JP2008298089A - Axle-motion device mounting structure - Google Patents

Abstract

Provided is an attachment structure for an axial movement device that can be reduced in size while being provided with the axial movement device.
An axial movement device in which an axial movement device 55 in which a fixed portion holds an axial portion 56 that engages and interlocks with a rotating member 40 rotatably supported by cases 2L and 2R is fixedly held in the case 2L. In the mounting structure of 55, a recessed portion 41 is formed on at least one end surface of the rotating member 40 in the rotational axis direction, and the axially moving device 55 is disposed inside the recessed portion 41 of the rotating member 40. .
[Selection] Figure 5

Description

  The present invention relates to a mounting structure for an axial movement device that performs a predetermined function by rotating or axially moving a shaft portion engaged with a rotating member.

A rotation angle detector or the like that detects the rotation angle of a rotating member as an axial movement device is usually outside the rotating member and detects rotation by engaging with the rotating shaft or detecting movement of the outer periphery of the rotating member. is doing.
For example, a detector that detects the rotation angle of the shift drum of the transmission is disposed on the side of the rotation center axis of the shift drum (see, for example, Patent Document 1).

Japanese Utility Model Publication No. 60-141503

  In the rotation angle detector disclosed in Patent Document 1, the rotation operation shaft of the rotation angle detector is fitted onto the rotation shaft formed on one end of the shift drum so as to rotate integrally. Is engaged.

  As for the rotation of the shift drum, the rotation angle is detected by integrally rotating the rotation operation shaft of the rotation angle detector.

Thus, since the rotation angle detector is disposed on the side of the rotation shaft of the shift drum, the case for supporting the shift drum and the rotation angle detector has been enlarged.
That is, by providing the rotation angle detector outside the rotating member, the case for supporting them is increased in size.

  The present invention has been made in view of the above points, and the object of the present invention is to provide an attachment structure for an axial movement device capable of reducing the size of the case while including the axial movement device.

  In order to achieve the above object, according to the first aspect of the present invention, an axial motion device in which a fixed portion holds a shaft portion that engages and interlocks with a rotating member that is rotatably supported by the case is fixed to the case. In the mounting structure of the axial movement device to be held, a concave portion is formed on at least one end surface of the rotating member in the rotation axis direction, and the axial movement device is disposed inside the concave portion of the rotating member. It was set as the attachment structure of the axial movement equipment.

  According to a second aspect of the present invention, in the mounting structure for an axial movement device according to the first aspect, the cylindrical support portion protruding from the case is inserted into the recessed portion of the rotating member, and the outer peripheral surface of the cylindrical support portion The rotating member is rotatably supported, and a fixed portion of the axial motion device is fitted and held on an inner peripheral surface of the cylindrical support portion.

  According to a third aspect of the present invention, in the mounting structure for an axial movement device according to the first or second aspect, the shaft portion of the axial movement device is formed on a rotation center axis in the recessed portion of the rotating member. It is characterized by being engaged with a dynamic connecting part.

  According to a fourth aspect of the present invention, in the attachment structure for an axial motion device according to any one of the first to third aspects, the rotating member is a shift drum of a transmission.

  According to a fifth aspect of the present invention, in the mounting structure for an axial movement device according to the fourth aspect, at least two shift forks are engaged with one lead groove formed on the outer peripheral surface of the shift drum. It is characterized by.

  According to a sixth aspect of the present invention, in the mounting structure for an axial movement device according to the fourth or fifth aspect, a bolt hole is formed on the rotation center shaft of the shift drum opposite to the recessed portion, A speed change feed member of the speed change intermittent feed mechanism is fixed to the shift drum by a bolt screwed into the bolt hole, the rotation connecting portion protrudes on the rotation center shaft, and the shaft portion is engaged with the rotation connection portion. It is characterized by that.

  According to a seventh aspect of the present invention, in the mounting structure for an axial movement device according to any one of the first to sixth aspects, the axial movement device is a rotation detector that detects a rotation state of the rotating member. It is characterized by being.

  According to an eighth aspect of the present invention, in the mounting structure for an axial movement device according to any one of the first to fifth aspects, the axial movement device is a rotary driving machine that rotates the rotating member. Features.

