JP2009029253A - Breather structure of deceleration chamber of power unit - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a breather structure of a deceleration chamber of a power unit positioning a breather pipe extended from the deceleration chamber by a simple structure to easily perform a mounting work of the breather pipe. <P>SOLUTION: In this power unit 20, the deceleration chamber 110C is constituted by covering a rear part of a transmission case 23 with a deceleration device cover 25 to cover a deceleration device 110. The breather pipe 171 extended to the outside upward from the deceleration chamber 110C is bent to the transmission case 23 side and is extended along an upper surface of the transmission case 23 and an upper surface of a transmission case cover 24. The distal end opening faces to an opening supporting part 27p provided in an internal surface of a side cover 27 covering a further outside surface of the transmission case cover 24. A projected line 23T is projected and formed to be directed in a longitudinal direction on the upper surface of the transmission case 23. The breather pipe 171 is positioned by being fitted to a cut-out 23v formed in the projected line 23T. <P>COPYRIGHT: (C)2009,JPO&INPIT

Description

  The present invention relates to a breather structure of a deceleration chamber of a power unit that is swingably provided in a motorcycle.

In a swing type power unit that is swingably provided in a motorcycle, the power transmitted to the rear part of the power unit by the transmission mechanism is transmitted to the rear wheel via the speed reduction mechanism.
A rear part of the power unit is formed with a speed reduction chamber for accommodating the speed reduction mechanism in a partition with a power transmission room for accommodating the power transmission mechanism.

  Various proposals have been made for the breather structure of the deceleration chamber. In each case, the tip opening is located in a hole provided at a location suitable for the breather pipe extending from the deceleration chamber to extend through the transmission chamber and communicate with the outside. (For example, refer to Patent Document 1).

JP 2001-355424 A

  In the power unit disclosed in Patent Document 1, the breather pipe that extends from the deceleration chamber into the transmission chamber is guided by a guide groove formed on the inner surface of the transmission case and faces the left cover (inner cover) of the transmission case. The tip opening faces the circular hole drilled in the left cover.

  Therefore, the breather pipe must be piped along the inner surface of the transmission case, and the tip opening of the breather pipe that protrudes from the inside of the transmission case when the left cover is assembled to the transmission case is formed in the left cover. Since it is necessary to face the hole, the work of installing the breather pipe is not easy and troublesome.

  The present invention has been made in view of the above points, and the object of the present invention is to position the breather pipe extending from the deceleration chamber with a simple structure and to install the breather pipe easily. The point is to provide a breather structure.

  In order to achieve the above object, an invention according to claim 1 is a power unit swingably provided in a motorcycle, and is a part of a transmission case that also serves as a crankcase that rotatably supports a crankshaft of an internal combustion engine. A belt-type continuously variable transmission is provided on the side, and a transmission case cover covers the transmission case from one side so as to cover the belt-type continuously variable transmission to form a transmission chamber, and the rear part of the transmission case In a power unit that is provided with a reduction gear on the other side and a reduction gear cover is placed on the rear part of the transmission case from the other side so as to cover the reduction gear, and constitutes a reduction chamber. The breather pipe extending to the transmission case is bent toward the transmission case side and extends along the upper surface of the transmission case and the upper surface of the transmission case cover, and the tip opening thereof is the transmission case cover. Facing the opening support provided on the inner surface of the side cover that covers the outer surface of the side, and a protrusion is formed on the upper surface of the transmission case in the front-rear direction, and the notch formed in the protrusion The breather structure of the deceleration chamber of the power unit in which the breather pipe is fitted and positioned.

  According to a second aspect of the present invention, in the breather structure of the speed reduction chamber of the power unit according to the first aspect, a protective cover covering from the side to the upper side of the speed reducer cover covers a bent portion of the breather pipe, An upper wall that covers an upper surface of the transmission case cover extends toward the transmission case and covers the breather pipe from above.

  According to a third aspect of the present invention, in the breather structure of the deceleration chamber of the power unit according to the first or second aspect, the ridge on the upper surface of the transmission case extends to a front crankcase equivalent portion, and the transmission The wiring of the auxiliary machines attached to the case is supported by the protrusions.

  According to a fourth aspect of the present invention, in the breather structure of the power unit deceleration chamber according to any one of the first to third aspects, the wiring of the auxiliary equipment attached to the transmission case is connected to the side cover. It is characterized by being sandwiched between an opening support provided on the inner surface and supporting the breather pipe and the transmission case cover.

  According to the breather structure of the speed reduction chamber of the power unit according to claim 1, since the breather pipe extends outward from the speed reduction chamber, it is easy to handle the breather pipe and is directed to the upper surface of the transmission case in the front-rear direction. It is easy to fit and position the breather pipe in the protruding notch of the protruding ridge, and at the time of assembly of the side cover, the opening support part provided on the inner surface of the side cover opens the tip of the breather pipe It is also possible to make it easier to install the breather pipe.

According to the breather structure of the speed reducer chamber of the power unit according to claim 2, the protective cover that covers from the side of the speed reducer cover to the upper side covers the bent portion of the breather pipe, so that the bent portion of the breather pipe is pressed and fixed. Thus, it is possible to prevent the breather pipe from being pushed and deformed when the side cover is assembled, and to protect the bent portion of the breather pipe with the protective cover.
And since the upper wall which covers the upper surface of the transmission case cover of the side cover extends to the transmission case side and covers the breather pipe from above, the breather pipe is entirely covered and protected by the protective cover and the side cover, The breather pipe is not visible from the outside and can maintain a good appearance.

According to the breather structure of the deceleration chamber of the power unit according to claim 3, the protrusion on the upper surface of the transmission case extends to a portion corresponding to the crankcase on the front side. It is possible to prevent water, mud and other foreign matters from entering between the cover and the cover.
Since the wiring of the auxiliary machine attached to the transmission case is supported by the ridge, the ridge has three functions of preventing entry of foreign matter, positioning of the breather pipe, and supporting the wiring of the auxiliary machine. The number of parts can be reduced and the structure can be simplified.
Here, the auxiliary machines include various detection sensors.

  According to the breather structure of the deceleration chamber of the power unit according to claim 4, the wiring of the auxiliary machine attached to the transmission case is provided on the inner surface of the side cover and between the opening support portion that supports the breather pipe and the transmission case cover. Therefore, the opening support portion on the inner surface of the side cover can be used for positioning the wiring of the auxiliary machine.

An embodiment according to the present invention will be described below with reference to FIGS.
FIG. 1 is a side view of a scooter type motorcycle 1 equipped with a power unit 20 according to an embodiment to which the present invention is applied.
The vehicle body front portion 2 and the vehicle body rear portion 3 are connected via a low floor portion 4, and the vehicle body frame forming the skeleton of the vehicle body is generally composed of a down tube 6 and a main pipe 7.

  That is, the down tube 6 extends downward from the head pipe 5 at the vehicle body front portion 2, the down tube 6 is bent horizontally at the lower end and extends rearward below the floor portion 4, and a pair of left and right main pipes 7 at the rear end. The main pipe 7 rises diagonally rearward from the connecting portion, bends horizontally at a predetermined height, and extends rearward.

A fuel tank and a storage box are supported by the main pipe 7, and a seat 8 is disposed above the fuel tank and the storage box.
On the other hand, in the front part 2 of the vehicle body, a handle 11 is provided above and supported by the head pipe 5, and a front fork 12 extends downward and a front wheel 13 is supported at the lower end thereof.

