Multi-stage transmission controlled by one actuator, and straddle-type vehicle equipped with internal combustion engine

Abstract

The present invention provides a straddle-type vehicle capable of reducing gear shift shock during gear shifting operation control, without a transmission clutch and a transmission clutch interlock mechanism. In this straddle-type vehicle, a clutch mechanism for disconnecting or connecting a power transmission path composed of an internal combustion engine and a multi-stage transmission is constituted by one or more (a) centrifugal clutches, or (b) dog clutches, without including a transmission clutch for generating a half-clutch state during gear shifting operation control, and the displacement of the internal combustion engine is specified as in (1), (2), (3), or (4) below.　(1) When the internal combustion engine is a single-cylinder internal combustion engine, the displacement is smaller than or equal to 250 cc.　(2) When the internal combustion engine is a twin-cylinder internal combustion engine, the displacement is smaller than or equal to 280 cc.　(3) When the internal combustion engine is a three-cylinder internal combustion engine, the displacement is smaller than or equal to 300 cc.　(4) When the internal combustion engine is a four-cylinder internal combustion engine, the displacement is smaller than or equal to 320 cc.

Description

A straddle vehicle equipped with a multi-speed transmission controlled by a single actuator and an internal combustion engine

[0001] The present invention relates to a straddle vehicle equipped with a multi-speed transmission controlled by a single actuator and an internal combustion engine.

[0002] Known examples of straddle-type vehicles equipped with a multi-stage transmission controlled by a single actuator and an internal combustion engine include those described in Patent Documents 1, 2, and 3. The straddle-type vehicles described in Patent Documents 1, 2, and 3 employ technology to reduce gear shift shock that occurs during gear shift operation control.

[0003] JP 2014-199102 A Japanese Patent No. 6196254 A Japanese Patent No. 4849542 A

[0004] The technologies of Patent Documents 1, 2, and 3 link the shift operation and the operation of the gear-changing clutch by the operation of a single shift actuator.The technologies of Patent Documents 1, 2, and 3 aim to make a saddle-ride type vehicle more compact by eliminating one actuator from a saddle-ride type vehicle equipped with a multi-stage transmission controlled by, for example, two actuators.

[0005] There is a demand for further compactness in saddle-riding vehicles, and it is conceivable to eliminate the gear-change clutch and the gear-change clutch interlocking mechanism that interlocks the gear-change clutch from Patent Documents 1, 2, and 3. However, even if the gear-change clutch and the gear-change clutch interlocking mechanism are eliminated from saddle-riding vehicles, it is still necessary to reduce gear-change shock during gear-change operation control. In addition, even if the gear-change clutch and the gear-change clutch interlocking mechanism are eliminated from saddle-riding vehicles, it is still necessary to idle the internal combustion engine when the saddle-riding vehicle is stopped.

[0006] An object of the present disclosure is to provide a saddle-ride type vehicle that simultaneously has the following features: - The saddle-ride type vehicle is equipped with a multi-speed transmission controlled by a single actuator and an internal combustion engine. - The saddle-ride type vehicle is more compact than when a gear-change clutch and a gear-change clutch interlocking mechanism are provided. - The saddle-ride type vehicle can reduce gear-change shock during gear-change operation control without providing a gear-change clutch and a gear-change clutch interlocking mechanism. - The saddle-ride type vehicle can idle the internal combustion engine when the saddle-ride type vehicle is stopped without providing a gear-change clutch and a gear-change clutch interlocking mechanism.

[0007] The gear shift shock of a saddle-ride type vehicle occurs (as acceleration and jerk) in the process where fluctuations in rotational speed and torque resulting from the difference in gear ratio before and after a gear shift in a multi-stage transmission are absorbed by speed fluctuations in the internal combustion engine, which has inertia, and speed fluctuations in the vehicle itself. The gear shift shock of a saddle-ride type vehicle is ultimately transmitted to the rider of the saddle-ride type vehicle as the behavior of the saddle-ride type vehicle.

[0008] More specifically, the technologies of Patent Documents 1, 2, and 3 reduce shift shock that occurs during shift operation control by combining one or more of the following two devices: - A control device executes control to generate a half-clutch state with one actuator so that the capacity of the shift clutch is increased gradually or in stages when the shift clutch is engaged; - A control device controls one or more of the ignition timing, fuel injection amount, and air amount so as to reduce or increase the torque of the internal combustion engine that is transmitted when the shift clutch is engaged.

[0009] Compared to automobiles, straddle-type vehicles have limited space for mounting parts, so it is sometimes desirable to reduce the number of large parts, such as actuators. The technologies of Patent Documents 1, 2, and 3 link the shift operation and the operation of a gear-change clutch with the operation of a single shift actuator. The technologies of Patent Documents 1, 2, and 3 eliminate one gear-change clutch actuator in a multi-speed transmission controlled by two actuators, one shift actuator and one gear-change clutch actuator. The technologies of Patent Documents 1, 2, and 3 aim to make the straddle-type vehicle more compact by eliminating one actuator in a straddle-type vehicle equipped with a multi-speed transmission controlled by two actuators.

[0010] To further reduce the size of saddle-riding vehicles, it is conceivable to eliminate the gear-change clutch and the gear-change clutch interlocking mechanism that interlocks the gear-change clutch from Patent Documents 1, 2, and 3. However, even if the gear-change clutch and the gear-change clutch interlocking mechanism are eliminated, saddle-riding vehicles are still required to reduce gear-change shock during gear-change operation control. In addition, even if the gear-change clutch and the gear-change clutch interlocking mechanism are eliminated, saddle-riding vehicles are still required to idle the internal combustion engine when the saddle-riding vehicle is stopped.

[0011] [Allowable Fluctuation Upper Limit Level] Shift shock in a saddle-riding type vehicle is ultimately transmitted to the rider of the saddle-riding type vehicle as a result of the vehicle's behavior. Therefore, the inventors actually evaluated the magnitude of shift shock that is tolerable in a saddle-riding type vehicle by generating shocks of various magnitudes with a test rider riding the saddle-riding type vehicle and having the test rider evaluate the shocks. As a result, an allowable fluctuation upper limit level was obtained as the upper limit of shift shock that is tolerable in a saddle-riding type vehicle. The allowable fluctuation upper limit level corresponds to the strength of the shift shock itself, and is a value that can be evaluated independently of the engine displacement of the saddle-riding type vehicle.

[0012] Next, the inventors investigated suppression of torque fluctuations that cause gear shift shock from two perspectives: - Output control of the internal combustion engine before, during, and after a gear shift - Damping in the transmission process The output control of the internal combustion engine can be adjusted as desired depending on the control mode. However, the amount of output control of the internal combustion engine is subject to constraints depending on the type of gear shift mechanism and the gear shift operation, such as due to dog separation. Therefore, the inventors first focused on the transmission process of torque fluctuations.