  According to the mounting structure of the axial movement device according to claim 1, since the concave portion is formed on at least one end surface of the rotation member in the rotation axis direction, and the axial movement device is disposed inside the concave portion of the rotation member. Axial motion devices can be mounted on the rotating member in a compact manner, and the case supporting them can be miniaturized.

  According to the mounting structure for an axial movement device according to claim 2, the cylindrical support portion protruding from the case is inserted into the recessed portion of the rotating member, and the rotating member is rotatably supported on the outer peripheral surface of the cylindrical support portion. In addition, since the axial movement device is fitted and held on the inner peripheral surface, the axial movement device has a simple structure with a small number of parts that does not have a dedicated part for supporting the axial movement device by using the cylindrical support portion in common. The rotating member can be equipped compactly, and the case can be reduced in size and weight.

  According to the mounting structure of the axial movement device of the third aspect, the shaft portion of the axial movement device engages with the rotation connecting portion formed on the rotation center shaft in the recessed portion of the rotating member. The engaging part of the dynamic connecting part is in the recessed part of the rotating member to be protected.

  According to the mounting structure for an axial motion device according to claim 4, since the rotating member is a shift drum of the transmission, the axial motion device is compactly installed in the recessed portion of the shift drum, and the crankcase for supporting these is small. Can be achieved.

  According to the structure for mounting an axial movement device according to claim 5, since at least two shift forks are engaged with one lead groove of the lead groove formed on the outer peripheral surface of the shift drum, the required number of shift stages is ensured. However, the lead groove of the shift drum can be reduced, the shift drum itself can be shortened in the axial direction, and the case can be downsized.

  According to the mounting structure for an axial movement device according to claim 6, the shift drum of the transmission has a rotational connection in which the transmission member of the transmission mechanism is fixed on the rotation center shaft by the bolt and protrudes on the rotation center shaft. Since the shaft portion of the axial movement device is engaged with the portion, the axial movement device can sufficiently function with a simple configuration.

  According to the mounting structure for an axial movement device according to claim 7, since the axial movement apparatus is a rotation detector that detects the rotation state of the rotation member, the rotation detector can be compactly equipped on the rotation member. It is possible to reduce the size of the case that supports the.

  According to the mounting structure for an axial movement device according to claim 8, since the axial movement apparatus is a rotary drive machine that rotates the rotary member, the rotary drive machine can be compactly equipped on the rotary member, and these are supported. The case can be downsized, and the internal combustion engine can be downsized.

Hereinafter, an embodiment according to the present invention will be described with reference to FIGS.
The internal combustion engine 1 of the present embodiment is a four-cycle single-cylinder internal combustion engine, and is mounted horizontally on a motorcycle with a crankshaft oriented in the horizontal direction.
In the present specification, the forward direction of the motorcycle is defined as the forward direction, and the front, rear, left and right are determined based on the posture facing forward.

The crankcase 2 of the internal combustion engine 1 is divided into left and right parts, and the cylinder block 3 projecting upward so as to be sandwiched between the left and right crankcases 2L and 2R has a cylinder shaft which is the central axis of the cylinder bore. The cylinder head is slightly tilted forward, and a cylinder head is overlaid on the cylinder block 3.
A left case cover 4L is placed on the left side of the front half of the left crankcase 2L, and a right case cover 4R is placed on the right side of the right crankcase 2R (see FIG. 3).

FIG. 1 is a schematic left side view showing the inside of the internal combustion engine 1 with the upper part of the cylinder block 3 of the internal combustion engine 1 omitted, the left crankcase 2L removed, and the cylinder block 3 taken as a cross section. A mating surface with the left crankcase 2L is displayed.
FIG. 2 is a schematic right side view in which the upper part of the cylinder block is omitted and the right case cover 4R is removed, and the mating surface of the right crankcase 2R with the right case cover 4R is displayed.
The direction indicated by the arrow Fr is the front.

  A crank chamber 2c is formed in the front half of the crankcase 2 and a transmission chamber 2m is formed in the rear half thereof. A transmission mechanism 20 is provided in the mission chamber 2m.