  A bracket 15 protrudes in the vicinity of the center of the obliquely inclined portion of the main pipe 7, and the power unit 20 is connected and supported in a swingable manner via a link member 16 pivotally supported by the bracket 15.

  The power unit 20 includes an internal combustion engine 30 at a front portion of a unit case 21, a belt-type continuously variable transmission 50 is disposed from the internal combustion engine 30 to the rear, and a reduction gear mechanism 110 is integrally provided at a rear portion thereof. The output shaft of the reduction gear mechanism 110 is the rear axle 114, and the rear wheel 17 is attached (see FIG. 2).

  The power unit 20 has a pair of left and right power unit hangers 21h and 21h projecting forward at the front upper portion of the unit case 21 and connected to the lower end of the link member 16 via a pivot shaft 19. On the other hand, a rear cushion 18 is interposed between the bracket 29 at the rear end of the unit case 21 (transmission case 23) and the main pipe 7 at the rear part capable of swinging (see FIG. 1).

  The internal combustion engine 30 is a single-cylinder four-stroke cycle internal combustion engine that protrudes from the front surface of the unit case 21 with the cylinder block 31, the cylinder head 32, and the cylinder head cover 33 stacked substantially forward to a nearly horizontal state. ing.

A throttle body 34b is connected to an intake pipe 34a extending upward from the intake port on the upper side of the cylinder head 32 and bent rearward, and a connecting pipe 34c extending rearward from the throttle body 34b is connected to the rear half of the unit case 21. It is connected to an air cleaner 34d arranged along the left side of the wheel 17.
Further, an exhaust pipe 35 extending downward from the lower exhaust port of the cylinder head 32 and bent rearward is biased to the right and extends rearward and is connected to a muffler (not shown) on the right side of the rear wheel 17.

The vehicle body front part 2 is covered from the front and rear by a front cover 9a and a rear cover 9b, and from the left and right sides by a front lower cover 9c, and the center part of the handle 11 is covered by a handle cover 9d.
The floor portion 4 is covered with a side cover 9e, and the vehicle body rear portion 3 is covered with a body cover 10a and a tail side cover 10b from the left and right sides.

2 is an external left side view of the power unit 20, and FIG. 3 is a left side view of the power unit 20 with the front side cover 26 and the rear side cover 27 serving as the left exterior cover removed, and FIG. 5 is a left side view with the transmission case cover 24 removed, and FIG. 5 is a right side view with the power unit 20 partially omitted and the reduction gear cover 25 removed.
6 is a sectional view taken along the line VI-VI in FIG. 2 and developed, and FIG. 7 is a partially enlarged view of FIG.

Referring mainly to FIG. 6, the unit case 21 is divided into left and right parts, and the left unit case extends rearward with respect to the right unit case 22 to constitute a transmission case 23.
The transmission case 23 includes a left crankcase portion 23a formed on the front right side, a transmission case portion 23b formed on the left side from the front portion to the rear portion, and a reduction gear portion 23c formed on the rear right side. The left crankcase portion 23a is combined with the right unit case 22 to form a crank chamber 40C that accommodates the crankshaft 40, and the transmission case portion 23b is covered with the transmission case cover 24 from the left side so as to be a belt type continuously variable transmission 50. And a rear reduction gear portion 23c is covered with the reduction gear cover 25 to constitute a reduction gear chamber 110C for accommodating the reduction gear mechanism 110.

  In the crank chamber 40C, a cylinder sleeve 31s formed in the cylinder block 31 protrudes into the crank chamber 40C, and the reciprocating motion of the piston 36 slidably fitted in the cylinder sleeve 31s causes the connecting rod 37 to move. Through the unit case 21 is transmitted to the crankshaft 40 that is rotatably supported in the horizontal direction, and the crankshaft 40 is rotated.

An intake rocker arm 38bi and an exhaust rocker arm 38be are slidably in contact with a camshaft 38a of a valve mechanism 38 provided in a cylinder head 32 inclined forward to near horizontal, and an intake valve and an exhaust gas (not shown) are exhausted by the intake rocker arm 38bi and the exhaust rocker arm 38be. The valve is driven to open and close. The camshaft 38a has a reduction ratio of 1/2 that of the crankshaft 40 by a timing chain 38e spanned between a driven sprocket 38c fitted to the right end of the camshaft 38a and a drive sprocket 38d fitted to the crankshaft 40. Is rotated.
In addition, an ignition plug 39p is attached to the cylinder head 32 by exposing an electrode to a combustion chamber 39 defined by a ceiling surface facing the top surface of the piston 36.

In the crank chamber 40C, the crankshaft 40 is rotatably supported in the left and right bearing circular holes of the unit case 21 via main bearings 41 and 41, and a pair of left and right crank webs 40w and 40w are accommodated in the left and right horizontal directions. An AC generator 42 is provided in the right extension portion of the extended portion, and a drive pulley 51 of the belt type continuously variable transmission 50 is provided in the left extension portion together with the speed change drive mechanism 60.
The AC generator 43 is covered with a generator cover 28 from the right side.

With reference to FIG. 7, the left end of the crankshaft 40 is pivotally supported via a bearing 43 on an annular bearing portion 24 </ b> Fa of the transmission case cover 24 via a collar 54.
The drive pulley 51 includes a fixed pulley half 51s and a movable pulley half 51d.

  A bearing 52, a guide sleeve 53, a fixed pulley half 51s, and the collar 54 are fitted in this order from the right to the left extending portion from the step portion 40a that is reduced in diameter to the crankshaft 40, and the left end of the crankshaft 40 is fitted. The inner ring of the bearing 52, the guide sleeve 53, the base of the fixed pulley half 51s, and the collar 54 are fastened to the surface by a bolt 56 through a washer 55, and are integrated with the crankshaft 40.

Accordingly, the fixed pulley half 51 s is sandwiched between the guide sleeve 53 and the collar 54 and is fixed integrally with the crankshaft 40, and rotates integrally with the crankshaft 40.
A cooling fan 51F protrudes from the back surface (left side surface) of the fixed pulley half 51s.

  On the other hand, the movable pulley half 51d facing the fixed pulley half 51s on the right side is rotated simultaneously with the crankshaft 40 while the cylindrical movable pulley hub 51dh, which is the base thereof, is partially spline-fitted to the guide sleeve 53. It is slidable in the direction.

  Thus, the right movable pulley half 51d facing the left fixed pulley half 51s rotates together with the crankshaft 40 and slides in the axial direction so as to approach and separate from the fixed pulley half 51s. The V belt 58 is sandwiched and wound between the tapered surfaces of the pulley halves 51s and 51d facing each other.

  Referring to FIGS. 4 and 6, the transmission case 23 has a rear portion larger than the power unit hanger 21h in the transmission case portion 23b formed on the left side with respect to the left crankcase portion 23a formed on the front right side. A shift electric motor 61 that is a drive source of the shift drive mechanism 60 is attached to the upper portion of the bulge portion 23e from the right side.

  A gear cover member (not shown) is partially attached to the bulging portion 23e of the transmission case 23 from the left side, and the first reduction gear shaft 63s and the second reduction gear are provided between the gear cover member and the wall surface of the transmission case 23. A gear shaft 65s is rotatably supported, and a drive gear 61a formed on the drive shaft 61s of the speed change electric motor 61 meshes with the large-diameter gear 63a of the first reduction gear shaft 63s, and the first reduction gear. The small diameter gear 63b of the shaft 63s is meshed with the large diameter gear 65a of the second reduction gear shaft 65s (see FIG. 4).

