Shift control device for a vehicle

A shift control device in which a number of times that an angle change amount per a defined time period is successively equal to or less than a determined value is calculated, when a rotation angle of a shift shaft is equal to or more than a threshold value. In addition, an abutting state determination is performed that determines whether the number of times is equal to or above a threshold value, and if it is determined that there is an abutting state (namely, the shift shaft has reached an actual mechanical maximum rotation angle), processing shifts to an engagement process of a shift clutch.

RELATED APPLICATIONS

This application is related to, and claims priority from, Japanese Patent Application No. 2006-292899, filed Oct. 27, 2006, the entirety of which is hereby incorporated by reference herein and made a part of the present specification.

BACKGROUND OF THE INVENTION

1. Field of the Invention

The present invention generally relates to a shift control device that performs a clutch operation and a shift operation using a drive of an actuator, such as a motor, and a vehicle provided with such a shift control device.

2. Description of the Related Art

Shift control devices are known in which engagement and disengagement of a clutch or switching of a speed gear is performed based on interlock with rotation of a shift shaft that is caused to rotate by a drive force of a motor. For example, Japanese Publication No. 2000-27991 illustrates such a shift control device.

In addition, in Japanese Publication No. 2000-27991, a method for correcting a neutral position of the shift shaft is disclosed. More specifically, respective rotation angles when the shift shaft has rotated to a maximum rotation angle in the normal rotation direction or the reverse rotation direction are detected, and the neutral position of the shift shaft is determined to be the intermediate position between these rotation angles. Then, the neutral position is updated and recorded.

SUMMARY OF THE INVENTION

An aspect of the present invention is the realization by the present inventors that the setting method for the neutral position disclosed in Japanese Publication No. 2000-27991 has the problem that, when a number of vehicles are manufactured, there are occasions when design error of structural components, assembly error and the like can cause each vehicle to have different mechanical maximum rotation angles in the normal rotation direction and the reverse rotation direction of the shift shaft. If the maximum rotation angles in the normal rotation direction and the reverse rotation direction are different, when the neutral position is calculated based on the detected rotation angles, the calculated neutral position is different from the actual neutral position. If a neutral position that has been miscalculated in this way is used as a reference value, there are occasions when the gear change shift operation will not be accurate.

Certain preferred embodiments of the present invention have been devised in light of the above-described circumstances, and it is an object thereof to provide a shift control device that can perform gear change shift reliably even when design or assembly error (including normal manufacturing variations) exist.

A preferred embodiment involves a shift control device that includes a clutch, a speed change device having a plurality of speed gear ratios, an actuator, a shift shaft that is rotated by a driving force of the actuator, a clutch transmission mechanism that engages and disengages the clutch in response to rotation of the shift shaft, a speed change device transmission mechanism that switches the speed gear ratio in response to rotation of the shift shaft, and a control device that controls a drive of the actuator, the shift control device further includes a stopper that directly or indirectly regulates rotation of the shift shaft such that a rotation angle of the shift shaft does not exceed a defined mechanical maximum rotation angle; and a first determination device that performs an abutting state determination that determines whether the rotation angle of the shift shaft has reached the mechanical maximum rotation angle.

Another preferred embodiment is a shift control device as described above, wherein an abutting state determination is performed that determines whether the rotation angle of the shift shaft has reached the mechanical maximum rotation angle. As a result, a configuration can be adopted in which, during the clutch disengagement process performed during gear change shift, the control device waits until the abutting state determination is satisfied before initiating the clutch engagement process. Accordingly, the gear change shift can be performed once the clutch is definitely disengaged. As a result of adopting such a configuration, even if the above-described mechanical maximum rotation angle is different for different vehicles due to design error, assembly error and the like (including normal manufacturing variations) of structural members, gear change shift can be performed reliably.

According to the preferred embodiments of the invention a gear change shift can be performed reliably even when design error or assembly error exists, including normal manufacturing variations.

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

Several preferred embodiments of the present invention are described below with reference to the drawings.

First Embodiment

FIG. 1shows a motorcycle10according to a first embodiment. The motorcycle10includes a body frame11that forms a frame, and a seat16on which a rider sits. The illustrated motorcycle10is a moped-type motorcycle. However, the term “moped-type” as used here merely indicates the type of the vehicle's shape, and is not intended to either limit the maximum speed, the displacement or the like of the vehicle, or the size of the vehicle or the like. In addition, the straddle-type vehicle according to the invention is not limited to being a moped-type motorcycle. Accordingly, the invention may be applied to types of motorcycles in which a fuel tank is disposed in front of a seat, and thus may be applied to any straddle-type vehicle, such as a three-wheeled motor vehicle or an ATV. In addition, the invention is not limited to being used in straddle-type vehicles, and may be applied to other vehicles such as a two person buggy or the like.

In the following description, the directions front and rear, and left and right indicate the front and rear and the left and right directions when viewed from a rider seated on the seat16. The body frame11includes a steering head pipe12, a single main frame13that extends diagonally downwards to the rear from the steering head pipe12, a left and right pair of seat rails14that extend diagonally upward to the rear from a central section of the main frame13, and a left and right pair of rear stays15that extend diagonally upward to the rear from the main frame13from a point further to the rear side from the seat rails14. The rear stays15are connected to a rear end section of the main frame13and a central section of the seat rails14. A front wheel19is connected to the steering head pipe12via a front fork18.

An upper side and the left and right sides of the body frame11are mainly covered by a main cover21aand side covers21b. Hereinafter, the main cover21aand the side covers21bare referred to together as a body cover21.

A left and right pair of engine brackets22protrudes downwardly from a central section of the main frame13.

In addition, a rear arm25is swingably supported by a body frame rear lower section. A rear wheel26is supported by a rear end section of the rear arm25. A rear end portion of the rear arm25is coupled to the body frame11via a cushion unit, or shock absorber27.

