frame comprising: a steering tube to which a steering assembly controlling the front wheels is pivotally coupled; - a central portion to which a first end of a swing arm is hinged, the central portion having a second end pivotally coupled to the rear wheel; a front portion extending between the steering tube and the central portion, the front portion including first and second frame sides spaced apart in a width direction of the vehicle, each frame side being made from a first metal material.

[0010] The vehicle according to the present invention includes at least a pair of connecting plates, where a first plate connects an engine assembly to a first frame side portion and a second plate connects the engine assembly to a second frame side portion, and each of the plates is formed of a second metal material having a lower elastic modulus than the elastic modulus of a first material constituting the frame side portion at the front of the frame.

[0011] Further, in accordance with the present invention, the front of the frame has first sections extending from the steering tube to corresponding second sections, particularly those extending between each first section and the central section of the frame, and these second sections have a mono-component configuration, while each first section has a lattice configuration.

[0012] According to the present invention, each of the pair of connecting plates connects a component of the first portion of the corresponding frame side to a portion of the cylinder head and / or a portion of the engine block of the engine assembly.

[0013] This solution was found to satisfy rider demands: improving vehicle handling without reducing the frame's rigidity against bending and torsion, a requirement especially for off-road motorcycles. In terms of structure and rigidity, the two plates separate the frame from the engine assembly, thereby reducing the vehicle's yaw stiffness.

[0014] According to a possible embodiment, the front part of the frame includes at least a transverse element extending in the width direction of the vehicle, which connects the two sides of the frame, each of the first portions extending from the steering tube to the transverse element, while the second portion extends from the transverse element to the center of the frame.

[0015] According to a preferred embodiment, each frame side is made of steel and each connecting plate is made of an aluminum alloy or other light alloy. Preferably, the second material from which the plates are made has an elastic modulus an order of magnitude lower than that of the first material from which the frame is made.

[0016] According to one embodiment, each of the plates is defined by a body having two major surfaces, the thickness of the body being determined by the distance between the major surfaces, and each plate is coupled to a corresponding frame side and engine assembly such that the thickness of the plate remains oriented substantially in the direction of the width of the vehicle.

[0017] In a preferred embodiment, each frame side of the front portion of the frame has a shape that is substantially a mirror image with respect to a vertical reference plane including the steering axis of the steering assembly. Preferably, each coupling plate is coupled to a corresponding frame side by first fastening means and to the engine assembly by second fastening means, and each coupling plate is arranged in a position that is substantially a mirror image with respect to a vertical reference plane including the steering axis of the steering assembly.

[0018] According to one embodiment, the engine assembly comprises at least one internal combustion engine including an engine block and a cylinder head emerging from said engine block, said engine block being coupled near its rear to a central portion of said frame by a plurality of coupling elements, each coupling plate coupling a corresponding frame side of the front of the frame to the front of the cylinder head and / or engine block.

[0019] In a possible variation of the above embodiment, the vehicle includes a pair of second coupling plates each used to couple the engine assembly to a corresponding second portion of the frame side.

[0020] In a possible embodiment, for each frame side, the corresponding first portion is a first component joined by welding to an upper portion of the steering tube; - a second component, the front end of which is connected to the lower part of the steering tube, also by welding; a third component extending from the rear end of the second component and joining the underside of the first component near the beginning of the second portion; a fourth component that couples the first component and the second component to each other.

[0021] In one embodiment, for each of the frame sides, one of the first coupling plates couples the third component and / or the second component to the cylinder head and / or the engine block of the engine assembly.

[0022] In one possible configuration, each of the first plates has a centrally extending upper section and a lower section, the upper section being secured to the first frame side by a threaded fastening element, and the lower section being secured to the engine assembly by a second fastening element.

[0023] Preferably, the first screw fixation element comprises a first screw fixation element and a second screw fixation element that fixes a corresponding connection plate near a connection area between the third component and the second component of the front first portion of the frame.

[0024] Preferably, the second fixing element comprises a first threaded fixing element and a second threaded fixing element for fixing a corresponding coupling plate to a part of the cylinder head and a part of the front of the engine block of the engine assembly.