On the other hand, a female screw member 67 is fixed by a bolt 68 to a disc boss member 66 whose base end portion is supported by an outer ring of a bearing 52 fitted to the crankshaft 40, and has a large diameter at a flange portion of the female screw member 67. A gear 67a is formed, and the large diameter gear 67a meshes with the small diameter gear 65b of the second reduction gear shaft 65s.
A female screw (screw screw) is formed on the inner peripheral surface of the cylindrical portion 67 s of the female screw member 67.

A male screw member 70 is supported via a bearing 69 that is fitted to the outer periphery of a movable pulley hub 51dh that supports the movable pulley half 51d and is slidable in the axial direction. A cylindrical portion 70s of the male screw member 70 is formed by a female screw. Inside the cylindrical portion 67s of the member 67, a male screw formed on the outer peripheral surface of the cylindrical portion 70s is screwed with a female screw on the inner peripheral surface of the cylindrical portion 67s.
In the male screw member 70, the left end of the cylindrical portion 70s is exposed to the left from the left opening end of the cylindrical portion 67s of the female screw member 67, and the flange portion 70a extends in the centrifugal direction along the back surface of the movable pulley half 51d from the left end. It extends to.

  An annular member 71 is fixed to the outer peripheral portion of the flange portion 70a of the male screw member 70, and the rear portion of the annular member 71 extends rearward and extends rightward in the axial direction so as to wrap around the outside of the large-diameter gear 67a of the female screw member 67. The pair of upper and lower guide pieces 72, 72 projecting into the transmission chamber 50C of the transmission case 23 regulates the rotation of the extension portion 71a and guides the movement in the axial direction. (See FIG. 7).

  Therefore, the male screw member 70 supported by the movable pulley hub 51dh integral with the movable pulley half 51d via the bearing 69 is restricted in rotation by the guide pieces 72, 72 and can slide only in the axial direction.

  The speed change drive mechanism 60 is configured as described above, and when the speed change electric motor 61 is driven and the drive gear 61a formed on the drive shaft 61s rotates, the first reduction gear shaft 63s meshes with the drive gear 61a. The large-diameter gear 63a rotates at a reduced speed together with the small-diameter gear 63b, and the large-diameter gear 65a of the second reduction gear shaft 65s that meshes with the small-diameter gear 63b further rotates at a reduced speed together with the small-diameter gear 65b. The large-diameter gear 67a of the member 67 further rotates at a reduced speed, and the female screw member 67 rotates.

When the female screw member 67 rotates, the male screw member 70 screwed with the female screw member 67 is restricted from rotating, so that it moves in the axial direction by the screw mechanism.
To move the male screw member 70 in the axial direction, the movable pulley hub 51dh is moved in the axial direction integrally with the movable pulley half 51d via the bearing 69, and the movable pulley half 51d is moved toward and away from the fixed pulley half 51s. Can do.

  The movable pulley half 51d is moved in the axial direction while rotating together with the crankshaft 40 because the movable pulley hub 51dh that integrally supports the movable pulley half 51d is spline-fitted to the guide sleeve 53 integral with the crankshaft 40. become.

  In this way, the movable pulley half 51d approaches and separates from the fixed pulley half 51s by forward / reverse driving of the speed change electric motor 61, so that the pulleys 51s and 51d are wound between the opposing tapered surfaces. The winding diameter of the V-belt 58 is changed to perform continuously variable transmission.

A starter motor 75 is attached to the right crankcase 22 and disposed obliquely below and behind the speed change electric motor 61 attached to the bulging portion 23e of the transmission case portion 23b from the right side.
The starter motor 75 has a posture in which the drive shaft 75s is parallel to the left-right direction in the same manner as the electric motor 61 for speed change, and from the left side to the left side surface of the bulging portion 22e that bulges to the right of the right crankcase 22 It is attached (see FIG. 5).

Referring to FIG. 5 which is a right side view, a reduction gear shaft 76s is rotatably supported between the drive shaft 75s of the starter motor 75 and the crankshaft 40, and a large-diameter gear integrated with the reduction gear shaft 76s. 76a meshes with a drive gear 75a formed on the drive shaft 75s.
On the other hand, a driven gear 77 is fitted and supported on a rotating boss 78 rotatably supported by the crankshaft 40 adjacent to the AC generator 42 provided at the right end of the crankshaft 40 (see FIG. 6). A driven gear 77 meshes with a small diameter gear 76b integrated with the reduction gear shaft 76s.

A one-way clutch 79 is interposed between the outer rotor 42r integral with the crankshaft 40 of the AC generator 42 and the rotating boss 78.
Therefore, when the starter motor 75 is driven and the drive gear 75a formed on the drive shaft 75s rotates, the large-diameter gear 76a of the reduction gear shaft 76s that meshes with the drive gear 75a rotates at a reduced speed together with the small-diameter gear 76b. The driven gear 77 meshing with 76b further rotates at a reduced speed together with the rotating boss 78, and the rotation of the rotating boss 78 rotates the outer rotor 42r of the AC generator 42 together with the crankshaft 40 via the one-way clutch 79, thereby starting the internal combustion engine 30. It can be performed.

5, the balancer shaft 105 is pivotally supported above the crankshaft 40 so that the balancer weight 105w rotates between the left and right crank webs 40w, 40w, and the balancer is fitted to the balancer shaft 105. A driven gear 104 meshes with a balancer drive gear 103 fitted on the crankshaft 40.
Therefore, the vibration associated with the operation of the internal combustion engine 30 is suppressed by the balancer weight 105w that rotates in synchronization with the rotation of the crankshaft 40.

Next, the structure of the rear part of the power unit 20 will be described.
Referring to FIG. 6, driven pulley 81 corresponding to drive pulley 51 of belt-type continuously variable transmission 50 is composed of a fixed pulley half 81s and a movable pulley half 81d. It is supported by.
The driven shaft 82 is rotatably supported by bearings 83, 84, and 85 at three locations of the transmission case 23, the transmission case cover 24, and the reduction gear cover 25, respectively.

  Referring to FIG. 6, the left side portion of the driven shaft 82 is formed with a small diameter portion 82a whose outer diameter is slightly reduced from the stepped portion, and a bearing 86, a support sleeve 87, and a collar 88 are fitted in this small diameter portion 82a in this order. The nut 89 is screwed onto the end and fastened together.

The bearing 84 is interposed between the annular bearing portion 24Ra of the transmission case cover 24 and the collar 88.
A base portion of a clutch outer 91 having a hook shape of the centrifugal clutch 90 is fixed to the support sleeve 87 so as to rotate integrally with the driven shaft 82.

  A cylindrical fixed pulley hub 95 that supports the fixed pulley half 81 s is driven by the bearing 86 and the bearing 96 on the outer periphery of the portion of the driven shaft 82 covered by the transmission case cover 24 on the right side of the clutch outer 91. The shaft 82 is rotatably supported relative to the shaft 82.

A support plate 92 a that is a clutch inner 92 of the centrifugal clutch 90 is fixed to the left end of the fixed pulley hub 95 by a nut 97.
An arm 92c is pivotally supported by a pivot 92b on the support plate 92a, and a clutch shoe 92d is secured to the tip of the arm 92c.
The arm 92c is biased by a spring 92e in a direction in which the clutch shoe 92d is separated from the inner peripheral surface of the clutch outer 91.

On the outer periphery of a cylindrical fixed pulley hub 95 that supports the clutch inner 92, a cylindrical movable pulley hub 98 that supports the movable pulley half 81d is provided slidably in the axial direction.
That is, a long guide hole 98a in the axial direction is formed in the cylindrical movable pulley hub 98, and a guide pin 99 protruding from the fixed pulley hub 95 is slidably engaged with the guide hole 98a. Yes.