[0013] [Maximum Clutch Capacity of the Clutch] When a clutch that maintains an engaged state without causing a half-clutch state during a gear shift operation experiences a large instantaneous torque fluctuation, it absorbs and attenuates part of the fluctuation even when in the engaged state. The amount of this attenuation depends on the maximum clutch capacity, which is a characteristic of the clutch. In other words, the magnitude of the instantaneous torque fluctuation transmitted through the clutch is affected by the maximum clutch capacity of the clutch. The maximum clutch capacity indicates the maximum amount of torque that the clutch can transmit in the engaged state. The maximum clutch capacity of a clutch used in a saddle-ride type vehicle is determined according to the maximum output torque of the internal combustion engine mounted on the saddle-ride type vehicle. A maximum clutch capacity that allows for a certain margin above the maximum output torque is adopted so that the maximum output torque of the internal combustion engine can be transmitted. Furthermore, the larger the displacement of the internal combustion engine, the greater the maximum output torque of the internal combustion engine. Therefore, the larger the displacement of the internal combustion engine mounted on a saddle-ride type vehicle, the greater the maximum clutch capacity of the clutch.

[0014] [Number of Cylinders and Maximum Clutch Capacity of the Clutch] Furthermore, the fewer the number of cylinders in an internal combustion engine, the greater the margin expected for maximum clutch capacity. The greater the number of cylinders, the greater the number of combustions per 720 degrees of crank rotation, resulting in smaller torque fluctuations in the internal combustion engine. Conversely, the fewer the number of cylinders, the greater the torque fluctuations in the internal combustion engine. The fewer the number of cylinders in an internal combustion engine, the greater the margin expected for maximum clutch capacity of the clutch because torque including greater torque fluctuations is transmitted. In other words, the maximum clutch capacity of the clutch becomes larger.

[0015] [Reduction Ratio of Power Transmission Device] The rotational speed output from the internal combustion engine is reduced as it is transmitted through the power transmission path before reaching the drive wheels. Regarding the relationship between the displacement of the internal combustion engine mounted on a saddle-ride type vehicle and the total reduction ratio of the power transmission path from the crankshaft to the rear wheel axle, the total reduction ratio decreases as the displacement increases. In other words, the larger the displacement of the internal combustion engine, the smaller the reduction amount from the rotational speed of the internal combustion engine to the rotational speed of the rear wheels. However, the total reduction ratio does not decrease in inverse proportion to the displacement of the mounted internal combustion engine. The larger the displacement of the internal combustion engine, the smaller the decrease in the total reduction ratio with respect to the increase in displacement. In other words, the larger the displacement of the internal combustion engine, the more gradually the decrease in the total reduction ratio with respect to the increase in displacement. This is due to a trade-off between realizing a higher maximum speed as the displacement increases and achieving high acceleration by supplying greater torque to the drive wheels, for example, even at low rotation speeds, as the output power increases. [Displacement and Torque Fluctuation Characteristics] Based on the above study results, it is possible to obtain the characteristics of the displacement and potential torque fluctuation of an internal combustion engine for each number of cylinders of the internal combustion engine in a saddle-riding vehicle. Torque fluctuation can be obtained from a model of the maximum clutch capacity of the clutch, which depends on the displacement and number of cylinders of the internal combustion engine, and the total reduction ratio, which depends on the displacement of the internal combustion engine. [Relationship with the Allowable Fluctuation Upper Limit Level] Furthermore, for each number of cylinders of the internal combustion engine in a saddle-riding vehicle, an upper limit displacement can be obtained such that the obtained torque fluctuation falls below the allowable fluctuation upper limit level in the above-mentioned actual evaluation. If the displacement of the internal combustion engine is equal to or less than the upper limit displacement corresponding to the number of cylinders, the torque fluctuation falls below the allowable fluctuation upper limit level. As described above, a saddle-riding vehicle can further reduce gear shift shock by controlling the output of the internal combustion engine before, during, and after a gear shift. Here, setting an upper limit displacement for each number of cylinders imposes an upper limit on gear shift shock, thereby expanding the output control range of the internal combustion engine compared to, for example, an internal combustion engine with a larger displacement than the upper limit. In other words, even if the output control of the internal combustion engine is kept to a minimum, the shift shock is below the upper limit of the allowable shift shock, and the stronger the output control of the internal combustion engine, the more the torque fluctuation can be suppressed.

[0016] In the saddle-ride type vehicle of the present disclosure, in addition to being able to expand the output control range of the internal combustion engine, the clutch mechanism has the function of disconnecting the power transmission path when the saddle-ride type vehicle is stopped, so that the gear-shift clutch and the drive mechanism for the gear-shift clutch can be eliminated from the clutch mechanism.

[0017] As a result of the above, the following can be simultaneously achieved in a saddle-ride type vehicle: - A multi-speed transmission and an internal combustion engine controlled by a single actuator can be installed. - The saddle-ride type vehicle can be made more compact than when a gear-change clutch and a gear-change clutch interlocking mechanism are provided. - Gear-change shock during gear-change operation control can be reduced without providing a gear-change clutch and a gear-change clutch interlocking mechanism. - The internal combustion engine can be allowed to idle when the saddle-ride type vehicle is stopped without providing a gear-change clutch and a gear-change clutch interlocking mechanism.

[0018] In order to solve the above problems, according to an aspect of the present disclosure, a saddle-type vehicle has the following configuration.

[0019] [One aspect (1) of the present disclosure] A saddle-ride type vehicle equipped with a multi-speed transmission controlled by one actuator and an internal combustion engine, comprising: a multi-speed transmission having one shift actuator that controls a gear shift operation; an internal combustion engine that outputs power to the multi-speed transmission; and a control unit that controls the output of the internal combustion engine so as to reduce gear shift shock during gear shift operation control of the multi-speed transmission, wherein the saddle-ride type vehicle is characterized in that: a clutch mechanism that disconnects or connects a power transmission path formed by the internal combustion engine and the multi-speed transmission does not include a gear shift clutch that generates a half-clutch state during gear shift operation control, and is configured as one or more of the following (a) or (b); and the displacement of the internal combustion engine is configured to be smaller than or equal to an upper limit level defined in the following (1), (2), (3) or (4) depending on the number of cylinders of the internal combustion engine. (a) A centrifugal clutch that connects or disconnects the power transmission path depending on the rotational speed of the internal combustion engine without generating the half-clutch state during gear shifting operation control and without relying on external inputs other than the power of the internal combustion engine. (b) A dog clutch that disconnects the power transmission path when the shift actuator shifts the multi-stage transmission to neutral without generating the half-clutch state during gear shifting operation control. (1) If the internal combustion engine is a four-stroke single-cylinder internal combustion engine, it is smaller than or equal to 250 cc. (2) If the internal combustion engine is a four-stroke two-cylinder internal combustion engine, it is smaller than or equal to 280 cc. (3) If the internal combustion engine is a four-stroke three-cylinder internal combustion engine, it is smaller than or equal to 300 cc. (4) If the internal combustion engine is a four-stroke four-cylinder internal combustion engine, it is smaller than or equal to 320 cc.