The motorcycle10is provided with a front fender31that is positioned above and to the rear of the front wheel19, a rear fender32that is positioned above the upper side of the rear wheel26at a position diagonally upwards to the rear from the rear wheel26. In addition, the motorcycle10includes, in addition to the above-described body cover21, a front cowl33, and left and right leg shields34.

An engine unit28that drives the rear wheel26is supported by the body frame11. The engine unit28is provided with a crank case35and a cylinder43that extends forward or diagonally upward from the crank case35.

Foot rests85are disposed to the left and right sides of the engine unit28. The left and right foot rests85are supported by the crank case35via connection shafts87and attachment plates88fixed to the connection shafts87.

The structure of the engine unit28is described with reference toFIG. 2andFIG. 3, among others. The engine unit28is provided with an engine29that has a crank shaft30, a centrifugal clutch36, a shift clutch37that is engaged and disengaged during a shift operation, and a speed change device38, such as a multi-speed transmission. Note that, the type of the engine29that is used is not limited. However, in this embodiment, the engine29is a 4-stroke single cylinder engine. The engine29is not limited to an internal combustion engine, such as the gasoline engine of this embodiment. Accordingly, the engine29may be a electric motor or the like. In addition, the above-described engine may be an engine that combines a gasoline engine and an electric motor.

As shown inFIG. 3, the centrifugal clutch36is attached to a right end section of the crank shaft30. Although omitted from the figures, the centrifugal clutch36is provided with a clutch boss fixed to the crank shaft30, and a clutch housing. The centrifugal clutch36is disengaged during idling, and is engaged when the vehicle is running. More specifically, the centrifugal clutch36is disengaged when the rotation speed of the crank shaft30(the engine speed) is smaller than a defined rotation speed, and is engaged at a rotation speed equal to or above the defined rotation speed.

The shift clutch37is a wet-type multi disk clutch, and is provided with a clutch boss37aand a clutch housing37b. Note that, the type of shift clutch37used is not limited. A gear41is provided in the centrifugal clutch36, and a gear42is provided in the clutch housing37bof the shift clutch37. The gear41and the gear42are intermeshed. As a result, the clutch housing37bof the shift clutch37turns along with the centrifugal clutch36(more specifically, the clutch housing of the centrifugal clutch36).

The clutch boss37ais attached to a main shaft44, and rotates along with the main shaft44. The clutch housing37bis attached to the main shaft44such that the clutch housing37bcan rotate freely. A plurality of friction plates39aare coupled for rotation with the clutch boss37a, and a plurality of clutch plates39bare coupled for rotation with the clutch housing37b. Each one of the friction plates39ais disposed between neighboring clutch plates39b.

A pressure plate37cis disposed to the right side of the clutch boss37a. The pressure plate37cis able to slide freely in the axial direction, and is urged by a compression spring60toward the left inFIG. 3. More specifically, the pressure plate37cis urged in a direction that presses the friction plates39aand the clutch plates39btogether. When the pressure plate37cmoves toward the right against the urging force of the compression spring60, the friction plates39aand the clutch plates39bseparate from one another to permit relative rotation therebetween, and the shift clutch37is disengaged.

As shown inFIG. 2, a plurality of speed gears46extends from the outer periphery of the main shaft44. A plurality of speed gears47are attached to a drive shaft45that is disposed parallel to the main shaft44. The speed gears46on the side of the main shaft44and the speed gears47on the side of the drive shaft45are suitably meshed.

The speed gears46and the speed gears47are attached such that, apart from the gears that are selected, either one or both of the speed gears46and the speed gears47rotate idly with respect to the main shaft44or the drive shaft45. As a result, driving force is only transmitted from the main shaft44to the drive shaft45via whichever pair of the speed gears has been selected.

Selection of the speed gears is performed using a shift cam113(refer toFIG. 4). As shown inFIG. 4, the speed change device38is provided with a shift fork111athat slides the speed gears46in the axial direction of the main shaft44, and a slide rod112athat supports the shift fork111asuch that the shift fork111acan slide freely. In addition, the speed change device38is also provided with a shift fork111bthat slides the speed gears47in the axial direction of the drive shaft45, and a slide rod112bthat supports the shift fork111bsuch that the shift fork111bcan slide freely. Cam grooves113aare formed around the periphery of the shift cam113, and the shift forks111a,111bslide along the cam grooves113a.

The shift cam113turns via a ratchet mechanism115when a shift shaft70turns. Note that, the ratchet mechanism115corresponds to a speed change device transmission mechanism of the invention. The ratchet mechanism115rotates the shift cam113a defined distance (angle) each time it rotates the shift cam113, and moves the shift forks111a,111bin a regular manner. The ratchet mechanism115functions as a ratchet that shifts one speed at a time in the forward or reverse directions. A shift arm116of the ratchet mechanism115transmits the rotation of the shift shaft70, and also regulates the stroke of the shift shaft70to prevent overrun of the shift cam113. In addition, a stopper plate117of the ratchet mechanism115is provided to fix the shift cam113in a defined position.

The illustrated speed change device38is a dog clutch transmission. As shown inFIG. 5, the speed gears46include a first gear46athat is formed with an engagement protrusion46cin a shaft end surface, and a second gear46bthat is formed with an engagement groove46ein an axial end surface that faces the engagement protrusion46c. The speed change device38is provided with a plurality of the first gears46aand the second gears46b. Note that, the speed gears47(FIG. 2) have the same structure as the speed gears46, and thus are omitted from this explanation. In the illustrated arrangement, three of the engagement protrusions46care formed in each first gear46a. These engagement protrusions46care positioned evenly in the circumferential direction along the outer edge section of the axial end surface of each first gear46a. In addition, in the illustrated arrangement, six of the engagement grooves46eare formed in the second gear46b. These engagement grooves46eare also positioned evenly in the circumferential direction.