Therefore, the movable pulley hub 98 is regulated in relative rotation with the fixed pulley hub 95 by the guide pin 99 and can slide in the axial direction on the fixed pulley hub 95 while being guided by the guide hole 98a.
A coil spring 100 is interposed between a support plate 92a integrally attached to the fixed pulley hub 95 and the movable pulley hub 98, and the movable pulley hub 98 is urged to the right by the coil spring 100.

  Due to the above configuration, the movable pulley half 81d supported by the movable pulley hub 98 rotates together with the fixed pulley half 81s supported by the fixed pulley hub 95 and is slidable in the axial direction. Thus, the coil spring 100 is biased in a direction approaching the fixed pulley half 81s.

  The V belt 58 is wound between the opposing tapered surfaces of the fixed pulley half 81s and the movable pulley hub 98, and the winding diameter of the driven pulley 81 is inversely proportional to the winding diameter on the drive pulley 51 side. It fluctuates and a continuously variable transmission is executed.

  When the rotation of the drive pulley 51 exceeds a predetermined number of revolutions, the clutch shoe 92d of the clutch inner 92 of the centrifugal clutch 90 comes into contact with the inner peripheral surface of the clutch outer 91 and rotates integrally to transmit power to the driven shaft 82.

On the right side of the rear portion of the transmission case 23, a reduction gear chamber 110C that is covered with the reduction gear cover 25 and accommodates the reduction gear mechanism 110 is configured.
As shown in FIG. 4, both ends of the reduction gear shaft 112s are supported between the rear portion of the transmission case 23 and the reduction gear cover 25 facing each other via bearings 111, 111, and are integrated with the reduction gear shaft 112s. The large-diameter gear 112a meshes with a small-diameter gear 82g formed on the driven shaft 82.

  Similarly, a rear axle 114 is rotatably supported by the rear portion of the transmission case 23 and the reduction gear cover 25 via bearings 113, 113, and the rear axle 114 protrudes rightward from the right bearing 113, A large-diameter gear 114a fitted integrally with the rear axle 114 is engaged with a small-diameter gear 112b integral with the reduction gear shaft 112s.

A rear wheel 17 is fitted to a portion of the rear axle 114 that protrudes to the right from the reduction gear cover 25.
Accordingly, the rotation of the driven shaft 82 is decelerated via the reduction gear mechanism 110 and transmitted to the rear axle 114, whereby the rear wheel 17 is rotated.

  In the power transmission structure of the power unit 20 as described above, a configuration in which cooling air is introduced into the transmission chamber 50C formed by the transmission case 23 and the transmission case cover 24 to cool the belt type continuously variable transmission 50 is the transmission case cover 24. Is provided at the front.

FIG. 8 is a left side (outer side) view of the transmission case cover 24, FIG. 9 is a right side (inner side) view of the transmission case cover 24, and FIG. 10 is a sectional view taken along line XI-XI in FIG. As shown in FIG.
In FIG. 18 showing the substantially rear half of the power unit 20, a transmission case cover 24 is shown together with the transmission case 23 in a perspective view.

The transmission case cover 24 bulges from the mating surface 24s with the transmission case 23 to the left side (outside) in a substantially circular flat plate shape to form a circular wall portion 24F, and the latter half portion bulges into a large dome shape. The dome wall 24R is formed (see FIGS. 10 and 18).
The front circular wall portion 24F covers the drive pulley 51, and the rear dome wall 24R accommodates and covers the centrifugal clutch 90 so as to surround it.

  In the transmission case cover 24, a flat connecting wall 24C (see FIGS. 10 and 18) is formed between the circular wall portion 24F bulging outward and the dome wall 24R, and the front circular wall portion 24F. A bulging portion 24e is formed above the bulging portion 23 to face the bulging portion 23e of the transmission case 23.

  The annular bearing portion 24Fa for supporting the left end of the crankshaft 40 via the bearing 43 is formed at the central portion of the circular wall portion 24F, and the left end of the driven shaft 82 is supported via the bearing 84 for the apex portion of the dome wall 24R. The annular bearing portion 24Ra is formed.

The annular bearing portion 24Fa at the center of the circular wall portion 24F has an inner side wall bulging outward in the axial direction to form a small flange-shaped bulging wall 24Fb that covers the shaft end of the crankshaft 40. A small-diameter vent hole 24Fc is formed in the center of the exit wall 24Fb.
Similarly, the annular bearing portion 24Ra at the center of the dome wall 24R bulges inward in the axial direction to form a small ridge-like bulging wall 24Rb that covers the shaft end of the crankshaft 40, A small-diameter vent hole 24Rc is formed in the center of the bulging wall 24Rb.

Six fan-shaped cooling air inlets 24Fe are formed in the circular wall portion 24F on the outer periphery of the front annular bearing portion 24Fa, leaving six connecting ribs 24Fd formed radially.
That is, the annular bearing portion 24Fa is supported by the six connecting ribs 24Fd.
The cooling air introduction port 24Fe formed in the outer periphery of the annular bearing portion 24Fa is an opening for introducing the cooling air into the transmission chamber 50C.

Two of the six connecting ribs 24Fd are on a straight line connecting the front and rear vent holes 24Fc and 24Rc in a side view.
That is, the two front and rear connecting ribs 24Fd are formed on a plane S including the crankshaft 40 and the driven shaft 82 which are drive shafts of the belt type continuously variable transmission 50 (see FIG. 3).
Therefore, the rigidity in the front-rear direction of the transmission case cover 24 that receives force by the rotation of the V-belt 58 can be ensured, and vibration can be reduced.

An annular outer ring protrusion 24Ff and inner ring protrusion 24Fg slightly protrude to the left along the outer peripheral edge and inner peripheral edge of the six fan-shaped cooling air inlets 24Fe.
The outer ring protrusion 24Ff and the inner ring protrusion 24Fg are on the outer periphery of the bulging wall 24Fb.
Four holder mounting bosses 24Fh for mounting the filter holder 121 are formed on the outer periphery of the outer ring projection 24Ff.
Cover attachment bosses 24Fi are formed at a total of three locations, two at the front and rear, and one at the lower portion above the circular wall portion 24F.

On the other hand, on the outer dome wall 24R of the rear annular bearing portion 24Ra, three U-shaped outer ribs 24Rd extend radially from the central annular bearing portion 24Ra on the left side surface (outer surface). .
That is, each U-shaped outer rib 24Rd forms a U-shape in which a pair of substantially parallel sides extend in a centrifugal direction from the annular bearing portion 24Ra and both ends are curved and connected.
The three U-shaped outer ribs 24Rd are equally spaced from each other, and the base ends of adjacent U-shaped outer ribs 24Rd are connected to each other at the annular bearing portion 24Ra.

  Of these, one U-shaped outer rib 24Rd extends from the annular bearing portion 24Ra forward in parallel to a straight line connecting the front and rear vent holes 24Fc, 24Rc in a side view, and is formed at the tip curved portion that reaches the center of the transmission case cover 24. A cover mounting boss 24Rj for mounting the transmission case cover 24 to the transmission case 23 is formed (see FIG. 8).

A pair of sides of the U-shaped outer rib 24Rd extending forward is substantially in a plane S including the drive shaft (crankshaft 40) and the driven shaft 82 of the belt type continuously variable transmission 50 in the side view shown in FIG. They are formed in parallel and at approximately the same distance from the plane S.
Therefore, the rigidity in the front-rear direction of the dome wall 24R in the transmission case cover 24 is particularly high, and the vibration in the front-rear direction due to the rotation of the V-belt 58 of the belt type continuously variable transmission 50 can be more effectively suppressed.

