Saddle-mounted hybrid propulsion vehicle

Abstract

The present invention relates to a straddle-type vehicle, motorcycle, or motorbike including a frame (2), at least one steering wheel (3) rotatably connected to the frame, and a single drive wheel (4). The vehicle further includes a motor assembly (10) and a power transmission unit (T) mechanically connecting the motor assembly (10) to the drive wheel. The motor assembly includes a heat engine (MT) having a crankshaft (11), an electric machine (E) having a stator (S) and a rotor (R), and a clutch (C) having a drive shaft (C1) and a driven shaft (C2). The motor assembly (10) further includes a gearbox (G) with an input shaft (111) and an output shaft (112). According to the invention, the crankshaft (11) of the heat engine (MT), the rotor (R) of the electric machine (E) and the two shafts (C1, C2) of the clutch are coaxial so as to rotate around a common axis of rotation (101) parallel to the longitudinal direction (Y) of the vehicle and parallel to the axis of rotation of the output shaft (112) of the gearbox (G).

Description

Technical Field

[0001] The present invention pertains to the field of manufacturing saddle - type motorcycles having two or three wheels, with only one wheel being the drive wheel. In particular, the present invention relates to a saddle - type hybrid propulsion vehicle, i.e., a vehicle including a motor assembly having a heat engine and a reversible electromechanical machine, where the reversible electromechanical machine can be used as an electric motor to increase the torque available at the drive wheel or as a generator to recharge a battery assembly connected to the electromechanical machine.

Background Art

[0002] In recent years, two - or three - wheel hybrid propulsion motorcycles with an electric machine added to a normal internal combustion engine have been proposed. The purpose of this type of propulsion is, substantially, to utilize the internal combustion engine in a highly efficient state, recover energy by the electric machine during deceleration or braking, and in some cases use only the electric machine as the propulsion. Generally, hybrid propulsion aims to reduce the emissions of pollutants associated with the operation of the internal combustion engine.

[0003] Among hybrid propulsion, a first configuration, also called "series hybrid", is known, where the heat engine is used to rotationally drive the rotor of a current generator, and the current generator recharges a battery assembly. The latter powers an electric motor, which provides propulsion force to the drive wheels of the motorcycle. Thus, in this case, the propulsion force is purely electrical, and the heat engine is used only to recharge the battery and can thus operate under optimal conditions.

[0004] A configuration called "parallel hybrid" is also known, where the drive wheels can be operated by both the heat engine and the electric motor.

[0005] An example of a hybrid motor cycle is described in International Publication No. WO 2004 / 054836, and this type of propulsion is used in open frame motor cycles (scooters). In particular, this solution provides a propulsion assembly that includes a heat engine, an electric motor, and a generator. A centrifugal clutch is operably disposed between the heat engine and the electric motor. The drive shaft of the centrifugal clutch is connected to the crankshaft of the heat engine by a continuously variable transmission (CVT), and the driven shaft of the centrifugal clutch is connected to the rotor of the electric motor. Finally, this rotor is connected to the drive wheels by a reduction gear.

[0006] In the propulsion assembly described in International Publication No. WO 2004 / 054836, when the electric motor is off, the propulsion force is provided only by the heat engine. Conversely, when only the electric motor is powered and the heat engine is off, the propulsion force is purely electrical. When both the heat engine and the electric motor operate simultaneously, the propulsion assembly forms a parallel hybrid, and in the low rotation range of the heat engine, the propulsion of the drive wheels depends only on the electric motor, and the heat engine is used to recharge the battery via the generator.

[0007] Therefore, the above technical solution provides for the transmission (via the CVT) of movement from the drive shaft to another shaft to which an electromechanical clutch and a rotor are attached. In particular, the clutch and the electric motor are disposed at a position substantially close to the drive wheels.