[0025] According to a possible embodiment, the vehicle comprises a radiator coupled to the coupling plate so as to occupy a position between the steering assembly and the engine assembly. [Brief explanation of the drawings]

[0026] Drawing List Further features and advantages of the present invention will become more apparent from a consideration of the following detailed description of some preferred, non-exclusive vehicle embodiments, shown by way of non-limiting examples in the accompanying drawings. 1 to 3 show views from different points of view of some components of a saddle-ride type vehicle according to the invention. FIG. 4 is another view of the vehicle shown in FIGS. 3 and 4, in which further components of the vehicle are visible. FIG. 5 is a diagram of a component assembly comprising a frame and a connecting plate of a vehicle engine according to the invention. 6 to 8 are views of the component assembly shown in FIG. 5 from different points of view. FIG. 9 is an enlarged view of the first part of the vehicle shown in FIG. 3; FIG. 10 is an exploded view of the second part of the vehicle shown in FIG. 3, which also comprises the first part shown in FIG. 11A and 11B show a possible embodiment of a coupling plate for a vehicle engine according to the invention. Like reference numbers and letters in the figures identify like elements or components. DETAILED DESCRIPTION OF THE INVENTION

[0027] Detailed Description With reference to the aforementioned figures, the present invention therefore relates to a saddle-type vehicle, in other words any moped or motorcycle with two wheels, with a front wheel and a rear wheel. In the following description, the vehicle 1 is also referred to as a car 1 or a motorcycle 1.

[0028] The motorcycle 1 comprises an engine assembly 2 and a frame 10 to which the engine assembly 2 is coupled. The frame 10 has a steering tube 11 to which a steering assembly 5 that controls a steering wheel 3 (or front wheel 3) is pivotally coupled. The structure of a steering assembly is known to those skilled in the art, but is not relevant to the present invention, so a detailed description thereof will be omitted.

[0029] The frame 10 comprises a central part 12 to which a first end 8A of a swing arm 8 is hinged. A drive wheel 4 (or rear wheel 4) is pivotally connected to a second end 8B of the swing arm 8. According to known technical solutions, and therefore not described in detail, the drive torque generated by the engine assembly 2 is transmitted to the drive wheel 4 by means of a mechanical transmission, for example a chain transmission.

[0030] The frame 10 has a front portion 15 extending between the steering tube 11 and the central portion 12. The front portion 15 includes a first frame side portion 15A and a second frame side portion 15B spaced apart in the width direction of the vehicle. For the purposes of the present invention, the terms "width X," "direction of width X," or "lateral direction" are used to denote a direction substantially parallel to the axis of rotation T of the rear wheels, while the terms "length direction" or "longitudinal direction Y" are used to denote a direction substantially perpendicular to the lateral direction (i.e., perpendicular to said axis of rotation T).

[0031] The two frame sides 15A, 15B of the front part 15 are made of a first metallic material, for example steel, and comprise a number of elements joined together, typically by welding, to obtain a single body.

[0032] According to the present invention, the vehicle 1 comprises at least a pair of connecting plates 16A, 16B, in which a first plate 16A connects the engine assembly 2 to a first frame side 15A, and a second plate 16B connects the engine assembly 2 to a second frame side 15B. According to the present invention, the plates 16A, 16B are formed of a second material having a lower elastic modulus than the first material constituting the two frame sides 15A, 15B.

[0033] The definition of elastic modulus (usually also referred to as Young's modulus) is well known to those skilled in the art and describes the relationship between stress and deformation under uniaxial loading conditions (Hooke's Law) and the elastic behavior of a material.

[0034] For the purposes of the present invention, the expression "plate" is used generically to denote a body having two predominant dimensions (width and length) relative to a third dimension (thickness), the two predominant dimensions defining two main surfaces SP separated by a thickness S (see FIG. 9) of the plate (third dimension).

[0035] Unlike the prior art, in the vehicle 1 according to the invention the engine assembly 2 is therefore not directly connected to the front part 15 of the frame 10, but is indirectly connected thereto by at least a pair of plates 16A, 16B made of a material less stiff than the material used for the frame. The plates 16A, 16B therefore do not represent the only connection interface between the engine assembly 2 and the front part 15 of the frame 10, but due to the different materials make the engine assembly 2 more independent from the frame 10, at least with regard to vibrations caused by yaw movements.

[0036] In particular, for the purposes of the present invention and in order to emphasize the desired effect (reduced stiffness against yaw movements) and to ensure a high degree of stiffness against bending and torsion, it is preferred that the plates 16A, 16B are arranged so that their thickness S (shown in FIG. 9) is oriented substantially in the direction of the width X of the vehicle 1, i.e. so that their main surfaces SP are oriented substantially in the longitudinal direction of the vehicle (i.e. parallel to the longitudinal direction Y).