The other two U-shaped outer ribs 24Rd extend in an angle direction of approximately 120 degrees obliquely rearward from the annular bearing portion 24Ra with respect to the U-shaped outer rib 24Rd extending in the front-rear direction. Each is provided with a cover mounting boss 24Re.
Therefore, the rigidity of the entire dome wall 24R can be efficiently increased with a small number of ribs.
A cover mounting boss 24Ri is formed at a lower portion of the connecting wall 24C.

Further, on the right side surface (inner side surface) of the dome wall 24R, six inner ribs 24Rf are formed radially from the central annular bearing portion 24Ra.
The six inner ribs 24Rf are formed at equal intervals around the annular bearing portion 24Ra, and the two inner ribs 24Rf extending in the front-rear direction are on a straight line connecting the front and rear vent holes 24Fc, 24Rc in a side view. is there.
Accordingly, three of the six inner ribs 24Rf are substantially parallel to the three outer U-shaped ribs 24Rd on the outer surface, and the inner ribs 24Rf are U-shaped outer ribs 24Rd in a side view shown in FIG. Between the U-shaped side ribs and do not overlap.

  As described above, the rear dome wall 24R of the transmission case cover 24 has three U-shaped outer ribs 24Rd projecting radially on the outer surface and six inner ribs 24Rf projecting radially on the inner surface. Therefore, since the rigidity of the dome wall 24R is remarkably high due to the synergistic effect of the U-shaped outer rib 24Rd and the inner rib 24Rf, vibration of the dome wall 24R can be suppressed with simple and few ribs.

  In addition, a cooling air derivation path 24y is formed in the lower part of the transmission case cover 24 at the center in the front-rear direction of the dome wall 24R, and a cooling air derivation path 24z is formed in the rear upper part.

FIG. 3 shows a state where the transmission case cover 24 as described above covers the belt-type continuously variable transmission 50 and covers the transmission case 23.
In the circular wall portion 24F on the front side of the transmission case cover 24, a hollow disk-shaped portion is formed in an annular portion in which six cooling air inlets 24Fe between the outer ring protrusion 24Ff and the inner ring protrusion 24Fg are formed. The filter element 120 is fitted and pressed from the outside by the filter holder 121, and the filter element 120 is attached to the cooling air inlet 24Fe.

  The filter holder 121 extends radially from the outer ring portion 121f, the inner ring portion 121g, and the inner ring portion 121g that are respectively fitted to the outer ring protrusion 24Ff and the inner ring protrusion 24Fg of the transmission case cover 24. It is generally formed from six connecting ribs 121d connected to the portion 121f, and extends in four radial directions from the outer ring portion 121f to form bolt boss portions 121h.

  The filter holder 121 has its six connecting ribs 121d opposed to the six connecting ribs 24Fd of the transmission case cover 24, and therefore corresponds to the six fan-shaped cooling air inlets 24Fe of the transmission case cover 24. A cooling air inlet 121e is formed.

  The filter holder 121 fits and connects the outer ring portion 121f and the inner ring portion 121g of the filter holder 121 to the outer ring protrusion 24Ff and the inner ring protrusion 24Fg of the transmission case cover 24, respectively. The six connecting ribs 24Fd of the filter holder 121 are pressed against the connecting ribs 24Fd so that the filter element 120 is sandwiched therebetween, and the bolt boss portions 121h are overlapped with the holder mounting bosses 24Fh at the four outer peripheries and fastened with the bolts 122. .

  Six cooling air inlets 121e of the filter holder 121 and the filter element 120 are arranged on the outer periphery of the bulging wall 24Fb bulged from the annular bearing portion 24Fa of the transmission case cover 24 so as to cover the shaft end of the crankshaft 40. The six cooling air inlets 24Fe of the transmission case cover 24 are formed around the outer periphery of the annular bearing portion 24Fa. The six cooling air inlets 24Fe are fixed pulley halfs fixed to the crankshaft 40. The rear surface of the body 51s is at a position facing the cooling fan 51F.

  Accordingly, the cooling air is passed through the cooling fan 51F rotating integrally with the crankshaft 40 from the outside of the filter holder 121 in the order of the cooling air introduction port 121e, the filter element 120, and the cooling air introduction port 24Fe, and is filtered into the transmission chamber 50C. be introduced.

The inner side wall of the annular bearing portion 24Fa that pivotally supports the end portion of the crankshaft 40 in the transmission case cover 24 via the bearing 43 bulges outward in the axial direction to form a bulging wall 24Fb that covers the shaft end of the crankshaft 40. Therefore, the suction cooling air is rectified on the outer periphery by the bulging wall 24Fb, and is smoothly guided to the cooling air introduction port 24Fe on the outer periphery of the annular bearing portion 24Fa and introduced into the transmission chamber 50C. The amount of cooling air introduced into the continuously variable transmission 50 can be increased.
The cooling air introduced into the transmission chamber 50C flows backward while cooling the belt-type continuously variable transmission 50, and is discharged from the cooling air outlet passage 24z at the rear of the transmission case cover 24.

  Since the substantially front half of the transmission case cover 24 is covered by the front side cover 26 from the side and the substantially rear half is covered by the rear side cover 27 from the side, the cooling air inlets 121e and 24Fe are provided on the front side. Covered by a cover 26.

As shown in FIGS. 12 and 13, the front side cover 26 corresponds to the front side wall portion 26F corresponding to the circular wall portion 24F of the transmission case cover 24 and the bulging portion 24e of the transmission case cover 24 above the front side wall portion 26F. A bulging portion 26e that bulges out is formed, and an extending portion 26E that extends at an acute angle by gradually decreasing the vertical width is formed behind the front side wall portion 26F.
The front side wall portion 26F covers the transmission case cover 24 from the front to the bottom with a peripheral wall 26C (see FIGS. 6 and 7).

The upper and lower side edges 26Ee forming an acute angle of the extending portion 26E are slightly bent inward (right side) until they intersect and connect at the rear end.
A front cover rib 26r protrudes from the inner surface (right side surface) of the extending portion 26E. As shown in FIG. 13, the front cover rib 26r is formed in a tapered shape with an acute angle substantially parallel to the upper and lower side edges 26Ee.
The upper and lower front cover ribs 26r formed in a taper form an arc rib portion 26rc that extends forward and is connected in a large arc on the inner surface of the front side wall portion 26F.

  Accordingly, the front cover rib 26r forms one closed loop, and the rib arc portion 26rc of the front side wall portion 26F has an annular outer ring protrusion to which the front filter element 120 of the transmission case cover 24 is fitted. It is arranged at a position surrounding the outer periphery of the portion 24Ff.

Further, a second front cover rib 26rr is formed on the inner surface of the front side wall portion 26F of the front side cover 26 so as to further surround the rib arc portion 26rc from the outer periphery, and horizontally from the inside of the rib arc portion 26rc. Some straight rectifying ribs 26rl that are parallel to each other protrude from the front upward.
Note that the front side cover 26 has mounting boss portions 26b formed at three locations on the front side wall portion 26F, on the front side and on the top and on the bottom.

  On the other hand, the rear side cover 27 covering the substantially rear half of the transmission case cover 24 is connected to the connecting portion 24C of the transmission case cover 24 and the rear dome with reference to FIGS. 14, 15 and 17 (and FIG. 6). The rear side wall 27R that covers the side of the wall 24R, the connecting portion 24C, and the peripheral wall 27C that covers from the upper side to the rear side of the rear dome wall 24R and covers the lower side. A recess 27D is formed which is recessed toward the connecting portion 24C of the transmission case cover 24.