[0008] Other examples of hybrid propulsion are described in US Patent Application Publication No. 2013 / 00818985, where the hybrid propulsion is applied to a closed-frame motorcycle. According to this solution, the electric motor is mounted along an axis that is at a height lower than the height of the shaft of the heat engine relative to the ground. In this case, the propulsion assembly also includes a gearbox having an input shaft that rotates around an axis parallel to and spaced from the rotational axes of the shaft of the heat engine and the rotor of the electric motor. The gearbox further includes an output shaft connected to the drive wheels by a power transmission unit. The motor assembly further includes a first clutch, the drive shaft of which is connected to the shaft of the heat engine by a mechanical power transmission device, and the driven shaft of the clutch is integral with the input shaft of the gearbox. The second clutch further includes a drive shaft connected to the rotor of the electric motor by a second power transmission device, and the drive shaft is connected to the input shaft of the gearbox. By means of the two clutches, the heat engine and the electric motor can be connected to or disconnected from the input shaft of the gearbox. When both are connected, the propulsion assembly operates according to the parallel hybrid mode. When the first clutch is connected and the second clutch is disengaged, drive torque is generated only by the heat engine. Conversely, when the first clutch is disengaged and the second clutch is connected, drive torque is generated only by the electric motor. By disconnecting the first clutch and simultaneously turning on the generator, operation in the series hybrid mode is established instead.

[0009] The applicant has noticed that the above-described technical solution, like other conceptually similar solutions, has several drawbacks, particularly due to the mutual arrangement of the heat engine and the electric motor that constitutes the hybrid propulsion. In particular, the current configuration of the propulsion assembly is particularly complex and bulky, making its manufacture and installation difficult. These aspects clearly affect the final manufacturing cost. At the same time, the current configuration of the propulsion assembly does not seem to be very advantageous in relation to the inspection and / or maintenance operations that may be performed on the vehicle. SUMMARY OF THE INVENTION

[0010] Accordingly, the main object of the present invention is to provide an effective hybrid propulsion vehicle to replace known vehicles. In this regard, a first object is to provide a hybrid propulsion motorcycle in which the motor assembly is particularly compact and can be easily attached to the frame. Another object of the present invention is to provide a hybrid propulsion motorcycle that is reliable and can be easily manufactured at a competitive cost.

[0011] The applicant has confirmed that the above problems and objectives can be achieved by arranging the heat engine such that the crankshaft rotates coaxially with the rotor of the reversible electric machine and coaxially with the (driving and driven) shafts of the clutch. In particular, the present invention relates to a saddle-type vehicle comprising a frame, at least one steering wheel rotatably connected to the frame, a single drive wheel, a motor assembly, and a power transmission unit for mechanically connecting the motor assembly to the drive wheel. The motor assembly comprises · a heat engine including a crankshaft, · an electric machine including a stator and a rotor, · a clutch including a driving shaft and a driven shaft, · a gearbox including an input shaft and an output shaft and is provided with.

[0012] According to the present invention, the crankshaft, the rotor, the driving shaft, and the driven shaft are coaxial so as to rotate around a common axis of rotation. Further, the common axis of rotation is parallel to the axis of rotation of the output shaft of the gearbox and substantially parallel to the longitudinal direction.

[0013] According to the first embodiment, the crankshaft of the heat engine is integral with the rotor of the electric machine and the driving shaft of the clutch. Further, the input shaft of the gearbox is connected to the driven shaft of the clutch, and the output shaft is connected to the drive wheel via the power transmission unit.

[0014] According to one embodiment, the electromechanical machine is disposed between the heat engine and the clutch such that the rotor is connected to the crankshaft on a first side and to the drive shaft of the clutch on a second side.

[0015] According to another embodiment, instead of the last-described embodiment, the heat engine is disposed between the electromechanical machine and the clutch such that the crankshaft is connected to the rotor of the electromechanical machine on a first side and to the drive shaft of the clutch on a second side.

[0016] According to still another embodiment, the clutch is disposed between the heat engine and the electromechanical machine, the drive shaft of the clutch is integral with the crankshaft of the heat engine, and the drive shaft of the clutch is integral with the rotor of the electromechanical machine. In a possible variant, the input shaft of the gearbox is connected to the rotor of the electromechanical machine and the output shaft is connected to the drive wheels via the power transmission unit.

[0017] In another embodiment, · the drive shaft of the clutch is integral with the crankshaft of the heat engine and the driven shaft of the clutch is integral with the input shaft of the gearbox, · the output shaft of the gearbox is connected to the rotor of the electromechanical machine, · the rotor of the electromechanical machine is connected to the drive wheels via the power transmission unit.