In addition, a through hole46g, into which the main shaft44and the drive shaft45are inserted, is formed in a shaft center section of each first gear46a. A plurality of grooves46dare formed in the periphery surface of the through hole46g. Note that, as shown inFIG. 2, the main shaft44is inserted into the speed gears46, and the drive shaft45is inserted into the speed gears47. The first gears46aare spline fitted to the main shaft44and the drive shaft45. Through holes46hinto which the main shaft44and the drive shaft45are inserted are also formed in the second gears46b. However, no grooves are formed in the through holes46h. Accordingly, the second gears46bare attached to the main shaft44and the drive shaft45such that the second gears46brotate idly.

When the shift cam113(FIG. 4) rotates, the shift fork111amoves along the cam grooves113a, and the first gear46amoves in association therewith along the splines of the main shaft44and the drive shaft45in the axial direction. In addition, the engagement protrusions46cof the first gear46aare engaged with the engagement grooves46eof the second gear46b, whereby the combination of the speed gears46,47that transmit driving force from the main shaft44to the drive shaft45is switched, thus performing a gear change.

However, when the shift cam113rotates and the first gear46ahas moved in the axial direction, there are occasions when the engagement protrusions46cof the first gear46ado not engage with the engagement grooves46eof the second gear46b, and instead the engagement protrusions46cabuts against an axial end surface46fof the second gear46bsuch that coupling does not take place properly and clash occurs. In this clashing state, the first gear46aand the second gear46bare not engaged, and thus the first gear46aand the second gear46bremain in an abutting state without the gear change being performed reliably.

As shown inFIG. 3, the hollow main shaft44is supported by a pair of shaft bearings540so as to be freely rotatable. A first push rod527, a ball528, and a second push rod529are inserted inside the main shaft44so as to be movable in the axial direction. When these members move, the pressure plate37cis moved in the left-right direction.

A flange member529bis formed on the second push rod529, and a bearing533is interposed between the flange member529band the pressure plate37c. As a result, in contrast to the second push rod529that is not able to rotate, the pressure plate37ccan rotate.

Rotation of the shift shaft70is converted into reciprocating motion of the first push rod527by a clutch transmission mechanism270.FIG. 6is an expanded cross sectional view showing the clutch transmission mechanism270ofFIG. 3. The clutch transmission mechanism270shown inFIG. 6is a ball cam mechanism that converts rotation of the shift shaft70into reciprocating motion.

The clutch transmission mechanism270is provided with a first cam plate283that rotates along with the shift shaft70, and a second cam plate284that faces the first cam plate283. The first cam plate283is connected to the shift shaft70via a connection pin281. A first cam groove285and a second cam groove286are respectively formed in the opposing faces of the first cam plate283and the second cam plate284.

In addition, the clutch transmission mechanism270is provided with three balls287(inFIG. 6only one is shown) that are sandwiched between the first cam plate283and the second cam plate284. These balls287engage with the first cam groove285and the second cam groove286. The first and the second cam plate283,284have a disc shape. Moreover, the first cam plate283is firmly attached to the shift shaft70.

Furthermore, the second cam plate284is firmly attached to a boss289that can move in the axial direction of the shift shaft70. A pressing plate292is firmly attached to a lower end section of the boss289. The pressing plate292abuts against a pressure lever219, described hereinafter. In addition, a compression coil spring293is interposed between the pressing plate292and the boss289.

A left end section of the pressure lever219abuts against the pressing plate292. In addition, a right end section of the pressure lever219abuts against the first push rod527(FIG. 3). Furthermore, a central section in the longitudinal direction of the pressure lever219is supported by a spindle295. The pressure lever219is able to swing centering on the contact point of the pressure lever219and the spindle295as a fulcrum.

When the shift shaft70rotates in association with rotation of an actuator75(FIG. 3), the first cam plate283also moves in association therewith. Because the second cam plate284does not rotate in association with the shift shaft70, the first cam plate283rotates relatively with respect to the second cam plate284. At this time, the balls287move in the circumferential direction in the cam groove286of the second cam plate284while being held by the cam groove285of the first cam plate283. When the shift shaft70rotates still further, the balls287pass out of the cam groove286and thus leave the cam groove286. As a result of the balls287leaving the cam groove286in this manner, the second cam plate284moves in the axial direction of the shift shaft70. As a result of this movement of the second cam plate284, the left end section of the pressure lever219is pressed against by the boss289.

When the left end section of the pressure lever219is pressed against by the boss289, the pressure lever219swings centering on the connection point with the spindle295as a fulcrum. As a result, the first push rod527is pressed against by the right end section of the pressure lever219. In addition, as a result of the first push rod527being pressed against by the pressure lever219, the first push rod527slides in the rightward direction as shown inFIG. 3. Moreover, the second push rod529is pressed in the rightward direction by the first push rod527via the balls528, and thus slides in the rightward direction.

As shown inFIG. 3, as a result of the second push rod529sliding, the pressure plate37cmoves in the rightward direction against the urging force of the compression spring60. Accordingly, pressurized contact of the friction plates39aand clutch plates39bis released, and the shift clutch37is disengaged.

In this manner, the shift shaft70and the pressure plate37care connected via the pressure lever219, the first push rod527, the balls528, and the second push rod529, and the pressure plate37cmoves in accordance with rotation of the shift shaft70. More specifically, when the shift shaft70starts to rotate, the pressure plate37cmoves in the rightward direction, and when the rotation angle of the shift shaft70reaches a defined angle (clutch disengagement start angle), the shift clutch37is disengaged. Furthermore, when the shift shaft70rotates still further until another defined angle (shift start angle), the shift cam113(FIG. 4) rotates, and the shift operation is performed.