  A connecting rod in which a piston 6 is slidably provided in a cylinder bore of the cylinder block 3, and a large end is pivotally supported by a crank pin 5p provided on the opposite side of the crank weight 5w with respect to the rotation center axis of the crank shaft 5. 7 extends into the upper cylinder bore, and a small end portion of the tip is pivotally supported by a piston pin 6p of the piston 6, and the crankshaft 5 and the piston 6 are connected by a connecting rod 7 to constitute a piston / crank mechanism.

  Referring to FIG. 3, outer rotor 13r of AC generator 13 is fitted to the left end of crankshaft 5 that protrudes to the left from left crankcase 2L, and power is generated on left case cover 4L that covers AC generator 13 from the left. An inner stator 13s having a coil is supported and disposed in the outer rotor 13r.

  On the other hand, the transmission mechanism 20 accommodated in the transmission chamber 2m is a constantly meshing gear transmission, and the main shaft 21 is rotated to the left and right crankcases 2L and 2R via bearings 22 and 22 behind the crankshaft 5. The counter shaft 23 is rotatably supported on the left and right crankcases 2L and 2R via bearings 24 and 24 at a slightly obliquely lower position further rearward of the main shaft 21.

  Five transmission gears m1 to m5 having a gear ratio from 1st speed to 5th speed are supported on the main shaft 21 in the transmission chamber 2m, and the transmission gears m1 to m5 correspond to the transmission gears m1 to m5. n1 to n5 are pivotally supported, and the corresponding transmission gears are engaged with each other.

  Referring to FIG. 4, the engagement between the first speed gears m1 and n1 having the largest speed ratio is arranged on the rightmost side along the right side wall of the mission chamber 2m, and the engagement between the second speed gears m2 and n2 is the transmission. Arranged on the leftmost side along the left side wall of the chamber M, between the first gear m1, n1 and the second gear m2, n2, the third gear m3, n3, fourth gear m4, n4, fifth gear m5 , N5 are arranged.

  Of these, the third speed gear m3 on the main shaft 21 is spline-fitted to the main shaft 21 and moves in the axial direction as a shifter, and when moved to the left, the fourth speed gear m4 and the engaging portions c4 and c4 ′ are connected to each other. Engagement establishes the fourth speed, and when moving to the right, the fifth speed gear m5 and the engaging portions c5, c5 ′ are engaged to establish the fifth speed.

Further, the fifth speed gear n5 on the counter shaft 23 is spline fitted to the counter shaft 23 to become a shifter and moves in the axial direction. When the right speed gear n5 moves to the right side, the first speed gear n1 and the engaging portions c1 and c1 'are mutually connected. Engage to establish the first speed and move to the left side to establish the third speed by engaging the third speed gear n3 and the engaging portions c3 and c3 ′.
Further, the 4th speed gear n4 on the counter shaft 23 is spline fitted to the counter shaft 23 and moves in the axial direction as a shifter. Engage to establish second gear.

  As described above, the third speed gear m3 on the main shaft 21 serving as a shifter and the fourth speed gear n4 and the fifth speed gear n5 on the counter shaft 23 are moved by the speed change drive mechanism 30 to change the speed.

  A large-diameter clutch outer 15o of a multi-plate friction clutch 15 is supported via a one-way clutch 16 at the right end of the main shaft 21 protruding rightward from the mission chamber 2m, and rotates together with the clutch outer 15o. Is engaged with a primary drive gear 14a fitted to the right end of the crankshaft 5 protruding from the right crankcase 2R to form a primary reduction mechanism.

  The clutch inner 15i which is the output side of the friction clutch 15 is spline-fitted to the main shaft 61, and therefore the rotation of the crankshaft 5 is transmitted to the main shaft 21 via the primary reduction mechanisms 14a and 14b and the friction clutch 15. The

  The counter shaft 23 to which power is transmitted through the speed change mechanism 20 from the main shaft 21 is an output shaft that penetrates the left crankcase 2L to the left, and a drive sprocket 25 is fitted to the left end thereof. The chain 26 wound around the drive sprocket 25 extends rearward and transmits power to the rear wheels.

  As shown in FIG. 1, a shift drive mechanism 30 for driving a transmission mechanism 20 is constructed such that shift fork shafts 31 and 32 are respectively supported between left and right crankcases 2L and 2R below a main shaft 21 and a counter shaft 23. One shift fork 33 supported on the front shift fork shaft 31 so as to be slidable in the axial direction is engaged with a third speed gear m3 which is a shifter on the main shaft 21, and the rear shift fork shaft 32 is engaged. Two shift forks 34 and 35 supported so as to be slidable in the axial direction engage with a fourth speed gear n4 and a fifth speed gear n5 which are shifters on the counter shaft 23, respectively.