[0018] In a possible variant, the power transmission unit includes a power transmission shaft connected to the output shaft of the gearbox and a power transmission module that transmits the movement of the power transmission shaft to the drive wheels.

[0019] Further features and advantages of the present invention will become more apparent from the following detailed description of some non-exclusive but preferred vehicle embodiments provided for illustrative purposes and using the accompanying drawings.

Brief Description of the Drawings

[0020]

Figure 1

Figure 2

Figure 3

Figure 4

Figure 5

Figure 6

Mode for Carrying Out the Invention

[0021] Referring to the above drawings, the present invention thus relates to a saddle-type vehicle having a hybrid propulsion force. For the purposes of the present invention, the term "saddle-type vehicle" shall mean any motorcycle or motorbike having two or three wheels.

[0022] FIG. 1 is a schematic view of a vehicle 1 according to the present invention, and the vehicle 1 includes a frame 2 having a front carriage portion 2A that supports one or two steering wheels 3 in any case. The frame 2 further includes a rear carriage portion 2R that supports only the drive wheels. Thus, the term "drive" means a single wheel of the vehicle 1 to which the rotational torque generated by the motor assembly 10 is transmitted.

[0023] The frame 2 of the vehicle 1 supports a motor assembly 10 that is mechanically connected to the drive wheels 4 via a power transmission unit T. The power transmission unit T can have various configurations and generally consists of a series of motion transmission members that transmit the torque generated by the motor assembly 10 to the drive wheels 4, rotate the drive wheels 4, and ultimately move the vehicle forward. The vehicle 1 extends mainly along the longitudinal direction Y (or longitudinal axis Y) that substantially coincides with the longitudinal direction of the vehicle itself, i.e., the front-rear direction of the vehicle. In practice, the longitudinal direction is the front-rear direction that is substantially perpendicular to the rotation axis of the drive wheels 4.

[0024] Figures 2 - 5 are schematic views of possible embodiments of the motor assembly 10 of the vehicle 1 according to the present invention. In each case, the motor assembly 10 includes a heat engine MT and a reversible electromechanical machine E, i.e., an electromechanical machine that can operate either as an electric motor or a current generator.

[0025] The heat engine MT includes a crankshaft 11 that is rotated by the conversion of the translational movement of one or more pistons in the cylinder, caused by the combustion process occurring in the cylinder, by means of a slider-crank mechanism, based on principles well known to those skilled in the art.

[0026] The operation of the reversible electromechanical machine E operably connected to the battery assembly B is also known to those skilled in the art. In the first operating mode, the electromechanical machine E operates as a "motor" and converts the input electrical energy provided at the terminals of the stator S into mechanical force available at the rotor R. In the second operating mode, the electromechanical machine E operates as an "alternator / generator" and converts the rotational mechanical energy of the rotor R into electrical energy, which is preferably stored in the battery assembly B.

[0027] In the vehicle 1 according to the present invention, the motor assembly 10 further includes a clutch C that, as is known to those skilled in the art, connects two shafts in response to a command so as to enable or, in some cases, adjust the transmission of rotational motion from one shaft to the other. In any case, for the purposes of the present invention, the clutch C includes a drive shaft C1 integrally connected to at least one first connection element C11 and a driven shaft C2 integrally connected to at least one second connection element C12. The clutch C includes actuating means (not shown) for bringing the connection elements C11, C12 into contact with each other to transmit motion from the drive shaft C1 to the driven shaft C2. Still within the framework of the present invention, the clutch C may be a "dry" or "oil bath" type, or otherwise a centrifugal clutch. A torque converter typically used in an automatic gearbox, or more generally, any other system adapted to perform the "clutch" function known to those skilled in the art as described above, is also included in the definition of the clutch.

[0028] According to the present invention, in the vehicle 1, the motor assembly 10 is configured such that the crankshaft 11 of the heat engine MT, the rotor R of the electromechanical machine E, and the two shafts of the clutch C (i.e., the drive shaft C1 and the driven shaft C2) all rotate around a common axis of rotation 101. In other words, the rotating elements (11, R, C1, C2) of the motor assembly 10 are arranged in a row so as to form a row of components (M, E, C) extending along a common axis.