[0037] Preferably, each of the plates 16A, 16B is connected to the outer part of the corresponding frame side 15A, 15B, i.e., connected so that the two frame sides 15A, 15B are located between the plates in the direction of the vehicle width X. Alternatively, the plates 16A, 16B can be connected at the inner part, i.e., so that they remain contained laterally between the two frame sides 15A, 15B.

[0038] According to a possible embodiment, the two frame sides 15A, 15B are made of steel and the two plates 16A, 16B are made of an aluminum alloy, for example by a casting or forging process. As an alternative to aluminum, the two plates 16A, 16B can also be made of other light alloys, such as magnesium alloys.

[0039] Generally, according to a preferred embodiment, the connecting plates 16A-16B are made of a material having a modulus of elasticity that is an order of magnitude lower than the modulus of elasticity of the material used to manufacture the two sides 15A, 15B of the frame 10.

[0040] 5-9, preferably, the two frame sides 15A, 15B of the front section 15 have a substantially mirror-plane arrangement with respect to a vertical reference plane PV that includes the steering axis 401 (shown in FIG. 2). The expression "steering axis" is used to indicate the axis of rotation created by the steering tube 11 of the steering assembly 5.

[0041] As can be seen from the figures, and in particular from Figure 10 described below, each of the plates 16A, 16B is connected to the corresponding frame side 15A, 15B by first fastening means and to the engine assembly 2 by second fastening means. Preferably, the first and / or second fastening means are of the "screw" type, and this term is used to refer not only to screw elements in the narrow sense but also to any other functionally equivalent fastening elements.

[0042] The two plates 16A, 16B are coupled to the engine assembly 2 at points thereon located within the same half-space as the corresponding frame sides 15A, 15B, said half-space being defined by the vertical plane PV. Essentially, in use, the two plates 16A, 16B are each located within the half-space defined by the vertical plane PV without crossing said plane. Preferably, the two plates 16A, 16B are also located in a substantially mirror-image position relative to the vertical plane PV. Preferably, the first and second fastening means for the first plate 16A are also located in a substantially mirror-image position relative to the positions occupied by the first and second fastening means for the second plate 16B, which positions are always viewed relative to the vertical plane PV.

[0043] Preferably, the engine assembly 2 comprises at least one internal combustion engine 2A that generates a drive torque that is transmitted to the drive wheels 4 by the aforementioned transmission. The internal combustion engine 2A comprises an engine block 21 and a cylinder head 22 emerging above the engine block 21. The term "cylinder head 22" is used to denote the upper part of the engine that encloses the cylinders and incorporates the combustion chambers. For the purposes of the present invention, the term "engine block" is used to denote not only the remainder of the engine assembly 2, i.e., the part about which the drive shaft rotates, but also the other motion-transmitting components between the drive shaft and the transmission to the rear wheels 4. These "transmitting components" therefore include a clutch and a gearbox; as is known, a clutch is interposed between the drive shaft and the gearbox to allow gradual movement and thus enable gear changes.

[0044] According to a preferred embodiment, the rear portion 21B of the engine block 21 of the engine assembly 2 is connected, preferably directly, to the central portion 12 of the frame 10 by a plurality of connecting elements 91, 92, 93. Plates 16A, 16B are used to support the cylinder head 22 of the internal combustion engine 22A and / or the front portion 21A of the engine block 21.

[0045] For the purposes of the present invention, the terms "front" and "rear" used in connection with an end or portion of a structural element of a frame, or a portion of the engine assembly 2, or more generally a component of a vehicle, indicate its orientation relative to the longitudinal direction Y, and therefore whether said portion is oriented towards the front wheels 3 (front) or towards the rear wheels 4 (rear).

[0046] By virtue of the coupling elements 91, 92, 93, the engine assembly 2 remains stably coupled to the central portion 12 of the frame 10, thus maintaining high torsional and bending stiffness. Conversely, due to the effect of the coupling plates 16A, 16B, the engine assembly 2 remains better separated from the front portion 15 of the frame 10 during yaw vibrations, which has been found to translate into easier vehicle controllability for the rider.