[0020] [Action / Function] In the saddle-ride type vehicle disclosed herein, the clutch mechanism that connects or disconnects the power transmission path does not include a gear-shifting clutch, but is composed of one or more of (a) a centrifugal clutch or (b) a dog clutch. (a) A centrifugal clutch or (b) A dog clutch does not create a half-clutch state during a gear shift operation. Gear shift shock in a saddle-ride type vehicle occurs in the process of absorbing fluctuations in rotational speed and torque caused by the difference in gear ratio before and after a gear shift operation in a multi-speed transmission using speed fluctuations in the internal combustion engine, which has inertia, and speed fluctuations in the vehicle. Gear shift shock in a saddle-ride type vehicle is ultimately transmitted to the rider of the saddle-ride type vehicle as a result of the behavior of the saddle-ride type vehicle.

[0021] [Tolerable Fluctuation Upper Limit Level] The magnitude of the shift shock that can be tolerated in a saddle-riding type vehicle is actually evaluated by generating shocks of various magnitudes with a test rider riding in the saddle-riding type vehicle and having the test rider evaluate the shocks. As a result, the tolerable fluctuation upper limit level is obtained as the upper limit of the shift shock that can be tolerated in a saddle-riding type vehicle. The tolerable fluctuation upper limit level corresponds to the strength of the shift shock itself and can be obtained independently of the engine displacement of the saddle-riding type vehicle being ridden.

[0022] [Mechanism of gear shift shock] Torque fluctuations that cause gear shift shock are transmitted from the internal combustion engine to the drive wheels and vehicle body via the clutch, multi-speed transmission, chain, and hub. Suppressing torque fluctuations that cause gear shift shock can be approached from two perspectives: - Controlling the output of the internal combustion engine before, during, and after a gear shift - Damping the torque fluctuation transmission process The output control of an internal combustion engine can be adjusted as desired depending on the control format. However, it is not easy to change the output rotational speed of the internal combustion engine in the short time it takes to perform a gear shift. Therefore, attention can be focused on the torque fluctuation transmission process.

[0023] [Maximum Clutch Capacity of the Clutch] The clutch in the present disclosure does not enter a half-clutch state during a gear shift operation and maintains an engaged state. However, when the clutch experiences a momentary large torque fluctuation, it absorbs and attenuates a portion of the fluctuation even when in an engaged state. The amount of this attenuation depends on the maximum clutch capacity, which is a characteristic of the clutch. In other words, the magnitude of the momentary torque fluctuation transmitted through the clutch is affected by the maximum clutch capacity of the clutch. The maximum clutch capacity indicates the maximum amount of torque that the clutch can transmit when in an engaged state. The maximum clutch capacity of the clutch used in a saddle-ride type vehicle is determined according to the maximum output torque of the internal combustion engine mounted on the saddle-ride type vehicle. A maximum clutch capacity is adopted that allows for a certain margin above the maximum output torque so that the maximum output torque of the internal combustion engine can be transmitted. Furthermore, the larger the displacement of the internal combustion engine, the greater the maximum output torque of the internal combustion engine. Therefore, the larger the displacement of the internal combustion engine, the greater the maximum clutch capacity of the clutch.

[0024] [Number of Cylinders and Maximum Clutch Capacity of the Clutch] Furthermore, the fewer the number of cylinders in an internal combustion engine, the greater the margin expected for maximum clutch capacity. The greater the number of cylinders, the greater the number of combustions per 720 degrees of crank rotation, resulting in smaller torque fluctuations in the internal combustion engine. Conversely, the fewer the number of cylinders, the greater the torque fluctuations in the internal combustion engine. The fewer the number of cylinders in an internal combustion engine, the greater the margin expected for maximum clutch capacity of the clutch because torque including greater torque fluctuations is transmitted. In other words, the maximum clutch capacity of the clutch becomes larger.

[0025] [Reduction Ratio of the Power Transmission Device] The rotational speed output from the internal combustion engine is reduced as it is transmitted through the power transmission device before reaching the rear wheels. In a saddle-ride vehicle, the larger the displacement of the internal combustion engine and the smaller the total reduction ratio from the crankshaft to the rear wheel axle become. In other words, the larger the displacement of the internal combustion engine, the smaller the reduction amount from the rotational speed of the internal combustion engine to the rotational speed of the rear wheels. However, the total reduction ratio does not decrease in inverse proportion to the displacement of the internal combustion engine. The larger the displacement of the internal combustion engine, the smaller the decrease in the total reduction ratio with respect to the increase in displacement. In other words, the larger the displacement of the internal combustion engine, the more gradually the decrease in the total reduction ratio with respect to the increase in displacement. This is due to a trade-off between realizing a higher maximum speed as the displacement increases and the output power that can be output from the internal combustion engine, and achieving high acceleration by supplying greater torque to the drive wheels, for example, even at low rotation speeds, as the output power increases.

[0026] [Displacement and Torque Fluctuation Characteristics] From the above operation, it is possible to obtain the displacement and torque fluctuation characteristics of an internal combustion engine for each number of cylinders of the internal combustion engine in a saddle-riding vehicle. Torque fluctuation can be obtained from a model of the maximum clutch capacity of the clutch, which depends on the displacement and number of cylinders of the internal combustion engine, and a model of the total reduction ratio, which depends on the displacement of the internal combustion engine. [Relationship with the Allowable Fluctuation Upper Limit Level] Furthermore, for each number of cylinders of the internal combustion engine in a saddle-riding vehicle, an upper limit displacement can be obtained such that the obtained torque fluctuation falls below the allowable fluctuation upper limit level in the above-mentioned actual evaluation. If the displacement of the internal combustion engine is equal to or less than the upper limit displacement corresponding to the number of cylinders, the torque fluctuation falls below the allowable fluctuation upper limit level. As described above, a saddle-riding vehicle can further reduce gear shift shock by controlling the output of the internal combustion engine before, during, and after a gear shift. Here, setting an upper limit displacement for each number of cylinders imposes an upper limit on gear shift shock, thereby expanding the output control range of the internal combustion engine compared to, for example, an internal combustion engine with a larger displacement than the upper limit. In other words, even when the output control of the internal combustion engine is at a minimum, the torque fluctuation is below the magnitude of the tolerable shift shock, and the stronger the output control of the internal combustion engine is, the more the torque fluctuation can be suppressed.