The concave portion 27D of the rear side cover 27 is formed on the upper and lower sides of the extended portion 26E in which the bent edge 27De of the boundary recessed from the rear side wall portion 27R gradually extends to the rear side of the front side cover 26 and extends at an acute angle. It has the same shape so as to overlap with the edge 26Ee.
Accordingly, the concave portion 27D of the rear side cover 27 has its upper and lower bent edges 27De extending rearward and extending at an acute angle so that both rear ends intersect and are connected.

A rear cover rib 27r projects from the outer surface (left side surface) of the bottom wall 27Db of the recess 27D.
As shown in FIG. 14, the rear cover rib 27r is formed in a tapered shape at an acute angle substantially parallel to the upper and lower bent edges 27De.
The tapered upper and lower rear cover ribs 27r are connected at the rear ends, and the front ends protrude while opening slightly forward from the front ends of the rear side wall portions 27R.

A rectangular parallelepiped elastic body 125 is provided in contact with the rear end where the upper and lower rear cover ribs 27r meet from the rear, and is fixed to the bottom wall 27Db.
Further, on the inner surface (right side surface) of the rear side cover 27, an opening support portion 27p having a U-shaped cross section that supports the tip opening portion of the breather pipe at a required position along the upper peripheral wall 27C. A ceiling surface is formed to open to the right and extend to the left.

  The rear side cover 27 has mounting boss portions 27b at four positions of the upper and lower portions of the rear side wall portion 27R, the lower portion of the front rear cover rib 27r, and the bracket 27e extending slightly forward from the front portion. Is formed.

The rear side cover 27 is placed on the substantially rear half side surface of the transmission case cover 24, and the three mounting boss portions 27b of the rear upper and lower and front lower portions are fastened to the cover mounting boss 24Ri of the transmission case cover 24 by bolts 27B. When the rear side cover 27 is attached, and then the front side cover 26 is put on the substantially front half side surface of the transmission case cover 24, the rearward extending portion 26E of the transmission case cover 24 becomes the rear side cover. In this state, the three mounting bosses 26b are fastened to the cover mounting bosses 24Fi of the transmission case cover 24 by the bolts 26B to attach the front side cover 26 (FIG. 2). reference).
Note that the upper and rear mounting bosses 26b of the front side cover 26 are fastened together with the cover mounting bosses 24Fi of the transmission case cover 24 by bolts 26B common to the upper front mounting bosses 27b of the rear side cover 27.

FIG. 16 shows a side view of the state in which the front side cover 26 and the rear side cover 27 overlap each other at the extending portion 26E and the concave portion 27D, and FIG. 17 shows a cross-sectional view of the overlapping main portion.
A cooling air suction path 126 is formed between the rearward extending portion 26E of the front side cover 26 and the recessed portion 27D of the rear side cover 27 that overlap each other.

  In the cooling air intake passage 126, the front cover rib 26r formed in a tapered shape on the front side cover 26 has a positional relationship so as to cover the outer side of the rear cover rib 27r formed in a tapered shape on the rear side cover 27 substantially in parallel. Therefore, there is a rear cover rib 27r on the inner side surrounded by the front cover rib 26r that forms a closed loop together with the rib arc portion 26rc (see FIG. 16).

The crossing rear end connecting portion of the upper and lower front cover ribs 26r formed in a tapered shape is in contact with the elastic body 125 fixed to the concave bottom wall 27Db of the rear side cover 27, so that the front cover rib 26r extends from the concave bottom wall 27Db. A cooling air suction gap 127 exists between the vertical edge 26Ee of the extended portion 26E of the front side cover 26 and the vertical bent edge 27De constituting the concave portion 27D of the rear side cover 27. Are positioned (see FIG. 17).
Similarly, the rear cover rib 27r is located at a predetermined distance from the extending portion 26E of the front side cover 26 (see FIG. 17).

Accordingly, the cooling air suction gap 127 is formed in a long shape along the upper and lower side edges 26Ee extending at a sharp angle to the rear of the extending portion 26E of the front side cover 26, as indicated by broken line arrows in FIG. The cooling air is sucked into the cooling air intake passage 126 from the cooling air intake gap 127.
A front cover rib 26r and a rear cover rib 27r protrude from the cooling air intake passage 126 to form a labyrinth. The cooling air drawn from the cooling air intake gap 127 is guided in the order of the front cover rib 26r and the rear cover rib 27r. Thus, the cooling air intake passage 126 can be smoothly passed.

In this way, the cooling air intake passage 126 is guided by the front cover rib 26r and the rear cover rib 27r, and the intake cooling air is rectified by the rectifying rib 26rl in the front side cover 26 and flows forward to introduce the cooling air into the transmission case cover 24. Since it reaches the side of the filter element 120 disposed in the opening 24Fe, the air efficiently passes through the filter element 120 and is introduced into the transmission chamber 50C from the cooling air inlet 24Fe.
The cooling air introduced into the transmission chamber 50C flows rearward while cooling the belt-type continuously variable transmission 50, and is discharged from the cooling air outlet passage 24y at the lower center of the transmission case cover 24 and the cooling air outlet passage 24z at the rear portion. The

The transmission case 23 that accommodates the belt-type continuously variable transmission 50 together with the transmission case cover 24 swells to a position shifted to the right from the mating surface 23s of the transmission case cover 24 on the outer surface of the upper wall. A strip-shaped ridge 23T is formed so as to project backward from the protruding portion 23e in the front-rear direction (see FIGS. 4, 18, and 19).
A peripheral wall 27C of the rear side cover 27 that covers the transmission case cover 24 from the side covers the transmission case cover 24 as shown by a two-dot chain line in FIG. It extends to.

The protrusions 23T are respectively provided with locking holes 23p on the front and rear sides, and a notch 23v is formed at a predetermined position slightly forward of the rear locking holes 23p (see FIG. 4).
A driven pulley rotation sensor 150 is attached to the rear reduction gear portion 23c of the transmission case 23 so as to face the fixed pulley half 81s of the driven pulley 81 (see FIG. 4).

  The driven pulley rotation sensor 150 detects the rotation speed of the driven pulley 81 and uses it for gear shifting control by the speed change drive mechanism 60. A wiring 151 extending from the driven pulley rotation sensor 150 is connected to the upper side of the transmission case 23. It extends to the outside through a grommet 152 interposed in an arcuate notch provided on the mating surface at the rear of the wall.

Referring to FIG. 5, a vehicle speed sensor 155 penetrates and is held in a mounting hole formed in the upper wall of the reduction gear portion 23c of the transmission case 23, and the vehicle speed sensor 155 is fitted integrally with the rear axle 114. It penetrates toward the worn large-diameter gear 114a, and the detection part at the tip approaches the teeth of the large-diameter gear 114a to detect the rotational speed of the large-diameter gear 114a (rear axle 114), that is, the vehicle speed.
The wiring 156 extending from the vehicle speed sensor 155 is bundled together with the wiring 151 extending from the driven pulley rotation sensor 150 and extends forward along the left side surface of the transmission case cover 24 as a collective wiring 157 (FIG. 3). FIG. 18 and FIG. 21).

  On the flat left side surface of the connecting portion 24C between the circular wall portion 24F that is the front bulge portion and the dome wall 24R that is the rear bulge portion in the transmission case cover 24, there are substantially clamp mounting bosses 158 on the front and rear sides, respectively. It is formed in a vertically long rectangular parallelepiped shape (see FIGS. 8 and 18).