As shown inFIG. 3, abutting members70a,70bthat protrude outwards in the radial direction are respectively formed in the shift shaft70. In addition, stoppers280a,280bthat respectively abut with the abutting members70a,70bare formed in the crank case35. The stoppers280a,280bregulate rotation of the shift shaft70. More specifically, when the shift shaft70rotates in an up-shift direction (reverse rotation), the stopper280aabuts the abutting member70a, thereby regulating rotation of the shift shaft70. On the other hand, when the shift shaft70rotates in a down-shift direction (normal rotation), the stopper280babuts the abutting member70b, thereby regulating rotation of the shift shaft70. The stoppers are not limited to being the stoppers280a,280bshown inFIG. 3. So long as a structure is adopted that can regulate rotation of the shift shaft70, various types of structural members may be used. The rotation angle of the shift shaft70when the stoppers280a,280bregulate rotation is the mechanical maximum rotation angle of the shift shaft70.

As shown inFIG. 3, a flywheel magnet50is attached to a left end section of the crank shaft30. The flywheel magnet50is structured by a rotor of a generator51.

A section of the shift shaft70that protrudes outside the crank case35defines a protruding section70c. As shown inFIG. 2, a section of the drive shaft45that protrudes outwards from the crank case35defines a protruding section45aof the drive shaft45, and a sprocket54is fixed thereto. A chain55that functions as a driving force transmission member is wrapped around this sprocket54and a sprocket (not shown) of the rear wheel26.

FIG. 7is a block diagram that schematically shows the overall structure of a control system of the motorcycle10. An ECU (engine control unit)100is provided with a CPU101that is connected to an up-shift switch102aand a down-shift switch102b. The up-shift switch102aand the down-shift switch102bare provided, for example, on a left handle94of the motorcycle10(FIG. 1), and are switches that are operated by an operator of the motorcycle10to perform a gear change shift (an up-shift or a down-shift).

In addition, a gear position sensor103is connected to the CPU101of the ECU100. The gear position sensor103is a sensor that detects the gear position (a rotational position of the shift cam113). The CPU101uses the rotational position of the shift cam113(FIG. 4) detected by the gear position sensor103as a basis for obtaining the gear position. The gear position sensor103corresponds to a gear position detection device of the invention in the illustrated arrangement.

Moreover, the CPU101is connected to a CDI (Capacitive Discharge Ignition)105via a drive circuit104. The CDI105uses an ignition cut signal supplied via the drive circuit104from the CPU101as a basis for performing ignition cut of the engine29(FIG. 2), thereby reducing driving force of the engine29. In addition, the CDI105detects a rotational speed of the engine29(the engine speed) and supplies the detection result to the CPU101.

Moreover, an actuator75(FIG. 3) is connected to the CPU101via the drive circuit107. The actuator75includes an electric motor (not shown). When the actuator75is driven, the shift shaft70is rotated. The drive circuit107uses a control signal from the CPU101as a basis for performing drive control (PWM (Pulse Width Modulation) control) of the electric motor in the actuator75.

In addition, the CPU101is connected to a rotation angle sensor106. The rotation angle sensor106detects the rotation angle of the shift shaft70(FIG. 3). Note that, the rotation angle sensor106corresponds to a rotation angle detection device of the invention in the illustrated embodiment. The rotation angle sensor106may be a device that directly detects the rotation angle of the shift shaft70or may be a device that indirectly detects the rotation angle, such as through another component that moves along with the shift shaft70.

The gear change shift operation during running of the motorcycle10shown inFIG. 1toFIG. 7is explained with additional reference toFIG. 8.FIG. 8is an explanatory figure that illustrates the gear change shift operation. As shown inFIG. 8, when an up-shift operation is performed (when the up-shift switch102ais operated), the shift shaft70performs a reciprocating rotational motion in which the shift shaft70rotates till its rotation angle is a target angle θmax(up) (reverse rotation), and then returns to a reference angle (0°). On the other hand, when a down-shift operation is performed (when the down-shift switch102bis operated), the shift shaft70performs a reciprocating rotational motion in which the shift shaft70rotates till its rotation angle is a target angle θmax(down) (normal rotation), and then returns to the reference angle (0°).

Note that, here, the target angles θmax(up), θmax(down) are set respectively at the mechanical maximum rotation angles (design values) of the shift shaft70in the reverse rotation direction and the normal rotation direction. The mechanical maximum rotation angles are rotation angles of the shift shaft70when, as described above, the rotation of the shift shaft70is regulated in the reverse rotation direction and the normal rotation direction.

However, both the target angles θmax(up), θmax(down) are design values for the above-described mechanical maximum rotation angles. As a result, there are occasions when the target angles θmax(up), θmax(down) deviate from the actual mechanical maximum rotation angles as a result of design error, assembly error and the like (including normal manufacturing variations) of the structural components of the clutch transmission mechanism270.

While the shift shaft70performs reciprocating rotational motion, a series of gear change shift operations is performed, including, disengagement of the shift clutch37, gear change of the speed change device38, and engagement of the shift clutch37.

The gear change shift operation is explained in more detail with reference toFIG. 9.FIG. 9is a flow chart showing a gear change shift control process. This gear change shift control process is executed when it is invoked from a main routine that is already being executed when a gear change shift operation is performed, that is, when the up-shift switch102aor the down-shift switch102bis operated.

When the gear change shift control process starts, first, at block S100, processing is performed that starts disengagement of the shift clutch37. In this processing, the ECU100controls the drive of the actuator75to start rotation of the shift shaft70, whereby the disengagement of the shift clutch37is started. Note that, at block S100, the shift shaft70rotates at the maximum rotational speed.

Once the processing at block S100has been performed, next, return condition determination processing is performed at block S110. In this processing, the ECU100determines whether or not a return condition, which is a condition for shifting to the engagement process of the shift clutch37, is satisfied. This return condition determination processing is explained in greater detail hereinafter with reference toFIG. 10.

Once the processing at block S110has been performed, next, it is determined whether the return condition is satisfied at block S120. In this processing, the ECU100determines whether or not a return condition satisfied flag, which indicates whether the return condition is satisfied, is ON. The return condition satisfied flag is set in the return condition determination processing at block S110described above. When it is determined that the return condition is not satisfied, the processing returns to block S110and waits until the return condition is satisfied.