[0027] In the saddle-ride type vehicle of the present disclosure, in addition to being able to expand the output control range of the internal combustion engine, the clutch mechanism has the function of disconnecting the power transmission path when the saddle-ride type vehicle is stopped, so that the gear-shift clutch and the drive mechanism for the gear-shift clutch can be eliminated from the clutch mechanism.

[0028] In this way, the saddle-ride type vehicle of the present disclosure limits the displacement according to the number of cylinders of the internal combustion engine so that the gear shift shock is within the allowable upper limit for the saddle-ride type vehicle, without half-clutch control of the gear shift clutch to reduce the capacity when the clutch is engaged or without controlling the output of the internal combustion engine. Furthermore, in the saddle-ride type vehicle of the present disclosure, the clutch mechanism has the function of disconnecting the power transmission path when the saddle-ride type vehicle is stopped. Furthermore, in the saddle-ride type vehicle of the present disclosure, the gear shift clutch and the drive mechanism for the gear shift clutch are eliminated from the clutch mechanism.

[0029] [Effects] As described above, the saddle-riding type vehicle of the present disclosure simultaneously achieves the following effects: - A multi-speed transmission and an internal combustion engine controlled by a single actuator can be mounted. - The saddle-riding type vehicle can be made more compact than when a gear-change clutch and a gear-change clutch interlocking mechanism are provided. - Gear-change shock during gear-change operation control can be reduced without providing a gear-change clutch and a gear-change clutch interlocking mechanism. - The internal combustion engine can be allowed to idle when the saddle-riding type vehicle is stopped without providing a gear-change clutch and a gear-change clutch interlocking mechanism.

[0030] [Definition of Terms] The terminology used herein is for the purpose of defining particular embodiments only and is not intended to limit the invention. As used herein, the term "and / or" includes any and all combinations of one or more of the associated listed components. As used herein, the use of the terms "including," "comprising," or "having," and variations thereof, identifies the presence of stated features, steps, operations, elements, components, and / or equivalents thereof, but may include one or more of the steps, operations, elements, components, and / or groups thereof. As used herein, the terms "attached," "connected," "coupled," and / or equivalents thereof are used broadly and encompass both direct and indirect attachments, connections, and couplings. Furthermore, "connected" and "coupled" are not limited to physical or mechanical connections or couplings, but can include direct or indirect electrical connections or couplings. Unless otherwise defined, all terms (including technical and scientific terms) used herein have the same meaning as commonly understood by one of ordinary skill in the art to which this invention belongs. Terms, such as those defined in commonly used dictionaries, should be interpreted to have a meaning consistent with the meaning in the context of the relevant technology and this disclosure, and should not be interpreted in an idealized or overly formal sense unless explicitly defined herein. It is understood that numerous techniques and processes are disclosed in the description of the present invention. Each of these has distinct advantages, and each can be used with one or more, or in some cases all, of the other disclosed techniques. Thus, for the sake of clarity, this description will refrain from unnecessarily repeating every possible combination of individual steps. Nevertheless, the specification and claims should be read with the understanding that all such combinations are within the scope of the present invention and claims. A novel straddle-type vehicle is described herein. In the following description, for purposes of explanation, numerous specific details are set forth to provide a thorough understanding of the present invention.However, it will be apparent to one skilled in the art that the present invention may be practiced without these specific details. The present disclosure is to be considered as an example of the present invention and is not intended to limit the invention to the specific embodiments illustrated by the following drawings or description.

[0031] A straddle-type vehicle is a vehicle in which the rider sits astride a saddle. A straddle-type vehicle is configured to turn with changes in the rider's posture. Since a straddle-type vehicle is required to be light and agile, responsiveness of the vehicle's movement to a starting operation is important. For this reason, a compact body is required for a straddle-type vehicle. A straddle-type vehicle is, for example, a lean vehicle configured to turn in a posture leaned toward the center of a curve. A straddle-type vehicle configured to be able to turn in a lean posture counters the centrifugal force acting on the vehicle by leaning when turning. An example of a straddle-type vehicle is an off-road motorcycle. There are no particular limitations on the type of straddle-type vehicle, and it may be, for example, an on-road vehicle, a scooter, a moped, or a three-wheeled motor vehicle.

[0032] [Gear Shift Shock] Gear shift shock is a phenomenon that is particularly noticeable in saddle-type vehicles, which are lighter than automobiles, and is an impact phenomenon in which the vehicle shakes back and forth when shifting gears.

[0033] Clutch engagement capacity: Clutch engagement capacity is the maximum torque that the clutch can transmit, and is the maximum clutch capacity.

[0034] [Half-clutch state] The half-clutch state is an intermediate clutch engagement state between the engaged state and the disengaged state, in which the clutch engagement capacity is gradually or stepwise increased. The half-clutch state is a state that is neither engaged nor disengaged.

[0035] [Shift Clutch] The shift clutch is a clutch that generates a half-clutch state during shift operation control, and is a clutch that reduces shift shock that occurs during shift operation control.

[0036] In the present disclosure, the control unit that controls the output of the shift actuator and the internal combustion engine is configured as a single control device that functions as a shift control device and an internal combustion engine control device. However, the physical configuration of the control unit is not particularly limited. For example, the shift control device and the internal combustion engine control device in the control unit may be configured as separate entities.

[0037] The clutch mechanism of the saddle-riding type vehicle in one aspect of the present disclosure does not include a shift clutch that creates a half-clutch state during gear shift control. However, the clutch mechanism of the saddle-riding type vehicle in one aspect of the present disclosure is not particularly limited. For example, the clutch mechanism that connects or disconnects a power transmission path formed by an internal combustion engine and a multi-speed transmission may not include a shift clutch that creates a half-clutch state during gear shift control, and may be configured as one or more of (a) or (b) above so as to idle the internal combustion engine when the saddle-riding type vehicle is stopped.

[0038] In one aspect of the present disclosure, the saddle-riding type vehicle is configured so that the displacement of the internal combustion engine is smaller than or equal to the upper limit level defined in (1), (2), (3), or (4) above. However, the saddle-riding type vehicle in one aspect of the present disclosure is not particularly limited. For example, the saddle-riding type vehicle may be configured so that the displacement of the internal combustion engine is smaller than or equal to the upper limit level defined in (1), (2), (3), or (4) above depending on the number of cylinders of the internal combustion engine so that the shift shock is at the upper limit allowable for the saddle-riding type vehicle without control to put the clutch into a half-clutch state or control the output of the internal combustion engine.