[0029] According to a first embodiment of the motor assembly 10 schematically shown in FIG. 2, the crankshaft 11 of the heat engine MT is integral with the rotor R of the electromechanical machine E and the drive shaft C1 of the clutch C. Therefore, the crankshaft 11, the rotor R, and the drive shaft C1 rotate at the same speed around the common axis of rotation 101.

[0030] In this embodiment, the motor assembly 10 further includes a gearbox G disposed between the clutch C and the power transmission unit T. According to well-known principles, the gearbox G can be operated by an input shaft 111 and an output shaft 112, as well as a lever or an electronic system, and is operably disposed between the two shafts 111, 112, and further includes a plurality of gears (not shown) for changing the speed of the output shaft 112 relative to the speed of the input shaft 111. In this embodiment (Figure 2), the input shaft 111 is connected to the driven shaft C2 of the clutch C, and the output shaft 112 is connected to the power transmission unit T.

[0031] In the schematic diagram of Figure 2, as well as in the schematic diagrams of Figures 3 and 4, the output shaft 112 of the gearbox G is coaxial with the input shaft 111. However, based on the configuration of the gearbox G, the two shafts 111, 112 can also have a non-coaxial arrangement.

[0032] In the second embodiment of the motor assembly 10 shown in the figure of Figure 3, the crankshaft 11, the rotor R, and the drive shaft C1 are still integrated with each other, but the positions of the heat engine MT and the electromechanical machine E are reversed compared to the figure of Figure 2. Specifically, the heat engine MT is operably disposed between the electromechanical machine E and the clutch C along the common rotation axis 101. Therefore, the crankshaft 11 is connected to the rotor R on the first side and the drive shaft C1 of the clutch C on the second side.

[0033] In both of the described configurations (Figures 2 and 3), since the rotor R is integrated with the crankshaft 11, the electromechanical machine E can be used as a "motor" for starting the heat engine MT. Preferably, the heat engine MT is provided with a decompression device for communicating the cylinder with the external environment during the compression and expansion stages, thereby reducing the mechanical torque to be provided by the electromechanical machine for starting.

[0034] Continuing to refer to FIGS. 2 and 3, during the acceleration phase of the vehicle 1, the electromechanical machine 10 can be advantageously used to increase the torque generated by the heat engine MT. In this case, the windings of the stator S are powered by the battery assembly B.

[0035] Alternatively, during the acceleration phase, torque can be provided to the drive wheels 4 by the heat engine MT only. In this case, no power is supplied to the windings of the stator S of the electromechanical machine E, and the rotor R is rotationally driven only by the crankshaft 11 of the heat engine 1 and is in an "idle state" relative to the stator S.

[0036] Continuing to refer to the schematic diagrams of FIGS. 2 and 3, during the constant-speed driving phase, the electromechanical machine E can operate as a "generator" to recharge the battery assembly B. Alternatively, in the driving state, it is possible not to supply power to the windings of the stator S of the electromechanical machine E, and as a result, the rotor R rotates relative to the stator S without generating an electrical effect.

[0037] Finally, also during the braking phase of the vehicle, the electromechanical machine E can remain off or operate as a generator to recharge the battery assembly B. Thus, generally, the electromechanical machine E can be turned on or off in different driving phases (acceleration, constant speed, braking) of the vehicle based on the settings of the control unit ECU of the machine itself. In this regard, for the sake of simplicity, the control unit ECU is shown only in FIG. 2, but it is understood that such a unit (ECU) can be present in any of the embodiments shown and described herein to enable the electromechanical machine to operate as an electric motor, as a generator / alternator, or to remain off.

[0038] In the embodiment schematically shown in FIG. 2, the motor assembly 10 is attached such that the rotation axis 101 is substantially parallel to the longitudinal axis of the vehicle 1 (see the schematic view of FIG. 6), so that the heat engine MT can be cooled better. In this case, a radiator for cooling the heat engine MT can be easily attached to the heat engine MT from the front.

[0039] Compared with the embodiment of FIG. 2, the arrangement of FIG. 3 allows for a simpler electrical connection, taking into account possible arrangements of the battery assembly B instead.

[0040] According to a possible configuration effective for both embodiments shown in FIGS. 2 and 3, the heat engine MT and the electromechanical machine E can be arranged inside a common crankcase, in which the clutch C can also be optionally arranged to form a single assembly that can be more easily attached to the frame 2 of the vehicle 1.