[0047] 1 to 4, the frame 10 comprises a rear section 18 extending from the central section 12 towards the rear wheel 4. The function of the rear section 18 is to support a saddle 400 (shown in dashed lines only in FIG. 4) of the motor vehicle 1. One embodiment of the rear section 18 will be briefly described below by discussing FIG. 5, although the configuration of the rear section 18 is not relevant to the present invention.

[0048] According to the present invention, the front portion 15 of the frame 10 comprises first portions 151A, 151B extending from the steering tube 11 and corresponding second portions 152A, 152B extending between the first portions 151A, 151B and the central portion 12 of the frame 10.

[0049] Furthermore, according to the present invention, for each of the frame side portions 15A, 15B, the corresponding first portion 151A, 151B has a substantially mesh or lattice configuration, and therefore, for each first portion 151A-151B, it is possible to identify a plurality of components 51A-51B, 52A-52B, 53A-53B, 54A-54B, which preferably have a tubular shape.

[0050] The second portions 152A-152B have a mono-component configuration, i.e., a single component 55A, 55B, meaning a single box or tubular component having a single component. The second portions 152A-152B extend between the corresponding first portions 151A, 151B and the central portion 12 of the frame 10. Thus, each second portion 152A-152B is defined by a single structural element having a front end 155A, 155B coupled to the structural element of the corresponding first portion 151A, 151B, and a rear end 156A, 156B coupled to the central portion 12 of the frame 10.

[0051] 5 to 8, according to a possible embodiment, the front part 15 of the frame 10 comprises at least a transverse element 15C extending in the direction X of the vehicle and connecting two frame sides 15A, 15B. For each of said frame sides 15A, 15B, a corresponding first portion 151A, 151B extends from the steering tube 11 to the position of the transverse element 15C, and a corresponding second portion 152A-152B extends between the corresponding first portion 151A, 151B and the central part 12 of the frame 10.

[0052] 8, substantially near the longitudinal position of the transverse element 15C, the front part 15 of the frame 10 has its maximum extension in the direction of width X. The first portion 151A of the first frame side 15A and the first portion 151B of the second frame side 15B converge toward the steerer tube 11. Conversely, the second portion 152A of the first frame side 15A and the second portion 152B of the second frame side 15B converge toward the central part 12. However, it can be noted that for each frame side 15A, 15B, the inclination of the first portion 151A, 151B with respect to the vertical plane PV (which contains the steering axis) is greater than the inclination of the corresponding second portion 152A, 152B with respect to the same plane.

[0053] According to a preferred embodiment, the connecting plates 16A, 16B (hereinafter also referred to as "first plates 16A, 16B") connect the engine assembly 2 to the first portions 151A-151B of the corresponding frame sides 15A, 15B of the front portion 15. Preferably, the first plates 16A, 16B connect the structural elements 51A-51B, 52A-52B, 53A-53B, 54A-54B of the first portions 151A, 151B to a portion of the cylinder head 22 and / or a portion of the engine block 21 of the engine assembly 2.

[0054] In a possible embodiment, always visible in the figures, the motor vehicle may also comprise a second pair of connecting plates 17A, 17B (hereinafter also designated using the expression "second plates 17A, 17B") connecting the engine assembly 2, preferably its cylinder head 22, to the second parts 152A, 152B of the corresponding frame sides 15A-15B. Advantageously, the second plates 17A, 17B may be made of a material having a lower modulus of elasticity than the modulus of elasticity of the material constituting the front part 15 of the frame 10.

[0055] Thus, according to the preferred embodiment shown in the figures, it is possible to identify, for each frame side 15A, 15B of the front part 15, a front plate 16A of said first plates 16A, 16B and a rear plate of said second plates 17A, 17B. Overall, this solution provides, for each frame side 15A, 15B, two points of connection with the corresponding part of the engine assembly 2 in the same half-space (identified by the vertical reference plane PV).

[0056] As mentioned above, the two frame sides 15A, 15B of the front part 15 have a substantially mirror-image arrangement with respect to the above-defined vertical reference plane PV (FIGS. 7 and 8). With particular reference to FIGS. 5 and 7, a description of possible, and therefore non-exclusive, embodiments of the first frame side 15A follows. The following is therefore considered to be valid mutatis mutandis for said second frame side 15B.