[0039] According to the saddle-riding type vehicle of the present disclosure, it is possible to provide a saddle-riding type vehicle that simultaneously has the following features. The saddle-riding type vehicle is equipped with a multi-speed transmission controlled by a single actuator and an internal combustion engine. The saddle-riding type vehicle is more compact than a vehicle equipped with a gear-change clutch and a gear-change clutch interlocking mechanism. The saddle-riding type vehicle can reduce gear-change shock during gear-change operation control without being equipped with a gear-change clutch and a gear-change clutch interlocking mechanism. The saddle-riding type vehicle can idle the internal combustion engine when the saddle-riding type vehicle is stopped without being equipped with a gear-change clutch and a gear-change clutch interlocking mechanism.

[0040] The present disclosure relates to a saddle-type vehicle, a vehicle body, a vehicle seat, a vehicle seating position, a vehicle seat ...

[0041] Hereinafter, embodiments of the present disclosure will be described with reference to the drawings.

[0042] [First Aspect] Fig. 1 is a diagram illustrating a saddle-ride type vehicle according to one aspect of the present disclosure. Part (a) of Fig. 1 shows a schematic configuration of the entire saddle-ride type vehicle. Part (b) of Fig. 1 is a block diagram illustrating the configuration of the periphery of a clutch mechanism of a saddle-ride type vehicle according to this aspect. Part (c) of Fig. 1 is a block diagram illustrating the configuration of the periphery of a clutch mechanism in a comparative example. Parts (d) to (g) of Fig. 1 are diagrams illustrating the characteristics of the displacement and gear shift shock of an internal combustion engine that can be employed in the saddle-ride type vehicle according to this aspect.

[0043] 1 includes a multi-speed transmission 3, an internal combustion engine 2, and a control unit 10. The saddle-riding vehicle 1 has a power transmission path P. The power transmission path P includes the internal combustion engine 2 and the multi-speed transmission 3. The saddle-riding vehicle 1 also includes drive wheels 4.

[0044] The internal combustion engine 2 outputs power to the multi-speed transmission 3. The internal combustion engine 2 is a four-stroke type. The power output from the internal combustion engine 2 is transmitted to drive wheels 4 via the multi-speed transmission 3. The power transmitted by the multi-speed transmission 3 is output from the multi-speed transmission 3 via a drive axle 32 provided in the multi-speed transmission 3. The saddle-ride type vehicle 1 travels by the power transmitted to the drive wheels 4. The control unit 10 controls the shift actuator 31 and the internal combustion engine 2. The control unit 10 has a shift control device 10b and an internal combustion engine control device 10a. The shift control device 10b controls the shift actuator 31. The internal combustion engine control device 10a controls the internal combustion engine 2. The internal combustion engine control device 10a controls the output of the internal combustion engine 2 by controlling, for example, one or more of the ignition timing, the fuel injection amount, and the air amount in the internal combustion engine 2. For example, the internal combustion engine control device 10a controls the output of the internal combustion engine 2 when the shift control device 10b causes the shift actuator 31 to perform a shift operation. However, the operation of the internal combustion engine control device 10a is not particularly limited, and for example, it does not have to control the output of the internal combustion engine 2 during a shift operation. The shift control device 10b and the internal combustion engine control device 10a are provided within the control unit 10.

[0045] The straddle-type vehicle 1 has a clutch mechanism C in a power transmission path P. The clutch mechanism C connects or disconnects the power transmission path P, which includes an internal combustion engine (ICE) 2 and a multi-stage transmission 3. However, the clutch mechanism C does not include a gear-shifting clutch that generates a half-clutch state during gear-shifting operation control. The clutch mechanism C is composed of one or more of (a) a centrifugal clutch mechanism C1 or (b) a dog clutch mechanism C2. (a) The centrifugal clutch mechanism C1 connects or disconnects the power transmission path P depending on the rotational speed of the internal combustion engine 2, without generating a half-clutch state during gear-shifting operation control, and without relying on external inputs other than the power of the internal combustion engine 2. The centrifugal clutch mechanism C1 is provided separately from the multi-stage transmission 3. The centrifugal clutch mechanism C1 is arranged in series with the multi-stage transmission 3 in the power transmission path P. The centrifugal clutch mechanism C1 disconnects the power transmission path P, for example, when the rotational speed of the internal combustion engine 2 falls below a predetermined idle speed. The centrifugal clutch mechanism C1 connects the power transmission path P, for example, when the rotational speed of the internal combustion engine 2 exceeds the idle speed. The centrifugal clutch mechanism C1 may have a structure that includes a weight that rotates in accordance with the rotation of the internal combustion engine 2 and a cam that acts on the weight, and connects the path by the action of the weight and the cam that move outward due to centrifugal force when the weight rotates. (b) The dog clutch mechanism C2 disconnects the power transmission path P when the multi-speed transmission 3 is shifted to neutral by the shift actuator 31, without generating a half-clutch state during gear shift operation control. The dog clutch mechanism C2 is, for example, built into the multi-speed transmission 3 provided in the power transmission path P. The multi-speed transmission 3 is, for example, a dog-type transmission, and shifts gears by engaging and disengaging built-in dogs with gears corresponding to the gears. The dog clutch mechanism C2 is configured, for example, by a dog built into the multi-speed transmission 3 and a gear that is provided so as to be able to engage with the dog. When the multi-speed transmission 3 shifts to neutral, the dog clutch mechanism C2 separates the dog, thereby cutting the power transmission path P. When the multi-speed transmission 3 shifts to a state other than neutral, the dog clutch mechanism C2 connects the power transmission path P by engaging the dog with the gear.

[0046] In contrast to the saddle-riding type vehicle 1 of the present embodiment, in a comparative example shown in part (c) of FIG. 1 , the clutch mechanism Y includes a shift clutch Y3 that generates a half-clutch state during gear shift control. Specifically, the clutch mechanism Y of the comparative example includes a centrifugal clutch Y1, a dog clutch Y2, and a shift clutch Y3. The shift clutch Y3 is provided independently of the centrifugal clutch Y1 and the dog clutch Y2 and generates a half-clutch state during gear shift control. When the shift clutch Y3 of the comparative example is used, it is necessary to provide a dedicated actuator for the shift clutch Y3 or a shift clutch interlocking mechanism. In the above comparative example, the shift clutch Y3 is provided independently of the centrifugal clutch Y1 and the dog clutch Y2. However, the comparative example for the saddle-riding type vehicle 1 of the present embodiment also includes, for example, a shift clutch integrated with a centrifugal clutch. In a gear-shifting clutch combined with a centrifugal clutch, for example, the clutch plates that transmit power are shared between the functions of the gear-shifting clutch and the centrifugal clutch. More specifically, in a centrifugal clutch, for example, a pressing member that presses the clutch plates together by the action of a weight is configured to release the pressing member when shifting gears by an external input other than the power of the internal combustion engine. Even when such a gear-shifting clutch combined with a centrifugal clutch is used, it is necessary to provide an actuator that drives the release during gear shifting, or a gear-shifting clutch interlocking mechanism.

