JP2008185055A - Motorcycle - Google Patents

Abstract

An off-road vehicle equipped with a belt-type continuously variable transmission having a suitable intake passage, or a motorcycle according to an off-road vehicle is provided.
A motorcycle includes a four-cycle engine having a crankcase and a cylinder extending upward from the crankcase, and a belt type disposed on one end side of the crankcase in the vehicle width direction. A continuously variable transmission 17 and a transmission case 36 are provided. A belt chamber 38 that houses the belt type continuously variable transmission 17 is formed inside the transmission case 36. An intake passage 70 that guides air to the belt chamber 38 is connected to a portion of the transmission case 36 in front of the rear end 21 e of the cylinder 21. The intake passage 70 extends upward from the transmission case 36.
[Selection] Figure 1

Description

  The present invention relates to a motorcycle including a belt type continuously variable transmission.

  Conventionally, a motorcycle including a belt type continuously variable transmission is known (see, for example, Patent Documents 1 and 2 below).

  The belt type continuously variable transmission includes a primary sheave, a secondary sheave, and a V-belt wound around the primary sheave and the secondary sheave. During operation of the belt-type continuously variable transmission, the belt-type continuously variable transmission generates heat due to friction between the V-belt and each sheave and the temperature rises. Therefore, it is preferable to provide an intake passage and supply cooling air to the belt-type continuously variable transmission through the intake passage.

Patent Document 1 discloses a power unit including a two-cycle engine, a belt-type continuously variable transmission, and an intake passage for cooling the transmission disposed at a position lower than the upper end of the engine crankcase. ing. Patent Document 2 discloses a power unit including a two-cycle engine, a belt-type continuously variable transmission, and a transmission cooling intake passage that extends to a position higher than the crankcase of the engine.
Japanese Examined Patent Publication No. 61-40864 Japanese Patent Publication No. 6-57547

  Incidentally, so-called off-road vehicles capable of traveling on rough roads are known as one type of motorcycle. Even in an off-road vehicle, if a belt-type continuously variable transmission can be mounted, troublesome clutch operation is unnecessary, which is convenient for riders.

  However, when the configurations disclosed in Patent Documents 1 and 2 are applied to off-road vehicles, there are the following problems. For this reason, a belt type continuously variable transmission having a cooling intake passage has not been conventionally applied to off-road vehicles.

  That is, if the intake passage is arranged at a position lower than the upper end of the crankcase as in the configuration disclosed in Patent Document 1, water and dust that are rolled up from the ground are likely to enter the intake passage. For this reason, in an off-road vehicle that often travels on an unpaved road or the like, it is not preferable to employ the configuration disclosed in Patent Document 1 unless some measures are taken.

  Further, in an off-road vehicle, the engine cylinder stands up and the angle between the cylinder and the horizon is large. In an off-road vehicle, the distance between the power unit and the ground, that is, the minimum ground clearance must be relatively large. Therefore, a cylinder and an exhaust pipe are concentratedly arranged above the crankcase of the engine. Therefore, if the intake passage is extended to a position higher than the crankcase as in the configuration disclosed in Patent Document 2, the exhaust pipe or the cylinder becomes an obstacle.

  As described above, it is difficult to mount a belt type continuously variable transmission having a suitable intake passage to an off-road vehicle or a motorcycle according to an off-road vehicle simply by diverting the conventional technology. there were.

  The present invention has been made in view of this point, and an object of the present invention is to provide an off-road vehicle equipped with a belt-type continuously variable transmission having a suitable intake passage, or a motorcycle according to an off-road vehicle. Is to provide.

  A motorcycle according to the present invention includes a four-stroke engine having a crankcase and a cylinder extending upward or obliquely upward from the crankcase, and a belt-type non-rotating motor disposed on one end side in the vehicle width direction of the crankcase. A stepped transmission, a transmission case that covers at least a portion of the belt-type continuously variable transmission, and in which a belt chamber that houses the belt-type continuously variable transmission is formed; An intake passage that extends upward or obliquely upward from the front side of the rear end of the cylinder in the transmission case and guides air to the belt chamber.