[0041] According to another embodiment of the motor assembly 10 shown in FIG. 4, the clutch C is operably arranged between the heat engine MT and the electromechanical machine E along a common rotation axis 101. Specifically, the drive shaft C1 of the clutch C is integral with the crankshaft 11 of the heat engine MT, and the driven shaft C2 is integral with the rotor of the electromechanical machine E. Also in this embodiment, the motor assembly 10 includes a gearbox G in which the input shaft 111 is integral with the rotor R and the output shaft 112 is instead connected to the power transmission unit T.

[0042] When the clutch C operates, that is, when the connecting elements C1, C12 of the clutch C are connected, the crankshaft 11 of the heat engine MT is rotatably integrated with the rotor R of the electromechanical machine E. Therefore, the torque generated by the heat engine MT is transmitted to the drive wheels 4. Such torque can be provided alone or, alternatively, can be complemented by turning on the electromechanical machine E in the "motor" operating mode to increase the thrust (boost).

[0043] Instead, when the clutch C is turned off, i.e., when the two connecting elements C11 and C12 are disconnected, the heat engine MT no longer provides driving force. Therefore, the driving force of the drive wheels 4 can be provided only by the electromechanical machine E via the gearbox G and the power transmission unit T.

[0044] Therefore, in this embodiment, the vehicle 1 can have either pure electric propulsion (with the clutch C disengaged) or hybrid propulsion (with the clutch C engaged and the electromechanical machine turned on as a motor). In the case of pure electric propulsion, the gears of the gearbox G can be advantageously used to climb slopes.

[0045] Compared with the figure of FIG. 4, in the embodiment schematically shown in FIG. 5, the electromechanical machine E is operably arranged between the power transmission unit T and the gearbox G along a common rotation axis 101. In other words, the gearbox G is arranged between the clutch C and the electromechanical machine E. Specifically, the input shaft 111 of the gearbox G is connected to the driven shaft C2 of the clutch C, and the output shaft 112 is connected to one side of the rotor R of the electromechanical machine E. The power transmission unit T is instead connected to the other side of the rotor R. Therefore, in this embodiment, the gear G is active only when the clutch C is engaged, i.e., when all or part of the driving force is provided by the heat engine MT. Therefore, when the propulsion is purely electric, the gears of the gearbox G are not used.

[0046] Advantageously, the possible embodiments schematically shown in FIGS. 4 and 5 enable the electromechanical machine E to be used as a "motor" to inertially start the heat engine MT. For this start-up, it is necessary that the clutch connecting elements C11 and C12 are first disconnected. In this state, the vehicle 1 is moved by pure electric propulsion. When the vehicle 1 reaches a predetermined speed, the friction C is closed, i.e., actuated, to connect the two connecting elements C11, C12, rotationally drive the crankshaft 11, and start the heat engine MT. In a possible operating mode, when the clutch C is closed, the electromechanical machine E can be advantageously accelerated by the control unit to compensate for the deceleration of the rotor R due to the increased load.

[0047] Referring to the embodiments schematically shown in FIGS. 4 and 5, during the acceleration phase of the vehicle 1, the electromechanical machine E can be turned on in "motor" mode to increase the thrust, or it can be left off, contributing no propulsion force, and the propulsion force is provided only by the heat engine MT. In the embodiment of FIG. 6, turning on the electromechanical machine E as a "motor" is instead used to complement the acceleration phase, as described above.

[0048] Continuing to refer to the embodiments schematically shown in FIGS. 4 and 5, the battery assembly B can be recharged by turning on the electromechanical machine E in "generator" mode during the constant-speed driving phase or the braking phase of the vehicle. In either case, it is possible to leave the electromechanical machine E off during one or both of these phases.

[0049] In the embodiment shown in FIG. 6, the common rotation axis 101 defined by the motor assembly 10 is oriented to be substantially parallel to the longitudinal axis Y. The arrangement shown in Figure 6 has proven to be particularly advantageous, especially with regard to rolling motion, as far as the stability of the vehicle is concerned. In fact, the plane in which the axis of the heat engine MT, and thus the axis of the rotor R of the electromechanical machine E, lies does not change during the rolling of the vehicle. In practice, in this configuration, the possible gyroscopic yawing effects, which could lead to similar effects caused by the wheels, are avoided or at least significantly reduced.