A shift drum 40 is rotatably supported between the left and right crankcases 2L, 2R between the front and rear shift fork shafts 31, 32.
Referring to FIG. 5, the shift drum 40 has a substantially bottomed cylindrical shape with a concave portion 41 opened to the left, and a bolt boss portion with a bolt hole 42b carved on the rotation center axis at the right bottom portion. 42 is formed, and a cylindrical connecting protrusion 43 protrudes from the bolt boss part 42 into the left recessed part 41 on the rotation center axis to the center in the left-right direction of the recessed part 41. A cut groove 43v having a predetermined width is formed in the portion (see FIG. 7).
Two lead grooves 44 and 45 are formed on the outer peripheral surface of the shift drum 40 in the circumferential direction.

A cylindrical support portion 50 protruding rightward from the left crankcase 2L is inserted into the opening of the left-end concave portion 41 in the shift drum 40, and the inner peripheral surface of the concave portion 41 is inserted into the outer peripheral surface of the cylindrical support portion 50. And the left end of the shift drum 40 is supported, and the right end of the shift drum 40 is pivotally supported by a bolt boss portion 42 on the side wall of the right crankcase 2R via a ball bearing 52. As a result, the shift drum 40 is rotatably mounted on the left and right crankcases 2L, 2R.
Needle bearings may be interposed between the outer peripheral surface of the cylindrical support portion 50 and the inner peripheral surface of the recessed portion 41.

  In this way, the left lead groove 44 on the outer peripheral surface of the shift drum 40 rotatably mounted on the left and right crankcases 2L and 2R has the shift pin 33p of the shift fork 33 supported by the front shift fork shaft 31 and the rear. Two shift pins 33p and 34p of the shift pin 34p of the shift fork 34 supported by the side shift fork shaft 32 are slidably engaged, and the right lead groove 45 on the outer peripheral surface of the shift drum 40 has a rear side. A shift pin 35p of the shift fork 35 supported by the shift fork shaft 32 is slidably engaged.

6 is a developed view of the shift drum 40. Two shift pins 33p and 34p are engaged with one lead groove 44, and one shift pin 35p is engaged with another lead groove 45. FIG. .
In FIG. 6, the shift pins 33p, 34p, and 35p indicated by solid lines indicate the neutral state, and the two-dot chain line indicates the positions from the first to fifth speeds (the shift speed is indicated in parentheses in the reference numerals of the shift pins). In order to distinguish between the shift pins 33p and 34p engaged with the same lead groove 44, the shift pin 34p is a double circle.

The transmission mechanism 20 shown in FIG. 4 shows a neutral state, and in this neutral state, shift pins 33p, 34p, and 35p are located at neutral positions indicated by solid lines in FIG.
Referring to FIGS. 4 and 6, when shift drum 40 is rotated one step from the neutral state to the first speed side, only shift pin 35p moves to the right side, so shift fork 35 is a fifth speed gear on counter shaft 23. n5 is moved to the right and engaged with the first gear n1 to establish the first gear.

When the shift drum 40 rotates in the reverse direction from the first speed and returns to the neutral position and further rotates one step toward the second speed side, only the shift pin 34p moves to the left from the neutral position, so that the shift fork 34 is mounted on the counter shaft 23. The second gear n2 is moved to the left and engaged with the second gear n2 to establish the second gear.
When the shift drum 40 rotates by one step from the second speed to the third speed side, the shift pin 34p returns to the neutral position and the shift pin 35p moves to the left side. The third gear is established by engaging with the gear n3.

When the shift drum 40 rotates from the third speed to the fourth speed side by one step, the shift pin 35p returns to the neutral position and the shift pin 33p moves to the left side, so the shift fork 33 moves the third speed gear m3 on the main shaft 21 to the left side. To establish the fourth speed by engaging with the fourth speed gear m4.
Further, when the shift drum 40 rotates one step from the fourth speed to the fourth speed side, only the shift pin 33p moves to the right and passes further to the right after the neutral position, so that the shift fork 33 is moved to the third speed gear m3. Is moved to the right and engaged with the fifth gear m5 to establish the fifth gear.
Although the shift-up process of the gear stage has been described above, the shift-down is performed by driving in the opposite manner.