  In addition, another motorcycle according to the present invention includes a four-cycle engine having a crankcase and a cylinder extending upward from the crankcase, and a belt-type non-motor disposed on one end side of the crankcase in the vehicle width direction. A transmission case, a transmission case that covers at least a part of the belt-type continuously variable transmission, and in which a belt chamber that houses the belt-type continuously variable transmission is formed; An intake passage that extends upward and guides air to the belt chamber, and an exhaust pipe that is connected to the cylinder and intersects the intake passage above the transmission case in a side view.

  According to the present invention, it is possible to realize an off-road vehicle equipped with a belt-type continuously variable transmission having a suitable intake passage or a motorcycle according to an off-road vehicle.

  As a result of earnest research, the inventor of the present application can reduce the exhaust pipe by adopting a four-cycle engine instead of the two-cycle engine, and provide a cooling intake passage for the belt-type continuously variable transmission. By extending upward from the transmission case, it has been found that the intake passage can be compactly arranged in a marginal space above the crankcase generated by narrowing the exhaust pipe. It came to. Embodiments of the present invention will be described below.

<Embodiment 1>
<< Outline of this embodiment >>
As shown in FIGS. 1 to 3, in the motorcycle 1 according to this embodiment, the cooling intake passage 70 of the belt-type continuously variable transmission 17 is located above the exhaust pipe 41 through the outside in the vehicle width direction. It is what extends.

<< Overall structure of motorcycle >>
The motorcycle 1 of the present embodiment is a so-called off-road type motorcycle. The motorcycle 1 includes a vehicle body frame 2, a fuel tank 24 supported by the vehicle body frame 2, and a seat 3 supported by the vehicle body frame 2 and disposed on the rear side of the fuel tank 24. In the present specification, the front-rear and left-right directions refer to directions seen from the occupant seated on the seat 3.

  Further, in this specification, “extending upward” means a case of extending upward as a whole, and includes not only a case of extending vertically upward but also a case of extending obliquely upward. Similarly, “rear” is not limited to the rear direction strictly along the front-rear direction, but also includes the rear direction along the direction tilted up and down or left and right from the front-rear direction. That is, so-called diagonally backward is also included in the “rear” in this specification.

  As shown in FIG. 2, the vehicle body frame 2 includes a head pipe 4, a down tube 5 extending downward from the head pipe 4, and a main tube 6 extending rearward from the head pipe 4 above the down tube 5. And. From the middle part of the main tube 6, a pair of left and right seat pillars 6a branch downward. A seat rail 7 extending rearward is connected to the seat pillar 6a. A rear end portion of the backstay 8 is connected to the middle portion of the seat rail 7. The front end portion of the backstay 8 is connected to the lower end portion of the seat pillar 6a.

  As shown in FIG. 1, a front fork 11 is inserted through the head pipe 4. A front wheel 12 is supported at the lower end of the front fork 11. A pivot shaft 10 is inserted through the body frame 2, and a front end portion of the rear arm 9 is supported on the pivot shaft 10 so as to be swingable. A rear wheel 13 is supported at the rear end of the rear arm 9.

  A power unit 15 is supported on the body frame 2. Although details will be described later (see FIG. 6), the power unit 15 includes an engine 16 and a belt-type continuously variable transmission (hereinafter referred to as CVT) 17.

  The engine 16 includes a crankcase 20 and a cylinder 21 that extends upward from the crankcase 20 (more specifically, obliquely upwardly forward). As shown in FIG. 2, the cylinder 21 has a cylinder body 21 a and a cylinder head 22. Thus, in this specification, the so-called cylinder head 22 is also included in the cylinder 21.

  In the motorcycle 1 of the present embodiment, the cylinder 21 stands from the crankcase 20 and is slightly inclined forward from the vertical direction. In other words, the cylinder 21 is greatly inclined from the horizon. Further, as will be described later, the CVT 17 includes a primary sheave shaft 23a and a secondary sheave shaft 53, and a line L1 connecting the shaft center 23b of the primary sheave shaft 23a and the shaft center 53b of the secondary sheave shaft 53 in a side view. And the center line L2 of the cylinder 21 are substantially orthogonal to each other. In the present embodiment, the shaft center 53b of the secondary sheave shaft 53 is disposed at a position higher than the shaft center 23b of the primary sheave shaft 23a.