[0047] The internal combustion engine 2 mounted on the saddle-riding vehicle 1 of this embodiment may be a single-cylinder, two-cylinder, three-cylinder, or four-cylinder engine. Furthermore, engines with various displacements may be employed as the internal combustion engine 2. However, the displacement of the internal combustion engine 2 according to this embodiment is limited depending on the number of cylinders of the internal combustion engine 2. More specifically, the saddle-riding vehicle 1 is configured so that the displacement of the internal combustion engine 2 is smaller than or equal to the upper limit level defined in (1), (2), (3), or (4) below depending on the number of cylinders of the internal combustion engine 2. (1) If the internal combustion engine 2 is a four-stroke single-cylinder internal combustion engine, it is smaller than or equal to 250 cc. (2) If the internal combustion engine 2 is a four-stroke two-cylinder internal combustion engine, it is smaller than or equal to 280 cc. (3) If the internal combustion engine 2 is a four-stroke three-cylinder internal combustion engine, it is smaller than or equal to 300 cc. (4) If the internal combustion engine 2 is a four-stroke, four-cylinder internal combustion engine, it is smaller than or equal to 320 cc.

[0048] The saddle-riding vehicle 1 of this embodiment described above is equipped with a multi-speed transmission 3 controlled by a single shift actuator 31 and an internal combustion engine 2. With the saddle-riding vehicle 1 of this embodiment, the internal combustion engine 2 can be idled when the saddle-riding vehicle 1 is stopped, without providing a gear-change clutch Y3 or a gear-change clutch combined with a centrifugal clutch, as in the comparative example shown in part (c) of FIG. 1 , or a gear-change clutch interlocking mechanism. Furthermore, with the saddle-riding vehicle 1 of this embodiment, the saddle-riding vehicle 1 can be made more compact than when a gear-change clutch Y3 and a gear-change clutch interlocking mechanism are provided, as in the comparative example shown in part (c) of FIG. 1 . Furthermore, gear-change shock during gear-change operation control can be reduced without providing a gear-change clutch and a gear-change clutch interlocking mechanism.

[0049] [Reduction of Shift Shock During Shift Operation Control] Here, reduction of shift shock during shift operation control in the saddle riding type vehicle 1 of this embodiment will be described.

[0050] The gear shift shock of the saddle riding type vehicle 1 occurs as acceleration and jerk in the process in which fluctuations in rotation speed and torque caused by the difference in gear ratio before and after a gear shift operation in the multi-stage transmission 3 are absorbed by speed fluctuations of the internal combustion engine 2, which has inertia, and speed fluctuations of the saddle riding type vehicle 1. The gear shift shock of the saddle riding type vehicle 1 is ultimately transmitted to the rider of the saddle riding type vehicle 1 as the behavior of the saddle riding type vehicle 1.

[0051] [Upper limit level of allowable fluctuation] First, the magnitude of the shift shock that can be tolerated in the saddle-riding type vehicle 1 was actually evaluated. Fig. 2 is a table showing evaluation data on the tolerance of shock. Part (a) of Fig. 2 is a table showing the conditions for the evaluation. Part (b) of Fig. 2 is a table showing the results of the evaluation. Under the conditions shown in part (a) of Fig. 2, shocks of various magnitudes were generated while a test rider was riding on the saddle-riding type vehicle 1, and the test rider was asked to evaluate the tolerance of each shock.

[0052] As a result, the evaluation results shown in part (b) of FIG. 2 were obtained. The table in part (b) of FIG. 2 shows the magnitude of the shock as a driving force equivalent of the torque fluctuation. Furthermore, since the magnitude of the shock is sometimes expressed as jerk (the rate of change of acceleration over time), the table in part (b) of FIG. 2 also shows the magnitude of the jerk when the gearshift time is 0.1 s, 0.2 s, and 0.3 s. As a result of the evaluation, the driving force equivalent of the torque fluctuation of 1110 N was determined to be the upper limit of the magnitude of the gearshift shock that can be tolerated in the saddle-riding type vehicle 1. For example, 770 N, which is smaller than the upper limit, was evaluated as acceptable, while 1220 N, which is larger than the upper limit, was evaluated as unacceptable. The upper limit of the magnitude of the gearshift shock that can be tolerated in the saddle-riding type vehicle 1, 1110 N, is set as the allowable fluctuation upper limit level. The allowable fluctuation upper limit level corresponds to the strength of the shock itself, and the allowable fluctuation upper limit level itself does not depend on the displacement of the internal combustion engine 2 and can be evaluated independently of the displacement.

[0053] The reliability of the upper limit of tolerable fluctuations obtained from this actual evaluation can be confirmed, for example, from the research in the following paper: "Standards for passenger comfort in automated vehicles: Acceleration and jerk" (https: / / www.sciencedirect.com / science / article / pii / S0003687022002046?via%3Dihub) This paper considers the following: (1) Discomfort varies depending on the direction. Overall, forward movement is the most comfortable, followed by backward movement, and lateral movement is the most uncomfortable. (2) With regard to jerk and comfort, it shows that high jerk with a short pulse duration is associated with less discomfort.

[0054] It should be noted that this paper considers passenger comfort standards for self-driving vehicles, and therefore in the case of this embodiment, it should be taken into consideration that the vehicle is a saddle-type vehicle and that the subject of evaluation is the rider operating the saddle-type vehicle. The posture and body usage of a rider in a saddle-type vehicle are significantly different from those of a car passenger. A rider can absorb impacts using their knees and arms, and rides while maintaining balance with their entire body. Furthermore, the gear shift shock that is the target of reduction in this embodiment is not only the movement of the saddle-type vehicle in the forward and backward directions, but also fluctuations over a short gear shift time of 0.1 to 0.3 seconds. Therefore, in this paper, a 15 m / s ３ Although the experiment was conducted with this as the maximum value, even higher values ​​are within the expected range for the tolerance level of gear shift shock in saddle-type vehicles. Therefore, the tolerance upper limit level of fluctuation for gear shift shock obtained in this evaluation is consistent with the findings of the paper, and can be said to be appropriate as a tolerance value for gear shift shock, even when considering the conditions unique to saddle-type vehicles.

[0055] Next, the transmission path of gear shift shock and the basic mechanism for reducing it will be explained.