On the other hand, when it is determined that the return condition is satisfied at block S120, next, engagement of the shift clutch37is performed at block S130. In this processing, the ECU100supplies a drive signal to the actuator75, whereby the actuator75engages the shift clutch37. Note that, at block S130, from when engagement of the shift clutch37is started until when a defined clutch position is reached, half clutch control is performed in which the shift clutch37is gradually engaged. Once the processing at block S130has been performed, the gear change shift control process is ended.

FIG. 10is used to explain the return condition determination processing that is invoked and executed at block S110of the flow chart shown inFIG. 9. Basically speaking, this return condition determination processing performs two determinations, namely, an abutting state determination in which it is determined whether or not the rotation angle of the shift shaft70has reached the θMAX(up) or θMAX(down) that are the actual mechanical maximum rotation angles, and a target achievement determination in which it is determined whether or not the rotation angle of the shift shaft70has reached the target angles θmax(up) or θmax(down). In addition, if either one of the two determinations is satisfied, it is taken that the return condition has been satisfied, and the above-described return condition satisfied flag is set to ON.

Once the return condition determination processing has started, first, at block S300, a number of times n at which a change amount (an angle change amount) of the rotation angle of the shift shaft70has become tiny (or zero) is read. Here, the ECU100calculates in a separate process an angle change amount p per a particular time period t1when the rotation angle of the shift shaft70has become equal to or more than a defined value a or b (a, b are respective defined values when the shift shaft70has rotated in the reverse rotation direction or the normal rotation direction). Note that, the calculation of the angle change amount p is performed based on the detection result of the rotation angle sensor106(FIG. 7). In addition, each time the angle change amount p is calculated, the ECU100determines whether or not the angle change amount p is equal to or less than a defined value po, and counts up the number of times n that the angle change amount p is successively equal to or less than the defined value po. At block S300, the ECU100reads the counted number of times n.

Once the processing at block S300has been performed, next, at block S310, the abutting state determination is performed. In this processing, the ECU100determines whether or not the number of times n read at block S300is equal or more than a defined value n1. When the processing at block S310is performed, the ECU100functions as a first determination device of the invention in the illustrated arrangement.

Here, the fact that the angle change amount p of the shift shaft70has become tiny (equal to or less than the defined value po) indicates that the rotation of the shift shaft70is being regulated. Furthermore, the fact that the rotation number at which the angle change amount p becomes tiny is equal to or more than the defined rotation number n1indicates that the rotation of the shift shaft70is being regulated throughout a determined period. In this embodiment, when the rotation of the shift shaft70is regulated throughout the determined period, it is determined that the shift shaft70has abutted against some other member.

FIG. 11is an explanatory view that illustrates the magnitude of the above-described defined values a, b of the present embodiment. In the embodiment, as shown inFIG. 11, the defined value a is larger than a rotation angle that is intermediate between the reference angle (0°) and the target angle θmax(up). As a result, when the rotation angle of the shift shaft70becomes equal to or more than the defined value a, the rotation angle becomes comparatively closer to the actual mechanical maximum rotation angle θMAX(up). In addition, similarly, when the rotation angle of the shift shaft70becomes equal to or more than the defined value b, the rotation angle becomes comparatively closer to the actual mechanical maximum rotation angle θMAX(down). Note that, in the present invention, the defined values a, b are not limited to the values shown inFIG. 11. More specifically, the defined value a may be smaller than the rotation angle that is intermediate between the reference angle (0°) and the target angle θmax(up). In addition, the defined value b may be smaller than the rotation angle that is intermediate between the reference angle (0°) and the target angle θmax(down).

In this embodiment, in addition to the determination condition described above for determining whether the shift shaft70has abutted against some other member, another determination condition is set, namely, whether or not the rotation angle of the shift shaft70at the time when the shift shaft70has abutted against some other member is near to the mechanical maximum rotation angle. Accordingly, if it is determined that the shift shaft70is abutting against some other member, and also determined that the rotation angle of the shift shaft70is near to the mechanical maximum rotation angle, it is determined that the shift shaft70has reached the mechanical maximum rotation angle. More specifically, it is determined that the shift shaft70is abutting against the stopper280aor280b(refer toFIG. 3). In this manner, as a result of setting the condition that the rotation angle of the shift shaft70is equal to or more than the defined value a or b, it is possible to more accurately determine that the rotation angle of the shift shaft70has reached the mechanical maximum rotation angle.

When it is determined at block S310that the number of times n is equal to or more than the defined value n1(that the shift shaft70is abutting against the stopper280aor280b), next, the return condition satisfied flag is set to ON at block S340. Once the return condition satisfied flag is set to ON, the processing at block S130of the gear change shift control process (FIG. 9) performs engagement of the shift clutch37. Following the processing of block S340, the return condition determination processing is ended.

On the other hand, if it is determined at block S310that the number of times n is not equal to or more than the defined value n1(i.e., is less than n1), next, the time period t for which the rotation angle has been equal to or more than the target angle is read at block S320. Here, the ECU100measures in a separate process the time period t for which the rotation angle θ of the shift shaft70has been equal to or more than the target angle θmax(up) or θmax(down). Note that, the determination as to whether the rotation angle θ is equal to or more than the target angle is made based on the detection result of the rotation angle sensor106(FIG. 7). At block S320, the ECU100reads the measured time period t.

Following the processing at block S320, next, target achievement determination is performed at block S330. In this processing, the ECU100determines whether the time period t read at block S320is equal to or more than a defined value t2. When the processing of block S330is performed, the ECU100functions as a second determination device of the invention in the illustrated arrangement.

If it is determined that the time period t is equal to or more than the defined value t2at block S330, next, the above-described processing at block S340is performed, and the return condition satisfied flag is set to ON. On the other hand, if it is determined that the time period t is not equal to or more than the defined value t2at block S330(i.e., is less than t2), the return condition determination processing is ended. At this time, the processing at block S340is not performed and the return condition satisfied flag is held at OFF.