  An intake pipe 40 is connected to the rear side of the cylinder 21. The intake pipe 40 is provided with a carburetor 40a. An air chamber 43 is connected to the rear end of the intake pipe 40. In FIG. 1, the air chamber 43 is not shown.

  An exhaust pipe 41 is connected to the front side of the cylinder 21. The exhaust pipe 41 protrudes forward from the cylinder 21, then curves or bends backward, and extends backward through the transmission case 36 or the crankcase 20 (see also FIG. 3). In side view, the exhaust pipe 41 intersects an intake passage 70 described later above the transmission case 36. As shown in FIG. 1, a muffler 42 is connected to the rear end of the exhaust pipe 41.

  Although details will be described later, a belt chamber 38 that houses the CVT 17 is formed inside the transmission case 36 (see FIG. 6). As shown in FIG. 1, an intake passage 70 that supplies cooling air to the belt chamber 38 is connected to the front side of the transmission case 36 in the front-rear direction center position. Specifically, the intake passage 70 extends obliquely upward and forward from the front side of the rear end 21e of the cylinder 21 in the transmission case 36 in a side view. In the present embodiment, the intake passage 70 includes an intake duct 71 extending obliquely upward and forward from the transmission case 36 and an air box 96 connected to the upper end of the intake duct 71. However, the air box 96 is not always necessary. The intake passage 70 may be formed only by the intake duct 71. The air box 96 and the intake duct 71 may be formed integrally or may be separate.

  The air box 96 is an air passage forming member whose outer shape is formed in a box shape. Unlike the intake pipe 40 of the engine 16, substantially no air pulsation occurs in the cooling intake passage 70 of the CVT 17. Therefore, the air box 96 may not be a so-called air chamber that temporarily accumulates air. For example, the air box 96 may have a meandering flow path formed therein. Of course, the air box 96 may be an air chamber.

  As shown in FIG. 4, an air filter 95 is provided inside the air box 96. An intake pipe 96 a is connected to the upper side and the rear side of the air box 96. An intake port 96b that opens rearward is formed in the intake pipe 96a.

  As shown in FIG. 5, a pair of left and right covers 14 formed to extend in the vehicle width direction toward the front are provided on the sides of the fuel tank 24. As shown in FIG. 1, the air box 96 is disposed inside the cover 14. An intake pipe 96 a of the air box 96 is also disposed inside the cover 14. In other words, the air box 96 (including the intake pipe 96a) is covered with the cover 14 in a side view. Thus, the intake passage 70 extends to the inside of the cover 14, and a part of the intake passage 70 is disposed inside the cover 14.

  As shown in FIG. 3, in the present embodiment, the exhaust pipe 41 and the intake duct 71 are disposed on the right side of the cylinder 21. The intake duct 71 is adjacent to the cylinder 21 in the vehicle width direction. In other words, the intake duct 71 and the cylinder 21 overlap in a side view (see FIG. 1). The exhaust pipe 41 passes between the cylinder 21 and the intake duct 71 and extends rearward.

  As shown in FIG. 3, a rear cushion unit 30 is provided at the center in the vehicle width direction. As shown in FIG. 2, the rear cushion unit 30 is provided between the main tube 6 and the rear arm 9 so as to connect the main tube 6 and the rear arm 9. The motorcycle 1 of the present embodiment includes only one rear cushion unit 30 and has a so-called monosus structure. The rear cushion unit 30 is not limited to the one directly connected to the rear arm 9, and may be one connected to the rear arm 9 via a link.

  As shown in FIG. 3, a battery 50 is provided behind the rear cushion unit 30 and on the right side of the air chamber 43. The battery 50 is disposed below the seat 3 (see FIG. 1). As shown in FIG. 3, an intake pipe 43 a that opens to the right side is connected to the air chamber 43. Reference numeral 80 represents a foot step.

<Internal configuration of power unit>
Next, the internal configuration of the power unit 15 will be described with reference to FIGS.

  FIG. 6 is a view showing a cross section of the power unit 15. As shown in FIG. 5, the power unit 15 includes an engine 16, a CVT 17, a centrifugal clutch 18, and a speed reduction mechanism 19. The engine 16 is a four-cycle engine that repeats a cycle including an intake stroke, a compression stroke, a combustion stroke, and an exhaust stroke. In the present embodiment, the engine 16 is a four-cycle single cylinder engine.