[0056] Torque fluctuations that cause gear shift shock are transmitted from the internal combustion engine 2 to the multi-speed transmission 3, then to the drive wheels 4 via transmission mechanisms such as a chain and hub, and then to the vehicle body. Therefore, the magnitude of the gear shift shock can be converted into a driving force equivalent to the amount of torque fluctuation. Suppressing torque fluctuations that cause gear shift shock can be approached from two perspectives: Output control of the internal combustion engine 2 before, during, and after a gear shift; and Attenuation of torque fluctuations during the transmission process. For example, when upshifting, the output of the internal combustion engine 2 is reduced so as to reduce the output rotation speed of the internal combustion engine 2 in accordance with the difference in the gear ratio before and after the gear shift. The output control of the internal combustion engine 2 is adjusted as desired depending on the control mode. However, the gear shift operation is performed in a short time, for example, from 0.1 to 0.3 seconds. It is not easy to change the output rotation speed of the internal combustion engine 2 in a short time.

[0057] Next, the displacement of the internal combustion engine 2 in the saddle-ride type vehicle 1 and the magnitude of the gear shift shock will be described with regard to the torque fluctuation transmission process.

[0058] [Maximum Clutch Capacity of the Clutch] The clutch mechanism C in this embodiment does not enter a half-clutch state during a gear shift operation and maintains an engaged state. However, when the clutch mechanism C is subjected to a momentary large torque fluctuation, it absorbs and attenuates part of the fluctuation even when in an engaged state. The amount of this attenuation depends on the maximum clutch capacity, which is a characteristic of the clutch mechanism C itself. In other words, the magnitude of the momentary torque fluctuation transmitted by the clutch mechanism C is affected by the maximum clutch capacity of the clutch mechanism C. The maximum clutch capacity indicates the maximum amount of torque that the clutch mechanism C can transmit in an engaged state. The maximum clutch capacity of the clutch mechanism C employed in the saddle-riding type vehicle 1 is determined according to the maximum output torque of the internal combustion engine 2 mounted on the saddle-riding type vehicle 1. More specifically, a maximum clutch capacity is employed that allows for a certain margin of error relative to the maximum output torque so that the maximum output torque of the internal combustion engine 2 can be transmitted.

[0059] The larger the displacement of the internal combustion engine 2 mounted on the saddle-ride type vehicle 1, the larger the maximum output torque of the internal combustion engine 2. The maximum output torque of the internal combustion engine 2 is basically proportional to the displacement. Therefore, the larger the displacement of the internal combustion engine 2, the larger the maximum clutch capacity of the clutch.

[0060] [Number of Cylinders and Maximum Clutch Capacity of the Clutch] Furthermore, the fewer the number of cylinders in the internal combustion engine 2 mounted on the saddle-riding vehicle 1, the greater the expected margin in maximum clutch capacity. In other words, the greater the number of cylinders in the internal combustion engine 2 mounted on the saddle-riding vehicle 1, the smaller the expected margin. The reason for this is that the more cylinders the saddle-riding vehicle 1 has, the greater the number of combustions per 720 degrees of crank rotation, thereby reducing torque fluctuations in the internal combustion engine 2. Conversely, the fewer the number of cylinders the internal combustion engine 2 has, the greater the torque fluctuations in the internal combustion engine 2. Therefore, the fewer the number of cylinders the internal combustion engine 2 has, the greater the expected margin in maximum clutch capacity of the clutch mechanism C because it transmits torque that includes large torque fluctuations with a crank rotation period. In other words, the fewer the number of cylinders the internal combustion engine 2 has, the greater the maximum clutch capacity of the clutch mechanism C mounted on the saddle-riding vehicle 1.

[0061] [Reduction Ratio of Power Transmission Device] Furthermore, the rotational speed output from the internal combustion engine 2 is reduced while being transmitted through the power transmission path P before reaching the drive wheels 4. In the relationship between the displacement of the internal combustion engine 2 mounted on the saddle-riding vehicle 1 and the total reduction ratio of the power transmission path P from the crankshaft of the internal combustion engine 2 to the drive wheels 4, the total reduction ratio decreases as the displacement increases. In other words, the greater the displacement of the internal combustion engine 2, the smaller the amount of reduction from the rotational speed of the internal combustion engine 2 to the rotational speed of the rear wheels. However, the total reduction ratio does not decrease in inverse proportion to the displacement of the mounted internal combustion engine 2. The greater the displacement of the internal combustion engine 2, the smaller the rate at which the total reduction ratio decreases relative to the rate at which the displacement of the internal combustion engine 2 increases. In other words, the greater the displacement, the more gradually the decrease in the total reduction ratio relative to the rate at which the displacement of the internal combustion engine increases. This is because, as the displacement increases and the output power that can be output from the internal combustion engine 2 increases, a higher maximum speed can be achieved, and as the output power that can be output increases, a greater torque can be supplied to the drive wheels, for example, at low revolutions, thereby achieving high acceleration.

[0062] [Characteristics of Displacement and Torque Fluctuation] From the above-described operations, it is possible to obtain the characteristics of the displacement of the internal combustion engine 2 and the torque fluctuation that may occur for each number of cylinders of the internal combustion engine 2 in the saddle-riding vehicle 1. The torque fluctuation can be obtained from a model of the speed difference of the internal combustion engine 2 when it is assumed that the vehicle speed is the same before and after shifting to a reference gear, the inertia of the internal combustion engine 2, the maximum clutch capacity of the clutch mechanism C, which depends on the displacement and number of cylinders of the internal combustion engine 2, and the total reduction gear ratio, which depends on the displacement of the internal combustion engine 2. The torque fluctuation is obtained, for example, by multiplying the maximum clutch capacity by the total reduction gear ratio and a coefficient based on the speed difference. In other words, the torque fluctuation is determined, for example, by the product of the maximum clutch capacity by the total reduction gear ratio.

[0063] [Relationship with the Allowable Fluctuation Upper Limit Level] Then, for each number of cylinders of the internal combustion engine 2 in the saddle-riding vehicle 1, an upper limit displacement is obtained such that the acquired torque fluctuation falls below the magnitude of the allowable fluctuation upper limit level in the actual evaluation described above. Parts (d) to (g) of FIG. 1 are graphs showing the relationship between the displacement of the internal combustion engine 2 and the torque fluctuation amount as a gear shift shock. FIG. 3 is a graph showing an enlarged view of parts (d) to (g) of FIG. 1. To maintain consistency with FIG. 1, parts (a) to (c) are omitted from FIG. 3, and the graph begins with part (d). Parts (d) of FIGS. 1 and 3 show the relationship for a single-cylinder engine, part (e) shows the relationship for a two-cylinder engine, part (f) shows the relationship for a three-cylinder engine, and part (g) shows the relationship for a four-cylinder engine. The graphs also show the driving force equivalent (right-hand scale) of the gear shift shock, which is the torque fluctuation amount, on the drive axle. The graphs also show the total reduction ratio and maximum clutch capacity corresponding to the displacement. Furthermore, the graph also shows the upper limit level 1110(N) of the allowable fluctuation of the gear shift shock that is tolerable in the straddle-type vehicle 1, which was obtained from the actual shock evaluation described above.