  In this speed change drive mechanism 30, two shift forks 33, 34 are engaged with one lead groove 44 of the shift drum 40. The two lead grooves 44 and 45 are sufficient to secure the number of shift stages, and three lead grooves are not required. Therefore, the shift drum 40 can reduce the width in the left-right axial direction, and the crankcase 2 can be downsized. be able to.

A rotation angle detector 55, which is a rotation detector, is fitted and held on the inner peripheral surface of the cylindrical support portion 50 inserted into the recessed portion 41 of the shift drum 40.
As shown in FIG. 7, the rotation angle detector 55 has a rotation operation shaft 56 protruding rightward so as to face the connection protrusion 43 protruding into the left recessed portion 41 of the shift drum 40. An engaging pin 57 projects from 56 in the radial direction.

  In this rotation angle detector 55, about half of the cylindrical main body is accommodated in the recessed portion 41 of the shift drum 40, and the rotation operation shaft 56 protruding rightward of the rotation angle detector 55 is a connecting projection 43 of the shift drum 40. The engaging pin 57, which is inserted into the cylindrical opening of the rotating projection shaft 56 in the radial direction and engages with the cut groove 43v of the connecting projection 43, and the rotating operation shaft 56 and the connecting projection 43 are connected coaxially. Is done.

  Accordingly, the rotation angle detector 55 fixedly supported by the cylindrical support portion 50 of the left crankcase 2L can detect the rotation angle of the shift drum 40 by the connection between the rotation operation shaft 56 and the connection protrusion 43.

  Since the rotation angle detector 55 is about half of the main body within the recessed portion 41 of the shift drum 40, it is possible to reduce the occupied space in the left and right axis direction and to equip the shift drum 40 with the rotation angle detector 55 in a compact manner. Therefore, the crankcase 2 that supports the shift drum 40 and the rotation angle detector 55 can be downsized without being enlarged for the rotation angle detector 55, and thus the internal combustion engine 1 can be downsized.

  A cylindrical support portion 50 protruding from the left crankcase 2L is inserted into the recessed portion 41 of the shift drum 40, and the shift drum 40 is rotatably supported on the outer peripheral surface of the cylindrical support portion 41 and rotated on the inner peripheral surface. Since the angle detector 55 is fitted and held, the rotation angle detector 55 has a simple structure with a small number of parts that does not have a dedicated part for supporting the rotation angle detector 55 using the cylindrical support portion 50 in common. The shift drum 40 can be compactly equipped, and the crankcase 2 and the internal combustion engine 1 can be reduced in size and weight.

  Since the rotation operation shaft 56 of the rotation angle detector 55 is connected to the rotation connection portion 43 formed on the rotation center axis in the recessed portion 41 of the shift drum 40, the rotation operation shaft 56 and the rotation connection portion 43 are connected. The portion is in the recessed portion 41 of the shift drum 40 to be protected.

The bolt boss portion 42 pivotally supported by the bearing 52 of the shift drum 40 is provided with a drum center 61, which is a speed change feed member of a pole ratchet mechanism 60, which is a speed change intermittent feed mechanism, by a deformed bolt 62 screwed into the bolt hole 42b. Coaxially connected and protrudes to the right.
Note that a key 70 that fixes the positions of the shift drum 40 and the drum center 61 in the rotational direction is engaged with both.

  In the shift drum 40, a drum center 61, which is a speed change feed member of the pole ratchet mechanism 60, is fixed on the rotation center axis by a deformation bolt 62, and a rotation angle detector 55 is connected to a rotation connecting portion 43 protruding on the rotation center axis. Since the rotation operation shaft 56 is coaxially connected, the rotation portions of the drum center 61, the shift drum 40, and the rotation angle detector 55 are on the same rotation center axis, and are detected by the rotation angle detector 55 with a simple configuration. Accuracy can be improved.