  The engine 16 includes a crankcase 20, a cylinder body 21a connected to the crankcase 20, and a cylinder head 22 connected to the upper side of the cylinder body 21a. As described above, the cylinder main body 21a and the cylinder head 22 form the cylinder 21. The crankcase 20 has two divided case blocks, that is, a first case block 20a located on the left side and a second case block 20b located on the right side. The first case block 20a and the second case block 20b are attached to each other along the vehicle width direction.

  A crankshaft 23 is accommodated in the crankcase 20. The crankshaft 23 extends in the vehicle width direction and is disposed horizontally. The crankshaft 23 is supported by the first case block 20a via a bearing 24a, and is supported by the second case block 20b via a bearing 24b.

  A piston 25 is slidably inserted into the cylinder 21. One end of a connecting rod 26 is connected to the piston 25. A crankpin 28 is provided between the left crank arm 27a and the right crank arm 27b of the crankshaft 23. The other end of the connecting rod 26 is connected to the crankpin 28.

  The cylinder head 22 has a recess 22a and an intake port and an exhaust port (not shown) communicating with the recess 22a. A spark plug 29 is inserted into the cylinder head 22. The intake pipe 40 (see FIG. 1) is connected to the intake port, and the exhaust pipe 41 (see FIG. 1) is connected to the exhaust port.

  A generator case 35 that houses the generator 34 is attached to the left side of the front half of the first case block 20a. A transmission case 36 that houses the CVT 17 is attached to the right side of the second case block 20b. Further, an opening is formed on the right side of the second half of the second case block 20 b, and this opening is closed by the clutch cover 37.

  The transmission case 36 is formed independently of the crankcase 20, and includes an inner case 36a that covers the inner side (left side) of the CVT 17 in the vehicle width direction and an outer case 36b that covers the outer side (right side) of the CVT 17 in the vehicle width direction. It consists of and. The inner case 36a is attached to the right side of the crankcase 20, and the outer case 36b is attached to the right side of the inner case 36a. A belt chamber 38 that accommodates the CVT 17 is formed inside the inner case 36a and the outer case 36b. An intake port 78 is formed on the upper surface of the outer case 36b. The intake duct 71 (see FIG. 1) is connected to the intake port 78.

  The right end portion of the crankshaft 23 passes through the second case block 20b and the inner case 36a and extends to the belt chamber 38. A primary sheave 51 of the CVT 17 is fitted into the right end portion of the crankshaft 23. Therefore, the primary sheave 51 rotates according to the rotation of the crankshaft 23. The right portion of the crankshaft 23 (strictly, the portion on the right side of the bearing 24b) forms a primary sheave shaft 23a.

  On the other hand, the left end portion of the crankshaft 23 passes through the first case block 20 a and extends into the generator case 35. A generator 34 is attached to the left end portion of the crankshaft 23.

  A secondary sheave shaft 53 into which a secondary sheave 52 is fitted is disposed in the latter half of the crankcase 20 in parallel with the crankshaft 23. The right side portion of the central portion of the secondary sheave shaft 53 is supported by the clutch cover 37 via a bearing 54a. The left side portion of the secondary sheave shaft 53 is supported by the left end portion of the second case block 20b via a bearing 54b. The secondary sheave 52 is connected to the right end of the secondary sheave shaft 53.

  In addition to the primary sheave 51 and the secondary sheave 52, the CVT 17 includes a V belt 55 wound around the primary sheave 51 and the secondary sheave 52.

  The primary sheave 51 includes a fixed sheave body 51a positioned on the outer side in the vehicle width direction, and a movable sheave body 51b positioned on the inner side in the vehicle width direction and facing the fixed sheave body 51a. The fixed sheave body 51a is fixed to the right side of the primary sheave shaft 23a and rotates together with the primary sheave shaft 23a. The movable sheave body 51b is disposed on the left side of the fixed sheave body 51a and is slidably attached to the primary sheave shaft 23a. Therefore, the movable sheave body 51b rotates with the primary sheave shaft 23a and is slidable in the axial direction of the primary sheave shaft 23a. A belt groove 51c is formed between the fixed sheave body 51a and the movable sheave body 51b. A cam surface 56 is formed on the left side of the movable sheave body 51b, and a cam plate 57 is disposed on the left side of the cam surface 56. A roller weight 58 is disposed between the cam surface 56 and the cam plate 57 of the movable sheave body 51b.