Note that, in this embodiment, the target angles θmax(up), θmax(down) are respectively set at the mechanical maximum rotation angles (the design values) of the shift shaft70. As described above, there are occasions when the actual mechanical maximum rotation angles θMAX(up), θMAX(down) deviate from the above-described design values due to design error, assembly error and the like (including normal manufacturing variations) of the structural members of the clutch transmission mechanism270(FIG. 3). However, in this embodiment, when the rotation angle of the shift shaft70is equal to or more than the target value throughout the determined or defined time period t2, the return determination satisfied flag is set to ON. More specifically, after the rotation angle of the shift shaft70has definitely exceeded the target angle, engagement of the shift clutch37(reverse rotation of the shift shaft70) is started. As a result, it is possible to reliably perform a gear change shift.

As explained above, in the motorcycle10according to the illustrated embodiment, first, the number of times n is calculated, namely, the number of times n that the angle change amount p per determined or defined time period t1is successively equal to or less than the defined value po when the rotation angle θ of the shift shaft70is equal to or more than the defined value a or b. In addition, the abutting state determination is performed that determines whether or not the number of times n is equal to or more than the defined value n1. If it is determined that there is an abutting state (namely, the shift shaft70has reached the actual mechanical maximum rotation angle), then the processing shifts to the engagement process of the shift clutch37. In this manner, in this embodiment, even if the actual mechanical maximum rotation angles θMAX(up), θMAX(down) deviate from the above-described design values due to design error, assembly error and the like (including normal manufacturing variations) of the structural members of the clutch transmission mechanism270(FIG. 3), engagement of the shift clutch37is started by reverse rotation of the shift shaft70when the rotation angle of the shift shaft70reaches the actual mechanical maximum rotation angle. As a result, regardless of whether or not there are any design errors or assembly errors (including normal manufacturing variations), gear change shift can be performed reliably.

In addition, in this embodiment, the angle change amount p when the rotation angle θ of the shift shaft70is equal to or more than the defined value a or b is used as a basis for determining the abutting state. As a result, it is possible to more accurately determine that the rotation angle of the shift shaft70has reached the mechanical maximum rotation angle.

Moreover, in the motorcycle10according to the illustrated embodiment, the target achievement determination is performed that determines whether or not the rotation angle θ of the shift shaft70is equal to or more than target angle θmax(up) or θmax(down) for equal to or more than the defined time period t2. In addition, in this target achievement determination, when it is determined that the target angle has been reached, the processing shifts to the engagement process of the shift clutch37. In this manner, in this embodiment, even if the actual mechanical maximum rotation angles θMAX(up), θMAX(down) deviate from the design values due to design error, assembly error and the like (including normal manufacturing variations) of the structural members of the clutch transmission mechanism270, engagement of the shift clutch37is started by reverse rotation of the shift shaft70when the rotation angle of the shift shaft70has definitely exceeded the target angle. As a result, regardless of whether or not there are any design errors or assembly errors (including normal manufacturing variations), a gear change shift can be performed reliably.

Note that, this embodiment may adopt a configuration in which, if a defined wait time elapses without either one of the abutting state determination (FIG. 10, block S310) or the target achievement determination (block S330) being satisfied, it is determined that an abnormality of the rotation angle sensor106or the like has occurred, and the processing shifts to the engagement process of the shift clutch37without the determinations being satisfied. In addition, the embodiment may also be configured such that, in the case that the processing shifts to the engagement process of the shift clutch37based on the determination that an abnormality has occurred, a determined abnormality warning is issued. The method used for this abnormality warning is not particularly limited. For example, it is possible to use a method in which a display that indicates the occurrence of the abnormality is displayed on an indicator (a display device) or a method in which a warning lamp lights or flashes.

Second Embodiment

In the above-described first embodiment, when either one of the two determinations, namely, the abutting state determination (FIG. 10, block S310) and the target achievement determination (FIG. 10, block S330), is satisfied, engagement of the shift clutch37is started. In contrast, in a second embodiment described below, instead of the above-described target achievement determination, a gear change determination is performed in which it is determined whether or not the gear change is completed. Moreover, when either one of the two determinations, namely, the abutting state determination and the gear change determination is satisfied, the engagement of the shift clutch37is started.

FIG. 12is a flow chart showing the flow of return condition determination processing according to the second embodiment. In the return condition determination processing shown inFIG. 12, processes that are the same as those of the return condition determination processing ofFIG. 10are denoted with the same reference numerals. An explanation of these processes is omitted here. In addition, in the motorcycle according to the second embodiment, the processes other than those shown inFIG. 12, the structural members and the devices etc. are the same as, or substantially similar to, those in the motorcycle10according to the first embodiment. Accordingly, an explanation of these details is omitted here.

In the return condition determination processing shown inFIG. 12, instead of the processing of blocks S320, S330in the return condition determination processing shown inFIG. 10, the processing of block S420is performed. In block S420, the ECU100determines whether or not the gear change is completed. In this processing, the ECU100determines whether or not the gear change of the speed change device38is completed based on the detection result of the gear position sensor103. During performance of the processing of block S420, the ECU100functions as a third determination device of the invention in the illustrated arrangement. If it is determined that the gear change is completed at block S420, the processing proceeds to the processing of block S340. On the other hand, if it is determined that the gear change is not completed, the return condition determination processing is ended. At this time, the return condition satisfied flag is not set to ON, and is held at OFF.

As explained above, in the second embodiment, when either one of the two determinations, namely, the abutting state determination (block S310) or the gear change determination (block S420), is satisfied, engagement of the shift clutch37is started. Accordingly, in this embodiment, if it is determined that the gear change is completed prior to when the rotation angle of the shift shaft70has reached the actual mechanical maximum rotation angles θMAX(up), θMAX(down), engagement of the shift clutch37is started. As a result, it is possible to shorten the time it takes to perform gear change shift. In addition, as in the first embodiment, gear change shift can be performed reliably regardless of whether or not there are any design errors or assembly errors (including normal manufacturing variations) of the structural members of the clutch transmission mechanism270.