[0057] The first portion 151A of the first frame side 15A comprises a first upper component 51A joined by welding to the upper portion 11A of the steerer tube 11. The first component 51A is made of a single tubular component together with a component 55A defining a second portion 152A. In particular, the axis of the single tubular component extends on a first inclined plane P1. The other elements of the first portion 151A are located below the first inclined plane P1 (see FIG. 6).

[0058] The first portion 151A also has a second component 52A, the forward end 511 of which is joined by welding to the lower portion 11B of the steerer tube 11. A third component 53A is joined to the aft end 512 of the second component 51B and extends to join the first component 51A at its underside near the point where the single-component second portion 151B begins. The first portion 151A also has a fourth component 54A that joins the first and second components 51A and 52A together. In particular, the fourth component 54A extends substantially between the central portions of the first and second components 51A and 52A.

[0059] According to a possible embodiment, for each of said frame sides 15A, 15B, one of the connecting plates 16A, 16B is connected to the outer part of the third component 53A and / or to the outer part of the second component 52A, preferably at the location where it connects to the third component 53A. In any case, the scope of the invention also includes the possibility of connecting the first plate 16A, 16B to another component of the corresponding first part 151A, 151B.

[0060] According to a possible embodiment (e.g., clearly visible in FIG. 5), the third component 53A and the second component 52A are connected by a sleeve 59. The latter may, for example, consist of a forging connected to each end of the two components 53A, 52A. The sleeve 59 essentially defines the connection between these components 53A, 52A. Preferably, a corresponding connecting plate 16A is connected to the sleeve 59.

[0061] 5 to 8, in a preferred embodiment, the central portion 12 of the frame 10 has a first flank 121 and a second flank 122 that face each other. These flanks 121, 122 are formed of plate-like bodies and are connected by a lower pin 31 and an upper pin 32 that extend in the direction of the width X of the vehicle. With respect to the above-mentioned vertical plane PV, the first flank 121 is located on the same side as the first frame side portion 15A of the front portion 15, and the second flank 122 is located on the same side as the second frame side portion 15B. The first frame side portion 15A and the second frame side portion 15A are connected to the upper pin 32 of the central portion 12 in the vicinity of the first end 32A and the second end 32B of the upper pin 32, respectively, preferably by welding.

[0062] According to one embodiment (as can be seen in particular in Figures 1, 2 and 4), the rear portion 21B of the engine block 21 of the engine assembly 21 is connected to the frame 10 and the central portion 12 by a first coupling element 91 that coincides with the swing arm 8, i.e., the swing pin of the rear wheel 4. The rear portion 21B is also connected to each side 121, 122 of the central portion 21 by a second coupling element 92 and a third coupling element 93 that are respectively located above or below the position of the first coupling element 91. Preferably, the second coupling element 92 and the third coupling element 93 are defined by studs, pins or other functionally equivalent elements.

[0063] 5 and 6, the first flank 121 has a first section 121A from whose upper end the upper pin 32 extends, and a second section 121B extending below the first section 121A. The aforementioned lower pin 31 extends from the lower end of the second section 121B. The second section 121B has a foot 125 extending toward the front wheel 3. This foot 125 may be joined to another portion of the second section 121B or may be formed integrally therewith.

[0064] The second coupling element 92 is vertically contained between the first coupling element 91 and the upper pin 32 and is located longitudinally further forward than the first coupling element 91 and towards the front wheel. The third coupling element 93 is located vertically below that of the swing arm 8 and longitudinally further forward than that of the first coupling element 91.

[0065] Overall, therefore, three connection points (91, 92, 93) to the part 21B of the engine block 21 are advantageously provided for each flank 121, 122 of the central part 12. This situation ensures that the vehicle has the necessary torsional and bending stiffness. Meanwhile, the support of the front part 21A of the engine assembly 2 (cylinder head 22 and / or engine block 21) is assigned to the first plates 16A, 16B and, if present, also to the second plates 17A, 17B. According to the principles outlined above, due to their structure and mechanical properties (materials), at least the first plates 16A, 16B, and possibly also the second plates 17A, 17B, make the frame-engine assembly system less stiff with respect to yaw movements.

[0066] As mentioned above, Figures 5-8 also show possible, and therefore non-exclusive, embodiments of the rear portion 18 of the frame 10, which comprises a first rear frame side 18A and a second rear frame side 18B respectively connected to a first flank 121 and a second flank 122 of the central portion 12 (see Figure 5). The two rear frame sides 18A, 18B are connected to each other in the width direction of the vehicle by one or more lateral connecting elements 19. In general, the rear portion 18 can be made from multiple welded tubular components and can be made from the same material as the other portions 12, 15 of the frame 10 are made from.