[0050] In Figure 6, the motor assembly 10 has a configuration corresponding to the configuration schematically shown in Figure 2. However, the motor assembly 10 can also be configured as shown in the embodiments shown in Figures 3 and 4, i.e., having an output shaft 112 to which the gearbox G is connected to the power transmission unit T.

[0051] In Figure 6, the power transmission unit T comprises a power transmission shaft T1 connected (for example, by a universal joint or a constant velocity joint) to the output shaft 112 of the gearbox G, and a power transmission module (for example, a hypoid) T2 that transmits the rotational movement of the shaft T1 to the drive wheels 4.

[0052] With the above technical solution, the outlined problems and objectives can be fully achieved. In particular, arranging the components (heat engine MT, electromechanical machine E, and clutch C) along the same axis facilitates assembly, makes it easier to attach them to the vehicle frame, and reduces the final manufacturing time and cost.

Claims

1. A saddle-ride type vehicle (1) comprising a frame (2), at least one steering wheel (3) rotatably connected to the frame, a single drive wheel (4), a motor assembly (10), and a power transmission unit (T) that mechanically connects the motor assembly (10) to the drive wheel (4), wherein the motor assembly (10) comprises a heat engine (MT) including a crankshaft (11), an electromechanical machine (E) including a stator (S) and a rotor (R), a clutch (C) including a drive shaft (C1) and a driven shaft (C2), and a gearbox (G) including an input shaft (111), an output shaft (112), and a plurality of gears, wherein the plurality of gears are operable by a lever or an electronic system to vary the speed of the output shaft (112) relative to the speed of the input shaft (111), wherein the crankshaft (11), the rotor (R), the drive shaft (C1), and the driven shaft (C2) are coaxial so as to rotate around a common axis of rotation (101), wherein the frame (2) of the vehicle (1) defines a longitudinal direction (Y), and wherein the common axis of rotation (101) is parallel to the axis of rotation of the output shaft (112) of the gearbox (G) and substantially parallel to the longitudinal direction (Y). Vehicle (1).

2. The vehicle (1) according to claim 1, wherein the crankshaft (11) of the heat engine (MT) is integral with the rotor (R) of the electromechanical machine (E) and the drive shaft (C1) of the clutch (C), the input shaft (111) is connected to the driven shaft (C2) of the clutch (C), and the output shaft (112) is connected to the drive wheel (4) via the power transmission unit (T).

3. The vehicle (1) according to claim 1 or 2, wherein the electromechanical machine (E) is arranged between the heat engine (MT) and the clutch (C) such that the rotor (R) is connected to the crankshaft (11) on a first side and to the drive shaft (C1) of the clutch (C) on a second side.

4. The internal combustion engine (MT) is disposed between the electric machine (E) and the clutch (C) such that the crankshaft (11) is connected to the rotor (R) of the electric machine (E) on a first side and to the drive shaft (C1) of the clutch (C) on a second side. The vehicle (1) according to claim 1 or 2.

5. The clutch (C) is disposed between the internal combustion engine (MT) and the electric machine (E). The drive shaft (C1) of the clutch (C) is integral with the crankshaft (11) of the internal combustion engine (MT), and the driven shaft (C2) of the clutch (C) is integral with the rotor (R) of the electric machine (E). The vehicle (1) according to claim 1.

6. The input shaft (111) of the gearbox (G) is connected to the rotor (R) of the electric machine (E), and the output shaft (112) is connected to the drive wheels (4) via the power transmission unit (T). The vehicle (1) according to claim 5.

7. The drive shaft (C1) of the clutch (C) is integral with the crankshaft (11) of the internal combustion engine (MT), and the driven shaft (C2) of the clutch (C) is integral with the input shaft (111) of the gearbox (G). The output shaft (112) of the gearbox (G) is connected to the rotor (R) of the electric machine (E). The rotor (R) of the electric machine (E) is connected to the drive wheels (4) via the power transmission unit (T). The vehicle (1) according to claim 1.

8. The power transmission unit (T) includes a power transmission shaft (T1) connected to the output shaft (112) of the gearbox (G), and a power transmission module (T2) that transmits the motion of the power transmission shaft (T1) to the drive wheels (4). The vehicle (1) according to claim 1.

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