[0064] If the displacement of the internal combustion engine 2 mounted on the saddle-riding vehicle 1 is equal to or less than the upper limit displacement corresponding to the number of cylinders, the torque fluctuation will be below the magnitude of the allowable fluctuation upper limit level. For example, as shown in part (d) of Figure 3, if the internal combustion engine 2 mounted on the saddle-riding vehicle 1 is a four-stroke, single-cylinder internal combustion engine, the torque fluctuation will be below the allowable fluctuation upper limit level of 1110 N if the displacement of the internal combustion engine 2 is 250 cc or less. Also, as shown in part (e) of Figure 3, if the internal combustion engine 2 mounted on the saddle-riding vehicle 1 is a four-stroke, two-cylinder internal combustion engine, the torque fluctuation will be below the allowable fluctuation upper limit level of 1110 N if the displacement of the internal combustion engine 2 is 280 cc or less. Also, as shown in part (f) of Figure 3, if the internal combustion engine 2 mounted on the saddle-riding vehicle 1 is a four-stroke, three-cylinder internal combustion engine, the torque fluctuation will be below the allowable fluctuation upper limit level of 1110 N if the displacement of the internal combustion engine 2 is 300 cc or less. Furthermore, as shown in part (g) of Figure 3, when a four-stroke, four-cylinder internal combustion engine is mounted as the internal combustion engine 2 in the saddle-ride type vehicle 1, if the displacement of the internal combustion engine 2 is 320 cc or less, the torque fluctuation amount falls below the allowable fluctuation upper limit level of 1110 N.

[0065] Therefore, according to the saddle-ride type vehicle 1 of this embodiment, it is possible to reduce the shift shock during the shift operation control to an acceptable level without providing a shift clutch and a shift clutch interlocking mechanism.

[0066] In the saddle-riding vehicle 1, by setting the displacement of the internal combustion engine 2 to be equal to or less than the upper limit displacement corresponding to the number of cylinders, it is possible to reduce the gear shift shock during gear shift operation control. In addition, as described above, the gear shift shock during gear shift operation control can also be reduced by controlling the output of the internal combustion engine 2. In the saddle-riding vehicle 1, by setting the displacement of the internal combustion engine 2 to be equal to or less than the upper limit displacement, it is possible to reduce the gear shift shock to an acceptable level, and therefore the range of output control of the internal combustion engine 2 can be expanded compared to, for example, an internal combustion engine whose displacement is greater than the upper limit displacement. In other words, even when the output control of the internal combustion engine 2 is minimized, the gear shift shock falls below the upper limit of the acceptable gear shift shock, and the stronger the output control, the more the torque fluctuation can be suppressed.

[0067] In the saddle-ride type vehicle 1 of this embodiment, in addition to being able to further increase the effect of output control of the internal combustion engine 2, the clutch mechanism C has the function of disconnecting the power transmission path P when the saddle-ride type vehicle 1 is stopped, so that the gear-change clutch Y3 and the drive mechanism of the gear-change clutch Y3 as shown in part (c) of Figure 1 can be eliminated from the clutch mechanism C.

[0068] In the saddle-riding vehicle 1 of this aspect, the displacement is limited in accordance with the number of cylinders of the internal combustion engine 2 so that the gear shift shock is at the upper limit that is tolerable for the saddle-riding vehicle 1, without half-clutch control of the gear shift clutch to reduce the capacity when the clutch is engaged and without output control of the internal combustion engine 2. Also, in the saddle-riding vehicle 1 of this aspect, the clutch mechanism C has the function of disconnecting the power transmission path P when the saddle-riding vehicle 1 is stopped. Also, in the saddle-riding vehicle 1 of this aspect, the gear shift clutch and the drive mechanism for the gear shift clutch are excluded from the clutch mechanism C.

[0069] As described above, the saddle-riding type vehicle 1 of this embodiment has the following advantages: - The saddle-riding type vehicle 1 is equipped with the multi-speed transmission 3 and the internal combustion engine 2, which are controlled by a single shift actuator 31. - The saddle-riding type vehicle 1 can be made more compact than when a gear-change clutch and a gear-change clutch interlocking mechanism are provided. - Gear-change shock during gear-change operation control can be reduced without providing a gear-change clutch and a gear-change clutch interlocking mechanism. - The internal combustion engine 2 can be idled when the saddle-riding type vehicle 1 is stopped without providing a gear-change clutch and a gear-change clutch interlocking mechanism.

[0070] 1: saddle-ride type vehicle 2: internal combustion engine 3: multi-speed transmission 10: control unit 31: shift actuator C: clutch mechanism P: power transmission path

Claims

1. A straddle-type vehicle equipped with a multi-speed transmission controlled by one actuator and an internal combustion engine, comprising: a multi-speed transmission having one shift actuator that controls gear shifting operations; an internal combustion engine that outputs power to the multi-speed transmission; and a control unit that controls the output of the internal combustion engine so as to reduce gear shift shock during gear shifting control of the multi-speed transmission, wherein the straddle-type vehicle is characterized in that: a clutch mechanism that disconnects or connects a power transmission path formed by the internal combustion engine and the multi-speed transmission does not include a gear shifting clutch that generates a half-clutch state during gear shifting control, and is configured as one or more of (a) or (b) below; and the displacement of the internal combustion engine is configured to be smaller than or equal to the upper limit level defined in (1), (2), (3) or (4) below, depending on the number of cylinders of the internal combustion engine. (a) A centrifugal clutch that connects or disconnects the power transmission path depending on the rotational speed of the internal combustion engine without generating the half-clutch state during gear shifting operation control and without relying on external inputs other than the power of the internal combustion engine. (b) A dog clutch that disconnects the power transmission path when the shift actuator shifts the multi-stage transmission to neutral without generating the half-clutch state during gear shifting operation control. (1) If the internal combustion engine is a four-stroke single-cylinder internal combustion engine, it is smaller than or equal to 250 cc. (2) If the internal combustion engine is a four-stroke two-cylinder internal combustion engine, it is smaller than or equal to 280 cc. (3) If the internal combustion engine is a four-stroke three-cylinder internal combustion engine, it is smaller than or equal to 300 cc. (4) If the internal combustion engine is a four-stroke four-cylinder internal combustion engine, it is smaller than or equal to 320 cc.

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