Note that, this embodiment may adopt a configuration in which, if a defined wait time elapses without either one of the abutting state determination (FIG. 12, block S310) or the gear change determination (block S420) being satisfied, it is determined that an abnormality of the rotation angle sensor106or the like has occurred, and the processing shifts to the engagement process of the shift clutch37without the determinations being satisfied. In addition, the embodiment may also be configured such that, in the case that the processing shifts to the engagement process of the shift clutch37based on the determination that an abnormality has occurred, a abnormality warning is issued. The method used for this abnormality warning is not particularly limited. For example, it is possible to use a method in which a display that indicates the occurrence of the abnormality is displayed on an indicator (a display device) or a method in which a warning lamp lights or flashes.

Third Embodiment

In a third embodiment described herein below, only the abutting state determination is performed in the return condition determination processing. In addition, when the abutting state determination is satisfied, engagement of the shift clutch37is started.

FIG. 13is a flow chart showing the flow of return condition determination processing according to the third embodiment. In the return condition determination processing shown inFIG. 13, processes that are the same as, or substantially similar to, those in the return condition determination processing shown inFIG. 10are denoted with the same reference numerals. In addition, in the motorcycle according to the third embodiment, the processes other than those shown inFIG. 13, the structural members and the devices etc. are the same as, or similar to, those in the motorcycle10according to the first embodiment. Accordingly, an explanation of these details is omitted.

In the return condition determination processing shown inFIG. 13, in the abutting state determination of block S310, if the number of times n is equal to or more than the defined value n1, the processing proceeds to the processing of block S340. On the other hand, if the number of times n in block S310is not equal to or more than the defined value n1, the return condition determination processing is ended.

As described above, in the third embodiment, engagement of the shift clutch37is started when the abutting state determination (block S310) is satisfied. As a result, even if the actual mechanical maximum rotation angles θMAX(up), θMAX(down) deviate from the design values due to design error, assembly error and the like (including normal manufacturing variations) of the structural members of the clutch transmission mechanism270, engagement of the shift clutch37is started by reverse rotating the shift shaft70when the rotation angle of the shift shaft70reaches the actual mechanical maximum rotation angle. As a result, regardless of whether or not there are any design errors or assembly errors (including normal manufacturing variations), a gear change shift can be performed reliably.

Note that, this embodiment may adopt a configuration in which, if a defined wait time elapses without the abutting state determination (FIG. 13, block S310) being satisfied, it is determined that an abnormality of the rotation angle sensor106or the like has occurred, and the processing shifts to the engagement process of the shift clutch37without the determination being satisfied. In addition, the embodiment may also be configured such that, in the case that the processing shifts to the engagement process of the shift clutch37based on the determination that an abnormality has occurred, a determined abnormality warning is issued. The method used for this abnormality warning is not particularly limited. For example, it is possible to use a method in which a display that indicates the occurrence of the abnormality is displayed on an indicator (a display device) or a method in which a warning lamp lights or flashes.

Fourth Embodiment

In the above-described first to third embodiments, if it is determined that the rotation of the shift shaft70is being regulated throughout the defined time period, it is determined that the rotation angle of the shift shaft70has reached the mechanical maximum rotation angle. However, the rotation of the shift shaft70is regulated not only when the rotation angle of the shift shaft70reaches the mechanical maximum rotation angle, but also when the above-described gear clash occurs. In a fourth embodiment described below, a clash determination device (a fourth determination device) is provided. If the rotation of the shift shaft70is regulated, the clash determination device determines whether the regulation is caused by the shift shaft70abutting against the stopper280aor stopper280b(namely, reaching the mechanical maximum rotation angle) or by the occurrence of clash. In addition, if it is determined that the regulation is caused by clash, control is performed to end the clashing state.

FIG. 14shows the transition in the rotation speed of the shift shaft70over time in the engagement process of the shift clutch37. Note that,FIG. 14just illustrates the case of a downshift. As described above, the ECU100performs PWM control of the electric motor provided in the actuator75(FIG. 3). In the PWM control, the duty ratio (the ratio of the energized time per unit time) of the drive voltage of the electric motor is changed to determine the rotation speed of the electric motor. More specifically, in the PWM control, the duty ratio is changed to change the rotation speed (rotational driving force) of the shift shaft70. For example, if the duty ratio is 0%, the rotation speed of the shift shaft70is zero, and if the duty ratio is 100%, the rotational speed of the shift shaft70is the maximum rotational speed.

As shown inFIG. 14, in this embodiment, in the engagement process of the shift clutch37, the duty ratio is set high (inFIG. 14, the duty ratio is 100%) from when the shift shaft70starts to rotate until when the rotation angle of the shift shaft70approaches close to the target angle θmax(down). Then, the duty ratio is reduced from when the rotation angle of the shift shaft70approaches close to the target angle θmax(down) to when the target angle θmax(down) is reached. As a result, the rotation speed of the shift shaft70reduces. In addition, when the target angle is reached, the duty ratio is set to 0%, and rotation of the shift shaft70stops.

Note that, in the case that the shift shaft70is abutting against the stopper280aor280b, the shift shaft70will abut in the region in the vicinity of the target angle. As a result, the duty ratio when the shift shaft70abuts will be small. On the other hand, as shown by the dot-dash line inFIG. 14, if clash occurs at a rotation angle between the reference angle (0°) and the target angle θmax(down), the shift shaft70will abut when the duty ratio is high. In this embodiment, this difference in the duty ratio when the shift shaft70abuts is used as a basis for determining whether the shift shaft70has reached the mechanical maximum rotation angle or clash has occurred.