The deformation bolt 62 has a central shaft portion 62b protruding from the head portion 62a as a bolt on the opposite side of the screw portion.
In the ratchet housing 61h of the drum center 61, a shifter 64 that holds the ratchet pole 63 so as to be freely retractable is rotatably supported on the central shaft portion 62b of the deformation bolt 62, and the pole ratchet mechanism 60 is configured. ing.

  A plurality of engagement grooves are formed on the outer peripheral surface of the drum center 61, and a locking roller 71 r at the tip of the swinging drum stopper arm 71 urged by the spring 72 is fitted into one engagement groove of the drum center 61. The drum center 61 is stably positioned together with the shift drum 40.

On the other hand, a shift spindle 65 is installed below the rear shift fork shaft 32 so as to penetrate the left and right crankcases 2L and 2R, and a foot shift lever 66 is attached to the left end of the shift spindle 65. A shift arm 67 is provided at the right end of the shift spindle 65 by fitting the base end portion thereof, and protrudes to the right of the shifter 64 in a long hole 67a formed at the swinging tip of the shift arm 67. The protrusion 64a is engaged.
The shift arm 67 is urged in one direction by a return spring 68.

  Therefore, when the shift arm 67 swings integrally by the rotation of the shift spindle 65 by the operation of the foot shift lever 66, the shifter 64 is rotated by the engagement of the long hole 67a and the protrusion 64a, and the shifter 64 is rotated. The drum center 61 is intermittently rotated via the pole ratchet mechanism 60, and the shift drum 40 integrated with the drum center 61 is rotated.

As described above, the rotation of the two lead grooves 44 and 45 on the outer peripheral surface of the shift drum 40 guides the shift forks 33, 34 and 35 and moves in the axial direction so that the speed change mechanism 20 becomes effective. Select the gear combination and set the number of gears.
The rotation angle detector 55 can detect the rotation angle of the shift drum 40 that sets the number of shift stages of the transmission mechanism 20.

Instead of the rotation angle detector 55, a neutral detector may be attached as an axial movement device, and another embodiment in which a neutral detector 80 is attached is shown in FIG.
In FIG. 8, except for the neutral detector 80 and the connecting projection 82, it is almost the same as that of the embodiment shown in FIG.
In the present embodiment, the shaft support by the cylindrical support portion 50 of the shift drum 40 is supported by the needle bearing 85 interposed between the outer peripheral surface of the cylindrical support portion 50 and the inner peripheral surface of the recessed portion 41. Has been made.

The neutral detector 80 is an on / off detector that is turned on when the operating shaft 81 protrudes freely so that it can be retracted and retracted by a predetermined amount.
In the neutral detector 80, about half of the cylindrical body is accommodated in the recessed portion 41 of the shift drum 40 and fixedly supported by the cylindrical support portion 50 of the left crankcase 2L. It is more eccentric and fixed to the cylindrical support part 50.

  The tip end surface 82a of the cylindrical connecting projection 82 protruding into the recessed portion 41 of the shift drum 40 is formed with a surface perpendicular to the axial direction and an inclined surface that extends smoothly to the left, and is neutrally detected. The eccentric operating shaft 81 of the vessel 80 is in contact with the tip surface 82a.

Therefore, when the shift drum 40 is rotated, the operating shaft 81 of the neutral detector 80 that is in contact with the front end surface 82a of the connecting protrusion 82 slides on the inclined surface and moves in the axial direction.
When the shift drum 40 is at the neutral rotation angle, the neutral detector 80 is set so that the operating shaft 81 is retracted by a predetermined amount and turned on.

  As for the neutral detector 80, about half of the main body can be accommodated in the recessed portion 41 of the shift drum 40, the space occupied in the left-right axis direction can be reduced, and the neutral detector 80 can be compactly equipped on the shift drum 40. The crankcase 2 can be downsized, and thus the internal combustion engine 1 can be downsized.

In the above embodiment, the shift drum is rotated by manual operation to change the gear stage. However, the embodiment shown in FIG. 9 is an automatic operation in which the gear stage is changed by a servo motor 90 which is a rotary drive machine. A transmission mechanism.
The servo motor 90 is attached to the place where the rotation angle detector 55 of the embodiment shown in FIG. 5 is attached.