The clamp mounting boss 158 has a circular hole 158h drilled in the center of a substantially vertically long rectangular projecting surface, and protrusions 159 and 159 at the left and right along the long front side of the four sides of the rectangle. It protrudes toward the direction.
The protrusions 159 and 159 protrude slightly from the protruding surface of the clamp mounting boss 158.

The clamp 160 is attached to the clamp attachment boss 158 using the circular hole 158h.
Referring to FIG. 20, clamp 160 is formed with a holding portion 160 h that is bent from the surface of rectangular base plate-shaped clamp base portion 160 b and extends upward from the surface of clamp base portion 160 b. A locking protrusion 160p protrudes, and a retaining piece 160q is formed in an umbrella shape on the locking protrusion 160p.

When the locking projection 160p of the clamp 160 is passed through the circular hole 158h of the clamp mounting boss 158, as shown in FIG. Is locked to the clamp mounting boss 158.
The front side of the rectangular plate-shaped clamp base 160 b is in contact with the upper and lower protrusions 159 and 159, thereby preventing the rotation of the clamp 160. The protrusions 159 and 159 serve to prevent the clamp 160 from rotating.

Thus, the clamp 160 attached to the clamp mounting boss 158 while being prevented from rotating by the protrusions 159, 159 is maintained in a posture in which the holding portion 160h can hold the collective wiring 157 in the front-rear direction.
In the clamp 160, the clamp base portion 160b and the holding portion 160h form a substantially U shape, and the opening portion opened upward has a claw protruding to narrow the width. By pressing the collective wiring 157 into this opening, The holding portion 160h is elastically deformed to widen the opening, and the collective wiring 157 can be fitted into the curved bottom portion of the holding portion 160h, and the collective wiring 157 is held so that the clamp base portion 160b and the holding portion 160h are sandwiched.

  Note that a positioning ring 157r is fitted to both sides of the collective wiring 157 that are in contact with the holding portion 160h of the clamp 160, and when the collective wiring 157 is held by the clamp 160, the positioning wiring 157r on both sides also moves in the front-rear direction. Do not move.

  As described above, the collective wiring 157 extending from the driven pulley rotation sensor 150 and the vehicle speed sensor 155 disposed at the rear portion of the transmission case 23 is a circular wall portion that is a bulging portion before and after the transmission case cover 24. 24F and dome wall 24R are held by two front and rear clamps 160, 160 attached to the flat left side of the connecting portion 24C, which is a valley between the dome wall 24R, and arranged forward along the left side. However, even if the diameter of the wiring increases and the clamp 160 becomes somewhat large, it does not protrude further to the left than the dome wall 24R bulging to the left.

As shown in FIG. 21, the reduction gear cover 25, which accommodates the reduction gear mechanism 110 in the reduction gear portion 23c at the rear portion of the transmission case 23 and is attached from the right side, has an ABS above the opening 25h through which the rear axle 114 projects. A wheel speed sensor 165 is attached via a bracket 164.
The ABS wheel speed sensor 165 is provided with a detecting portion 165a adjacent to the annular plate attached to the hub of the rear wheel 17, and detects the wheel speed of the rear wheel 17 to be used for control of the antilock brake system ABS. Is.

The wiring 166 extending upward from the ABS wheel speed sensor 165 extends to the left above the transmission case 23 and is formed on the upper wall of the transmission case 23 in the front-rear direction, as shown in FIG. The rear end of the projected ridge 23T bends forward and is disposed forward along the left side surface of the ridge 23T.
Clamps 167 each having a retaining piece substantially the same as that of the clamp 160 are respectively locked in the locking holes 23p drilled before and after the protrusion 23T, and the wiring 166 is held by the clamps on the front and back.

The reduction gear portion 23c of the transmission case 23 and the reduction gear cover 25 constitute a reduction gear chamber 110C that houses the reduction gear mechanism 110. The ventilation connection penetrates the upper wall of the reduction gear portion 23c and communicates with the reduction gear chamber 110C. A pipe 170 is supported through the upper wall, and one end of a breather pipe 171 is fitted into a portion protruding to the outside of the ventilation connection pipe 170 (see FIG. 5).
Therefore, the breather pipe 171 communicates with the reduction gear chamber 110C and extends upward via the vent connection pipe 170.

As shown in FIG. 21, the breather pipe 171 extending upward from the reduction gear chamber 110C is bent to the left and extends along the upper surface of the transmission case 23, and is directed to the upper wall of the transmission case 23 in the front-rear direction. The protrusion 23T formed in this manner is fitted and positioned in the notch 23v and extends further to the left along the upper surface of the transmission case cover 24.
The breather pipe 171 extending in the left-right direction dives under the wiring 166 arranged in the front-rear direction along the ridge 23T and is also arranged in the front-rear direction. Pass over wiring 157.

A protective cover 180 is attached so as to cover the vehicle speed sensor 155 and the ABS wheel speed sensor 165 from the side of the reduction gear cover 25 to above the reduction gear portion 23c.
Referring to FIG. 21, the protective cover 180 is bent to the left from the upper end to the rear end of the side wall 180a to form an upper wall 180b and a rear wall 180c. The protective cover 180 is circular from the front ends of the side wall 180a and the upper wall 180b. A projecting portion 180d curved in an arc is formed to project forward.

The side wall 180a has a central portion that bulges to the right, and a circular hole 180h that faces the detecting portion 165a of the ABS wheel speed sensor 165 is formed in the lower portion of the bulged portion.
Note that three attachment holes 180e are formed in the side wall 180a.
Corresponding to the three mounting holes 180e of the protective cover 180, mounting bosses 181e are formed in the transmission case 23 and the reduction gear cover 25.

  When the protective cover 180 is placed on the reduction gear cover 25 from the side and attached to the mounting boss 181e with the mounting hole 180e fixed, the protective cover 180 extends from the vehicle speed sensor 155, the ABS wheel speed sensor 165, and both sensors 155 and 165. A part of the wirings 156, 166 is covered and protected by the protective cover 180, and the detection part 165a of the ABS wheel speed sensor 165 faces the circular hole 180h and slightly protrudes.

The arc-shaped projecting portion 180d projecting forward of the protective cover 180 presses the left bent portion of the breather pipe 171 extending from the reduction gear chamber 110C from the oblique side, thereby positioning in the left-right direction. (See FIG. 22).
The front opening 171a of the breather pipe 171 is formed on the inner surface (right side surface) of the rear side cover 27 when the rear side cover 27 is put on the transmission case cover 24 as shown in FIG. It is inserted and supported by the opening support part 27p (see also FIG. 15).

  The breather pipe 171 is positioned in the left-right direction by the projecting portion 180d of the protective cover 180, and is positioned in the front-rear direction by the notch 23v of the protrusion 23T, so that the distal end opening of the breather pipe 171 with respect to the transmission case cover 24 Since the front end opening 171a of the breather pipe 171 can be easily inserted into the opening support 27p when the rear side cover 27 is attached while the rear side cover 27 is attached, the attaching operation of the side cover 27 is easy. is there.

  As shown in FIG. 22, the collective wiring 157 is on the stepped portion 24 y where the dome wall 24 R of the transmission case cover 24 bulges, and between the transmission case cover 24 by the opening support portion 27 p of the rear side cover 27. It is positioned by being sandwiched.