FIG. 15is a flow chart that shows the flow of clash determination processing according to the fourth embodiment. The clash determination processing is a process that starts when it is determined that the shift shaft70is abutting in the abutting state determination of the processing of block S310(FIG. 10,FIG. 12, andFIG. 13) (YES in S310). Note that, in the motorcycle according to the fourth embodiment, processes other than those shown inFIG. 15, the structural members and the devices etc. are the same as those in the motorcycles according to the first, second and third embodiments. Accordingly, an explanation of these details is omitted.

When the clash determination processing starts, first, at block S500, it is determined whether or not a duty ratio d is equal to or more than a defined value D1. In this processing, if it is determined that the duty ratio is high (equal to or more than the defined value D1), it is determined that clash has occurred. On the other hand, if the duty ratio is low (less than the defined value D1), it is determined that clash has not occurred. In this case, since it is determined that the shift shaft70is abutting at block S310, it can be determined that the abutting state of the shift shaft70is not caused by clash, but is caused by the shift shaft70abutting against the stopper280aor the stopper280b.

In the case that it is determined at block S500that the duty ratio is not equal to or more than the defined value D1(ie, is less than D1), it can be determined that the shift shaft70has reached the mechanical maximum rotation angle, and thus the ECU100proceeds to the processing of block S340(refer toFIG. 10,FIG. 12, andFIG. 13).

On the other hand, if it is determined that the duty ratio is equal to or more than the defined value D1at block S500, it can be determined that clash has occurred, and thus the ECU100proceeds to the processing of block S510that relates to ending the clashing state. At block S510, the ECU100first sets a duty ratio of 0% for just a defined time period t3. As a result of this processing, the rotational driving force of the shift shaft70becomes substantially zero. As a result, the force pushing the first gear46ato the second gear46b(FIG. 5) becomes substantially zero. When the pushing force applied to the second gear46bbecomes substantially zero, the engine driving force transmitted to the main shaft44and the drive shaft45(FIG. 2) causes the first gear46aand the second gear46bto rotate relative to each other.

After the duty ratio has been set to 0% for the defined time period t3at block S510, the ECU100sets the duty ratio to a defined value D2(0<D2<D1). As a result, the pushing force on the second gear46bis generated once again. Accordingly, in the processing of block S510, after the first gear46aand the second gear46bhave been rotated relative to each other, the first gear46ais pressed toward the second gear46bin this manner. As a result, the clashing state can be ended easily.

Following the processing of block S510, next, in block S520, the processing waits a defined time period t4. In this processing, the ECU100waits the defined time period t4with the duty ratio held set at the defined value D2as a result of the processing of block S510.

Following the processing of block S520, next, at block S530, it is determined whether the clashing state has ended. The method used for determining whether the clashing state has ended is not particularly limited. For example, the method described below may be used. First, as one example, a method in which it is determined whether or not gear change is completed may be used. More specifically, in the case that it is determined that the gear change of the speed gear47is completed based on the detection result of the gear position sensor103, it can be determined that the clashing state has ended. Alternatively, it is possible to use another method that utilizes the abutting state determination. As an example of such a method using the abutting state determination, for example, a method may be used in which the angle change amount of the shift shaft70per a defined time period is calculated, and then it is determined whether or not the number of times when the angle change amount has become tiny (or zero) has continued for a defined number of times.

At block S530, if it is determined that the clashing state has ended, the ECU100returns to the processing of block S310(FIG. 10,FIG. 12, andFIG. 13). On the other hand, if it is determined that the clashing state has not ended at block S530, the ECU100returns to the processing of block S510. Then, as a result of the processing of blocks S510, S520, the processing related to ending the clashing state is performed again.

As described above, in the fourth embodiment, when the shift shaft70is in the abutting state, it is determined whether or not the abutting state is caused by the shift shaft70reaching the mechanical maximum rotation angle or by the occurrence of clash. In addition, in the case that it is determined that there is a clashing state, processing is performed that ends the clashing state. As a result, it is possible to perform gear change shift even more reliably.

Other Embodiments

The first to fourth embodiments may be appropriately combined to carry out the invention. The shift control device according to the present invention may include the first determination device, the second determination device and the third determination device. In addition, during the disengagement process of the shift clutch37, when it is determined that the determinations of the first determination device, the second determination device and the third determination device are satisfied, the processing may shift to the engagement process of the shift clutch37. In addition, if none of the determinations of the first determination device, the second determination device and the third determination device are satisfied between the time when the disengagement process of the shift clutch37is started and when the defined time period elapses, the processing may shift to the engagement process of the shift clutch37.

A configuration may also be adopted in which, when the determination of the first determination device is satisfied and the rotation angle of the shift shaft70is equal to or more than a first angle and less than a second angle (which is > the first angle) during the disengagement process of the shift clutch37(FIG. 14), the fourth determination device determines that clash has occurred.

In addition, a configuration may also be adopted in which, when the determination of the first determination device is satisfied, the rotation angle of the shift shaft70is equal to or more than the first angle and less than the second angle, and the determination of the third determination device is not satisfied during the disengagement process of the shift clutch37, the fourth determination device determines that clash has occurred.

As described above, the invention can be favorably used for a shift control device and a vehicle incorporating a shift control device.

Although this invention has been disclosed in the context of certain preferred embodiments and examples, it will be understood by those skilled in the art that the present invention extends beyond the specifically disclosed embodiments to other alternative embodiments and/or uses of the invention and obvious modifications and equivalents thereof. In particular, while the present shift control device has been described in the context of particularly preferred embodiments, the skilled artisan will appreciate, in view of the present disclosure, that certain advantages, features and aspects of the shift control device may be realized in a variety of other applications, many of which have been noted above. Additionally, it is contemplated that various aspects and features of the invention described can be practiced separately, combined together, or substituted for one another, and that a variety of combination and subcombinations of the features and aspects can be made and still fall within the scope of the invention. Thus, it is intended that the scope of the present invention herein disclosed should not be limited by the particular disclosed embodiments described above, but should be determined only by a fair reading of the claims.