[0067] Each rear frame side 18A, 18B includes an upper element 181A, 181B and a lower element 182A, 182B joined to the upper element by a joining element 183A, 183B. The upper element 181A, 181B is joined, preferably welded, to the upper pin 32 of the central section 12 at a location opposite to where the corresponding frame side 15A, 15B of the front section 15 is welded. Meanwhile, the lower element 182A, 182B extends from the corresponding side 121, 122 of the central section 12 (preferably welded between the corresponding side regions 121A, 121B) below the first upper element 181A, 181B before joining near the protruding ends 190A, 190B.

[0068] 9 to 11 show preferred embodiments of the first plates 16A, 16B and their fastening means. In the following, to better explain the mounting, the expression "right plate 16A" will be used to refer to the plate connected to the first frame side 15A located on the right side of the vertical reference plane PV with respect to an observation point at the front of the vehicle (the same observation point as used in FIG. 7). Similarly, the expression "left plate 16B" will be used to refer to the plate connected to the second frame side 15B located on the other side of the same vertical plane PV.

[0069] The detailed view shown in Figure 9 shows the installation position of the right plate 16A, in which it is connected to at least one component 52A, 53A of the first portion 151A of the first side of the frame 15A by first fastening means 411A-412A, and to the cylinder head 22 and the front portion 21A of the engine block 21 by second fastening means 421A-422A. The perspective view shown in Figure 9 shows the configuration of the right plate 16A, in particular its thickness S, which is significantly reduced relative to the main surface SP of the plate. Figure 9 also shows the orientation of the right plate so that the thickness S is in the direction of the width X of the vehicle 1.

[0070] FIG. 11A shows only the right plate 16A from an observation point corresponding to FIG. 1, while FIG. 11B shows the left plate (not shown in FIG. 1). While the right plate 16A will be described below, it should be understood that this description is also valid for the left plate 16B. Therefore, components shown in FIG. 11A with reference to the right plate 16A are also shown in FIG. 11B with the suffix B, since they refer to the left plate 16B.

[0071] The right plate 16A includes an upper section 171A and a lower section 172A, with a central section 173A extending therebetween. The upper section 171A is fixed to the first frame side portion 15A by first fastening means 411A-412A, and the lower section 172A is fixed to the engine assembly 22 by second fastening means 421A-422A.

[0072] Preferably, the first fastening means 411A-412A comprise a plurality of screw fastening elements (clearly visible in FIG. 10) passing through corresponding holes 71A made through the upper section 171A of the right plate 16A. Similarly, the second fastening means 421A-422A comprise a plurality of screw fastening elements passing through corresponding holes 72A made through said lower section 172A.

[0073] According to a preferred embodiment, the first fixing elements 411A, 412A comprise a first screw fixing element 411A and a second screw fixing element 412A that secure the right plate 16A to the first frame side first portion 151A near the joint area between the third component 53A and the second component 52A. In the illustrated embodiment, this joint area is defined by the aforementioned sleeve 59 connecting the ends of the components 52A, 53A. This sleeve 59 forms a type of connection interface between the first portion 151A of the first frame side 15A and the right plate 16A, thereby defining a seat 58A that is used to screw in the opposing fixing elements 411A, 412A.

[0074] Furthermore, according to one embodiment, the second fixing elements 421A to 422A include a first screw fixing element 421A and a second screw fixing element 422A that fix the right plate 16A to the portion 221 of the cylinder head 22 and the portion 222A of the front portion 21A of the engine block 21. Alternatively, the two screw fixing elements 421A, 422A may connect the lower section 172A of the right plate 16A only to the cylinder head 22 or only to the front portion 21A of the engine block 21.

[0075] In the embodiment shown in FIG. 11A, the three sections 171A, 172A, and 173A of the right plate 16 have a substantial parting line configuration such that, in use, the upper section 171A is positioned more forward than the lower section 172A. In particular, in use, the upper section extends “forward” relative to the central section (i.e., toward the steering wheel 3) and the lower section 172A extends rearward (i.e., toward the drive wheel 4). Extending between the upper section 171A and the central section 173A is an elbow 175A that defines a seat for a screw fastening element 411A that couples the right plate 16A to the third component 53A of the first frame side 15A. As can be seen in FIG. 1, the elbow 175 also configures the plate 16A, following its fastening, as a sort of extension toward the bottom of the second component 52A.