  The secondary sheave 52 includes a fixed sheave body 52a positioned on the inner side in the vehicle width direction and a movable sheave body 52b positioned on the outer side in the vehicle width direction and facing the fixed sheave body 52a. The movable sheave body 52 b is attached to the right side portion of the secondary sheave shaft 53. The movable sheave body 52 b rotates with the secondary sheave shaft 53 and is slidable in the axial direction of the secondary sheave shaft 53. A compression coil spring 59 is provided on the right side of the secondary sheave 52, and the movable sheave body 52 b receives a leftward biasing force from the compression coil spring 59. The shaft portion of the fixed sheave body 52a is a cylindrical slide collar, and is spline-fitted to the secondary sheave shaft 53. A V-shaped belt groove 52c is formed between the fixed sheave body 52a and the movable sheave body 52b.

  The V-belt 55 is a so-called resin block belt provided with a plurality of resin blocks and a connecting body that connects these resin blocks.

  A plurality of blades 60 for blowing air are formed on the right side portion of the fixed sheave body 51 a of the primary sheave 51. Further, as described above, the intake duct 71 (see FIG. 1) is connected to the intake port 78 formed on the upper surface of the transmission case 36. The intake port 78 is formed in the front half of the transmission case 36 (above the primary sheave 51). Therefore, the intake duct 71 is connected to the front side of the rear end of the primary sheave 51.

  With such a configuration, when the fixed sheave body 51a rotates together with the primary sheave shaft 23a, air is guided into the belt chamber 38 through the intake port 78 by the blade 60, and the air in the belt chamber 38 is discharged to the outside. . In the present embodiment, the blade 60 is formed so as to spirally extend radially outward from the center portion of the fixed sheave body 51a in a side view. However, the specific shape of the blade 60 is not limited at all, and the number of the blades 60 is not limited at all. Moreover, you may make it provide the impeller etc. of the separate body from the fixed sheave body 51a outside the fixed sheave body 51a.

  FIG. 7 is a perspective view of the second case block 20b and the inner case 36a. As shown in FIG. 7, the front half 66 of the inner case 36a is formed in a bowl shape that bulges to the left, and the rear half 67 of the inner case 36a is formed in a bowl shape that bulges to the right. The front half 66 is formed with a hole 68 through which the primary sheave shaft 23a of the CVT 17 (see FIG. 6) is inserted. The latter half 67 is formed with a hole 69 through which the secondary sheave shaft 53 (see FIG. 6) of the CVT 17 is inserted. In FIG. 7, the illustration of the clutch cover 37 (see FIG. 6) interposed between the inner case 36 a and the second case block 20 b is omitted.

  Ventilation holes 72 are provided in the inner case 36a. In the present embodiment, the vent holes 72 are formed in a circular shape, and three are formed above the intermediate position in the vertical direction of the inner case 36a. However, the shape and the number of the ventilation holes 72 are not limited at all.

  A plurality of ventilation holes 73 are formed below the right side portion of the second case block 20b. Specifically, the second case block 20 b includes a peripheral portion 74 that is erected toward the right side, and the peripheral portion 74 has a shape corresponding to the contour shape of the transmission case 36. And the lower side of the peripheral part 74 is formed in a slit shape in which a part thereof is cut out, and has a so-called comb shape. Therefore, the space 75 defined by the second case block 20b and the inner case 36a communicates with the outside of the power unit 15 (see FIG. 6) through the ventilation holes 73. Since the right side of the rear half of the second case block 20b is covered with the clutch cover 37, the space 75 is located between the clutch cover 37 and the inner case 36a in the rear half of the second case block 20b. (See FIG. 6).

  Reinforcing ribs 76 are provided on the comb-like portion of the peripheral edge portion 74. An oil pan 77 is provided below the ventilation hole 73.