  19 and 22, the upper portion of the peripheral wall 27C of the rear side cover 27 covers the transmission case cover 24 and the projection 23T of the transmission case 23, and further, a protective cover to the right of the projection 23T. The wirings 151, 156, 166 and the collective wiring 157 are all covered by the rear side cover 27 and the protective cover 180 since the upper wall 180b and the projecting part 180d are extended upward.

In addition, there is a gap between the upper portion of the peripheral wall 27C of the rear side cover 27 and the upper surface of the transmission case 23 and opens to the outside, but the outside and the rear side cover 27 are inside the opening. A ridge 23T is laid in the front-rear direction so as to cut off communication with the inside.
The wiring 166 extending from the ABS wheel speed sensor 165 is disposed along the left side surface opposite to the opening of the protrusion 23T.

  The wiring 166 and the collective wiring 157 disposed along the outer surface of the transmission case cover 24 extend upward along the outer surface of the bulging portion 24e at the front upper portion of the transmission case cover 24. Referring to FIG. 3, a wiring 191 extending from a hydraulic sensor 190 provided at the lower part of the front crankcase of the transmission case 23 is disposed upward so as to wind an oil filter 195 in front of the wiring 191 from below. The wirings 166, 157 and 191 are held together by a clamp 192 protruding from the side surface of the bulging portion 24e.

In the power unit 20 described above, according to the breather structure of the reduction gear chamber 110C, the breather pipe 171 extends outward from the reduction gear chamber 110C, so that it is easy to handle the breather pipe 171.
In other words, the breather pipe 171 can be easily positioned by fitting it into the notch 23v of the ridge 23T formed to project in the front-rear direction on the upper surface of the transmission case 23, and the rear side cover 27 can be assembled. At this time, since the opening 171a of the breather pipe 171 can be easily exposed to the opening support portion 27p provided on the inner surface of the rear side cover 27, the attaching work of the breather pipe 171 can be extremely facilitated.

  Since the protective cover 180 covering the reduction gear cover 25 from the side to the top covers the bent portion of the breather pipe 171, the bent portion of the breather pipe 171 is pressed and fixed to position the breather pipe 171 when the rear side cover 27 is assembled. The pipe 171 can be prevented from being deformed by being pushed, and the bent portion of the breather pipe 171 can be protected by the protective cover 180.

  The upper wall 27C that covers the upper surface of the transmission case cover 24 of the rear side cover 27 extends toward the transmission case 23 and covers the breather pipe 171 from above, so that the breather pipe 171 is connected to the protective cover 180 and the rear side cover. The whole is covered and protected by the cover 27, and the breather pipe 171 is not visible from the outside, and the appearance can be kept good.

  Since the protrusion 23T on the upper surface of the transmission case 23 extends to the front crankcase equivalent part, water, mud, etc. are formed between the transmission case cover 24 and the rear side cover 27 by the long protrusion 23T. It is possible to prevent foreign matter or the like from entering.

  Since the wiring 166 of the ABS wheel speed sensor 165 attached to the transmission case 23 is supported by the protrusion 23T, the protrusion 23T prevents intrusion of foreign matter, positioning of the breather pipe 171 and further wiring of the ABS wheel speed sensor 165. It has three types of functions of supporting 166, so that the number of parts can be reduced and the structure can be simplified.

  Collective wiring 157 of auxiliary machines such as driven pulley rotation sensor 150 and vehicle speed sensor 155 attached to transmission case 23 is sandwiched between opening support portion 27p provided on the inner surface of rear side cover 27 and transmission case cover 24. Therefore, the opening support part 27p on the inner surface of the rear side cover 27 can be used for positioning of the assembly wiring 157 of the auxiliary machine, and the number of parts can be reduced.

1 is a side view of a scooter type motorcycle with a power unit according to an embodiment of the present invention. It is an external appearance left view of a power unit. It is the left view which removed the front side cover used as the left exterior cover of the power unit, and the rear side cover. It is the left view which removed the transmission case cover of the same power unit. It is the right view which abbreviate | omitted one part of the power unit and removed the reduction gear cover. FIG. 3 is a cross-sectional view taken along line VI-VI in FIG. 2 and developed. It is the elements on larger scale of FIG. 4 is a left side view of the transmission case cover 24. FIG. It is the same right view. It is the XX sectional view taken on the line of FIG. It is the XI-XI sectional view taken on the line of FIG. It is a left view of a front side cover. It is the same right view. It is a left view of a rear side cover. It is the same right view. FIG. 6 is a left side view of a state in which a front side cover and a rear side cover are overlapped at an extension part 26E and a recess part 27D. It is the XVII-XVII sectional view taken on the line of FIG. It is a perspective view of the substantially latter half part of a power unit. It is the same top view. It is the XX-XX sectional view taken on the line in FIG. It is a perspective view of the state which decomposed | disassembled the protective cover of the rear part of the power unit. It is sectional drawing cut | disconnected along the breather pipe of the same power unit.

Explanation of symbols

20 ... Power unit, 21 ... Unit case, 22 ... Right unit case, 23 ... Transmission case, 23c ... Reduction gear part, 23T ... Projection, 23v ... Notch,
24 ... Transmission case cover, 24R ... Dome wall, 25 ... Reduction gear cover, 26 ... Front side cover, 27 ... Rear side cover, 27C ... Upper wall, 27p ... Opening support,
30 ... Internal combustion engine, 40 ... Crankshaft, 50 ... Belt-type continuously variable transmission, 110 ... Reduction gear mechanism, 110C ... Reduction gear chamber, 114 ... Rear axle,
150 ... driven pulley rotation sensor, 151 ... wiring, 155 ... vehicle speed sensor, 156 ... wiring, 157 ... collective wiring, 158 ... clamp mounting boss, 159 ... projection, 160 ... clamp, 165 ... wheel speed sensor for ABS, 166 ... wiring 167 ... Clamp, 170 ... Vent connection pipe, 171 ... Breather pipe, 180 ... Protective cover.

Claims (4)

A power unit that is swingably provided in a motorcycle, and a belt-type continuously variable transmission is provided on one side of a transmission case that also serves as a crankcase that rotatably supports a crankshaft of an internal combustion engine. A transmission case cover is placed on one side to cover the continuously variable transmission to form a transmission chamber, and a speed reduction device is provided on the other side of the rear portion of the transmission case to cover the speed reduction device. In the power unit that forms the reduction chamber by covering the rear part of the transmission case with the reduction gear cover from the other side,
A breather pipe that extends outwardly from the deceleration chamber is bent toward the transmission case side and extends along the upper surface of the transmission case and the upper surface of the transmission case cover, and a tip opening of the breather pipe extends toward the transmission case cover. Furthermore, facing the opening support provided on the inner surface of the side cover that covers the outer surface,
A protrusion is formed to project in the front-rear direction on the upper surface of the transmission case,
A breather structure of a deceleration chamber of a power unit, wherein the breather pipe is fitted and positioned in a notch formed in the protrusion. A protective cover that covers the speed reducer cover from the side to the top covers the bent portion of the breather pipe,
The breather structure of the deceleration chamber of the power unit according to claim 1, wherein an upper wall of the side cover covering the upper surface of the transmission case cover extends toward the transmission case and covers the breather pipe from above. The protrusion on the upper surface of the transmission case extends to the front crankcase equivalent part,
The breather structure of the deceleration chamber of the power unit according to claim 1 or 2, wherein the wiring of the auxiliary equipment attached to the transmission case is supported by the protrusion.   The wiring of an auxiliary machine attached to the transmission case is sandwiched between an opening support provided on the inner surface of the side cover and supporting the breather pipe and the transmission case cover. The breather structure of the deceleration chamber of the power unit according to any one of claims 3 to 4.

Images