[0076] As mentioned above, the left plate 16B has substantially the same structure as that of the right plate 16A, while the manner in which the plates are fixed to the front portion 15 of the frame 10 and / or the engine assembly 2 also remains the same, as can be seen in Figure 10. Accordingly, in this figure too, the numerical references used for the configuration and mounting method of the left plate 16B are denoted with the suffix B instead of A.

[0077] 4, the first plates 16A, 16B are coupled to the corresponding frame sides 15A, 15B in such a way that the cylinder head 22 of the engine assembly 2 remains substantially configured in the longitudinal direction between the position of the plates and the central part 12 of the frame 10. Thus, in the space between the steering assembly 5 and the first plates 16A, 16B, a radiator 200 is arranged, as known to those skilled in the art, to be used for cooling the engine assembly 2.

[0078] According to the embodiment shown in Figure 4, the radiator 200 is coupled to the first connecting plates 16A, 16B and is supported by the plates. As can be seen in Figures 11A and 11B, the first plates 16A, 16B have connecting ends 191A, 191B which, in use, extend towards the front wheels 3. Suitable fastening means 201 allow a stable coupling of the radiator 200 to the first plates 16A, 16B.

[0079] 4, the first plates 16A, 16B can also advantageously provide a fixing point for the fuel tank 300 of the vehicle 1. Referring again to Figures 11A, 11B, the first plates 16A, 16B preferably comprise a perforated end 73A, 73B to which the fuel tank 300 is fixed by further screw fixing means 202. Preferably, for each plate 16A, 16B, this perforated end 73A, 73B coincides with an end of the upper section 171A, 171B of the same plate.

[0080] Thus, in a generally possible embodiment, plates 16A, 16B are multifunctional and can be used not only to support engine assembly 2 but also to connect other vehicle components that function with engine assembly 2 (e.g., radiator 200 and fuel tank 300).

[0081] The above-mentioned technical solutions fully achieve the preset aims and objectives. In particular, the use of connecting plates that connect the sides of the frame to the front of the engine assembly makes it possible to have a vehicle in which the frame still offers strong resistance to twisting and bending, but low resistance to yaw movements, thereby favoring vehicle maneuverability by the rider.

Claims

1. The present invention comprises an engine assembly (2) and a frame (10) to which the engine assembly (2) is coupled, the frame (10) comprising: - a steering tube (11) to which a steering assembly (5) controlling the front wheels (3) is pivotally coupled; - a central portion (12) to which a first end (8A) of a swing arm (8) is hinged, the first end (8A) of the swing arm having a second end (8B) pivotally connected to the rear wheel (4); a front portion (15) having a first frame side portion (15A) and a second frame side portion (15B) spaced apart in a direction of a width (X) of the vehicle, the frame side portions (15A, 15B) being formed from a first metallic material having a first modulus of elasticity, the front portion (15) extending between the steering tube (11) and the central portion (12); at least one pair of connecting plates (16A, 16B) in which a first plate (16A) connects the engine assembly (2) to the first frame side (15A) and a second plate (16B) connects the engine assembly (2) to the second frame side (15B); the plates (16A, 16B) are formed of a second metal material having a second elastic modulus lower than the first elastic modulus of the first metal material constituting the frame side portions (15A, 15B) of the front portion (15) of the frame (10); the front portion (15) of the frame (10) comprises first portions (151A, 151B) extending from the steering tube (11) and corresponding second portions (152A, 152B) extending between the first portions (151A, 151B) and the central portion (12) of the frame (10); the second portion (152A, 152B) has a mono-component configuration and the first portion (151A, 151B) has a lattice configuration; each plate of the pair of plates (16A-16B) connects a component (51A-51B, 52A-52B, 53A-53B, 54A-54B) of the first portion (151A-151B) of the corresponding frame side (15A, 15B) to a portion of the cylinder head (22) and / or a portion of the engine block (21) of the engine assembly (2); The vehicle (1) further comprises a pair of coupling plates (17A, 17B) made of a material having a lower elastic modulus than the first elastic modulus, which are used to couple the engine assembly (2) to the second portions (152A, 152B) of the corresponding frame sides (15A, 15B), respectively. A saddle-type vehicle (1).