  With the configuration as described above, the air in the belt chamber 38 is guided to the space 75 through the ventilation hole 72 of the inner case 36a, and further discharged toward the oil pan 77 through the ventilation hole 73 of the second case block 20b. . As a result, the air is discharged to the outside of the power unit 15.

  FIG. 8 is an enlarged view of a part of FIG. As shown in FIG. 8, the centrifugal clutch 18 is attached to the left side portion of the secondary sheave shaft 53. The centrifugal clutch 18 is a wet multi-plate clutch, and includes a substantially cylindrical clutch housing 81 and a clutch boss 82. The clutch housing 81 is spline-fitted to the secondary sheave shaft 53 and rotates integrally with the secondary sheave shaft 53. A plurality of ring-shaped clutch plates 83 are attached to the clutch housing 81.

  A cylindrical gear 85 is rotatably fitted around the left side portion of the secondary sheave shaft 53 via a bearing 84. The clutch boss 82 is disposed on the radially inner side of the clutch plate 83 and on the radially outer side of the gear 85, and meshes with the gear 85. Therefore, the gear 85 rotates together with the clutch boss 82. A plurality of ring-shaped friction plates 86 are attached to the outer side of the clutch boss 82 in the radial direction. These friction plates 86 are arranged at intervals along the axial direction of the secondary sheave shaft 53, and each friction plate 86 is disposed between adjacent clutch plates 83, 83.

  A plurality of cam surfaces 87 are formed on the left side of the clutch housing 81. A roller weight 88 is disposed between the cam surface 87 and the rightmost clutch plate 83 facing the cam surface 87.

  In the centrifugal clutch 18, the clutch-in state (that is, the connected state) and the clutch-off state (that is, the disconnected state) are automatically switched depending on the magnitude of the centrifugal force acting on the roller weight 88. In FIG. 8, the lower side of the secondary sheave shaft 53 indicates the clutch-in state, and the upper side indicates the clutch-out state.

  The speed reduction mechanism 19 is interposed between the centrifugal clutch 18 and an output shaft (not shown). The speed reduction mechanism 19 has a speed change shaft 89 disposed in parallel with the secondary sheave shaft 53. The transmission shaft 89 is rotatably supported by the first case block 20a via a bearing 90. The transmission shaft 89 is rotatably supported by the second case block 20b via a bearing 91. A first transmission gear 92 that meshes with the gear 85 is provided at the right end of the transmission shaft 89.

  A second transmission gear 93 having a smaller diameter than the first transmission gear 92 is provided at the center of the transmission shaft 89. The second transmission gear 93 is disposed so as to mesh with an output shaft (not shown) or a gear (not shown) provided on the output shaft.

  With such a configuration, the clutch boss 82 and the output shaft are connected via the gear 85, the first transmission gear 92, the transmission shaft 89, the second transmission gear 93, and the like. Therefore, the output shaft rotates according to the rotation of the clutch boss 82. Although not shown, a power transmission mechanism such as a chain for transmitting the driving force of the output shaft to the rear wheel 13 (see FIG. 1) is wound around the output shaft.

  The above is the configuration of the power unit 15. Next, the cooling operation of the CVT 17 will be described.

<< CVT cooling operation >>
When the power unit 15 is activated, the primary sheave shaft 23a of the CVT 17 rotates, and the blade 60 of the fixed sheave body 51a of the primary sheave 51 rotates accordingly. As a result, a suction force that guides air from the intake duct 71 into the belt chamber 38 is generated.

  Then, air is sucked into the air box 96 through the air inlet 96b (see FIG. 4), and the air passes through the filter 95 to be purified, and is then sucked into the belt chamber 38 through the air intake duct 71. The air sucked into the belt chamber 38 flows around the primary sheave 51, the secondary sheave 52, and the V belt 55, and cools the primary sheave 51, the secondary sheave 52, and the V belt 55.

  The air that has cooled the primary sheave 51, the secondary sheave 52, and the V-belt 55 is discharged from the belt chamber 38 through the ventilation hole 72 (see FIG. 7) of the inner case 36a, and between the inner case 36a and the second case block 20b. It flows into the space 75. And the air in the said space 75 is discharged | emitted outside the power unit 15 through the ventilation hole 73 formed in the lower part of the 2nd case block 20b. The CVT 17 is continuously and constantly cooled by the air flow as described above.