9, except for the servo motor 90, it is almost the same as the embodiment shown in FIG. 5, and the same reference numerals are used for the same members or corresponding members.
In addition, since the speed change drive is performed by the servo motor 90, there is no foot shift lever or a pole ratchet mechanism.

  In the servo motor 90, about half of the cylindrical body is accommodated in the recessed portion 41 of the shift drum 40, and the drive shaft 91 protruding to the right of the servo motor 90 is inserted into the cylindrical opening of the connecting projection 43 of the shift drum 40. Thus, the engaging pin 92 protruding in the radial direction on the drive shaft 91 engages with the cut groove 43v of the connecting protrusion 43, and the driving shaft 91 and the connecting protrusion 43 are connected coaxially.

  Therefore, when the servo motor 90 is driven and the drive shaft 91 is rotated, the shift drum 40 is directly rotated through the engagement of the engagement pin 92 and the cut groove 43v of the connecting projection 43, and the shift stage is changed. Made.

  Since the servo motor 90 is about half of the main body within the recessed portion 41 of the shift drum 40, the space occupied in the left-right axis direction can be reduced and the servo motor 90 can be compactly equipped on the shift drum 40. The crankcase 2 that supports 90 can be downsized, and thus the internal combustion engine 1 can be downsized.

1 is a schematic left side view in which a part of an internal combustion engine according to an embodiment of the present invention is omitted and partly cross-sectional. It is the same schematic right view. It is the III-III sectional view taken on the line of FIG. FIG. 4 is an enlarged view of the speed change mechanism of FIG. 3. It is the VV sectional view taken on the line of FIG. It is an expanded view of a shift drum. It is a perspective view which shows the engaging part of the rotation protrusion of a rotation angle detector, and the connection protrusion of a shift drum. It is principal part sectional drawing of another embodiment. Moreover, it is principal part sectional drawing of another embodiment.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 ... Internal combustion engine, 2L ... Left crankcase, 2R ... Right crankcase,
30 ... shift drive mechanism, 31, 32 ... shift fork shaft, 33,34,35 ... shift fork,
40 ... shift drum, 41 ... concave portion, 42 ... bolt boss portion, 42b ... bolt hole, 43 ... connecting projection, 44,45 ... lead groove, 55 ... rotation angle detector, 56 ... rotation operating shaft, 57 ... engagement pin , 60 ... Paul ratchet mechanism, 61 ... Drum center.
80 ... Neutral detector,
90: Servo motor.

Claims (8)

In the mounting structure of the axial movement device in which the axial movement device in which the fixed portion holds the shaft portion that engages and interlocks with the rotating member that is rotatably supported by the case is fixed to the case,
A recess is formed on at least one end surface of the rotating member in the rotation axis direction,
The mounting structure for an axial motion device, wherein the axial motion device is disposed inside a recessed portion of the rotating member. A cylindrical support portion protruding from the case is inserted into the recessed portion of the rotating member, and the rotating member is rotatably supported by the outer peripheral surface of the cylindrical support portion,
2. The mounting structure for an axial motion device according to claim 1, wherein a fixed portion of the axial motion device is fitted and held on an inner peripheral surface of the cylindrical support portion.   3. The axial movement device according to claim 1, wherein a shaft portion of the axial movement device is engaged with a rotation connecting portion formed on a rotation center axis in the recessed portion of the rotation member. Mounting structure.   4. The structure for mounting an axial movement device according to any one of claims 1 to 3, wherein the rotating member is a shift drum of a transmission.   5. The structure for mounting an axial movement device according to claim 4, wherein at least two shift forks are engaged with one lead groove formed on the outer peripheral surface of the shift drum. A bolt hole is formed on the rotation center axis of the end opposite to the recessed portion of the shift drum,
A shift feed member of a shift intermittent feed mechanism is fixed to the shift drum by a bolt screwed into the bolt hole,
6. The mounting structure for an axially moving device according to claim 4, wherein the rotation connecting portion protrudes on a rotation center shaft, and the shaft portion is engaged with the rotation connecting portion.   The said axially-moving device is a rotation detector which detects the rotation state of the said rotation member, The attachment structure of the axially-moving device of any one of Claim 1-6 characterized by the above-mentioned.   6. The mounting structure for an axial motion device according to claim 1, wherein the axial motion device is a rotary drive device that rotates the rotating member. 7.

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