2. 2. The vehicle (1) of claim 1, wherein the front part (15) of the frame (10) comprises at least a transverse element (15C) extending in the direction of the width (X) of the vehicle and connecting the two frame sides (15A, 15B), the first part (151A, 151B) extending from the steering tube (11) to the transverse element (15C), and the second part (152A, 152B) extending from the transverse element (15C) to a central part (12) of the frame (10).

3. 3. A vehicle (1) according to claim 1 or 2, wherein the frame sides (15A, 15B) are made of steel and the plates (16A, 16B) are made of an aluminium alloy.

4. 4. A vehicle (1) according to any one of claims 1 to 3, wherein each of the plates (16A, 16B) is defined by a body with two main surfaces, the thickness of the body being substantially the distance between the main surfaces, and each of the plates (16A, 16B) is coupled to the corresponding frame side (15A, 15B) and engine assembly (2) such that the thickness of the plate remains substantially oriented in the direction of the width (X) of the vehicle.

5. 5. The vehicle (1) according to claim 1, wherein the frame sides (15A, 15B) of the front part (15) have an arrangement that is substantially mirror-plane with respect to a vertical reference plane (PV) that contains a steering axis (401) for the steering assembly (5).

6. 6. A vehicle (1) according to any one of claims 1 to 5, wherein each of the plates (16A, 16B) is connected to a corresponding frame side (15A, 15B) by a first fastening means and to the engine assembly (2) by a second fastening means, and the plates (16A, 16B) are arranged in a substantially mirror-image position with respect to a vertical reference plane (PV) containing a steering axis (401) for the steering assembly (5).

7. 7. The vehicle (1) according to any one of claims 1 to 6, wherein the engine assembly (2) comprises at least one internal combustion engine (2A) including an engine block (21) and a cylinder head (22) emerging from the engine block (21), the engine block (21) being connected to the central part (12) of the frame (10) near a rear part (21B) of the engine block (21) by a plurality of connecting elements (91, 92, 93), and each plate of the pair of plates (16A-16B) connecting a corresponding frame side part (15A, 15B) of the front part (15) to the cylinder head (22) and / or the front part (21A) of the engine block (21).

8. The first portion (151A, 151B) is - a first component (51A) connected to the upper part (11A) of said steering tube (11) by welding; - a second component (52A) connected at its front end (511) to the lower part (11B) of said steering tube (11), also by welding; a third component (53A) extending from the rear end (512) of the second component (51B) and coupled to the underside of the first component (51A) near the beginning of the second portions (152A, 152B); - a fourth component (54A) connecting the first component (51A) and the second component (52A) to each other.

9. 9. The vehicle (1) according to claim 8, wherein for each of the frame sides (15A, 15B), one of the plates (16A-16B) connects the third component (53A, 53B) and / or the second component (52A, 52B) to the cylinder head (22) and / or the engine block (21) of the engine assembly (2).

10. 10. The vehicle (1) according to any one of claims 6 to 9, wherein each of the plates (16A, 16B) comprises an upper section (171A, 171B) and a lower section (172A, 172B) with a central section (173A, 173B) extending therebetween, the upper sections (171A, 171B) being fixed to the first frame side (15A) by upper section screw fixing elements (411A to 412A, 411B to 412B), and the lower sections (172A, 172B) being fixed to the engine assembly (2) by lower section screw fixing elements (421A to 422A, 421B to 422B).

11. The vehicle (1) according to claim 10, which is dependent on claim 8, wherein the upper section screw fixing elements (411A to 412A, 411B to 412B) comprise first upper section screw fixing elements (411A, 411B) and second upper section screw fixing elements (412A, 412B) that fix plates (16A, 16B) corresponding to the joint region between the third component (53A, 53B) and the second component (52A, 52B).

12. 12. The vehicle (1) according to claim 10 or 11, wherein the lower section screw fixing elements (421A-422A, 421B-422B) comprise first lower section screw fixing elements (421A, 421B) and second lower section screw fixing elements (422A, 422B) that fix corresponding plates (16A, 16B) to the portions (221A, 221B) of the cylinder head (22) and the portions (222A-222B) of the front portion (21A) of the engine block (21).

13. 13. The vehicle (1) according to any one of claims 1 to 12, further comprising a radiator (200) coupled to the plates (16A, 16B) so as to occupy a position between the steering assembly (5) and the engine assembly (2).

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