<< Effect of this embodiment >>
As described above, according to the motorcycle 1 according to the present embodiment, the four-cycle engine 16 is adopted, and in order to supply the cooling air to the CVT 17, in the side view (see FIG. 1), the speed change is performed. An intake passage 70 extending upward from the front side of the rear end 21e of the cylinder 21 in the machine case 36 is provided.

  As described above, by adopting the four-cycle engine 16, the exhaust pipe 41 can be made thinner, and a marginal space can be secured above the crankcase 20. Then, by effectively utilizing this extra space as an installation space for the intake passage 70, the intake passage 70 can be arranged upward without being obstructed by the cylinder 21 and the exhaust pipe 41. Therefore, unlike the case where the entirety of the intake passage 70 is provided at a position lower than the upper end of the crankcase 20, it is possible to effectively suppress the intrusion of water, dust and the like that are wound up from the ground, and the intake passage 70 is suitably disposed. It becomes possible to do. Therefore, according to the motorcycle 1 of the present embodiment, it is possible to mount the CVT 17 having a suitable intake passage 70 despite being an off-road type vehicle.

  In addition, according to the motorcycle 1 according to the present embodiment, the four-cycle engine 16 is adopted, and in order to supply cooling air to the CVT 17, in a side view (see FIG. 1), from the transmission case 36. An intake passage 70 extending upward is provided, and the exhaust pipe 41 is disposed so as to intersect the intake passage 70 above the transmission case 36 in a side view.

  Also by this, the intake passage 70 can be arranged upward without being obstructed by the cylinder 21 and the exhaust pipe 41, and the above-described effects can be obtained.

  In the present embodiment, the intake passage 70 extends upward from the front side of the rear end 21e of the cylinder 21 in the transmission case 36 in a side view. Although such a form is more preferable, as long as the exhaust pipe 41 intersects the intake passage 70 above the transmission case 36 in a side view, the intake passage 70 extends from a portion on the rear side of the rear end 21e of the cylinder 21. May be.

  In particular, in the present embodiment, the intake passage 70 is arranged adjacent to the cylinder 21 in the vehicle width direction. Further, the exhaust pipe 41 is arranged so as to pass between the cylinder 21 and the intake passage 70. Thereby, the cylinder 21, the exhaust pipe 41, and the intake passage 70 can be arranged with higher density, and the vehicle can be downsized.

  Further, according to the present embodiment, the suction portion of the intake passage 70, that is, the intake pipe 96 a is disposed inside the cover 14. Therefore, intrusion of mud or the like into the intake passage 70 is effectively suppressed by the cover 14. In addition, since there is a certain amount of empty space inside the cover 14, the space of the entire vehicle can be made compact by effectively using the space as a part of the intake passage 70 (mainly, the air box 96 in the present embodiment). Can be achieved.

  Further, according to the present embodiment, the intake port 96b of the intake pipe 96a is opened rearward. Therefore, intrusion of mud or the like into the intake passage 70 is further suppressed. In addition, it is possible to effectively prevent rainwater from entering the intake passage 70 even during rainy weather. In particular, in the present embodiment, the intake port 96 b of the intake pipe 96 a faces the inner surface of the cover 14. Therefore, it is possible to further suppress the intrusion of mud or the like from the air inlet 96b.

  As described above, according to the present embodiment, the air box 96 including the air filter 95 is disposed inside the cover 14. Although the air filter 95 is a relatively large part, the air filter 95 can be prevented from protruding to the outside by utilizing a relatively large empty space inside the cover 14 as in the present embodiment. It is possible to arrange the air filter 95 in a compact manner.

<Embodiment 2>
As shown in FIGS. 9 and 10, the motorcycle 1 according to the second embodiment is obtained by changing the position of the exhaust pipe 41 in the first embodiment. In the following description, the same parts as those in the first embodiment are denoted by the same reference numerals, and only the parts different from the first embodiment will be described.

  As shown in FIGS. 9 and 10, in the present embodiment, the exhaust pipe 41 extends rearward through the left side of the cylinder 21. That is, the exhaust pipe 41 extends rearward through the opposite side of the cylinder 21 from the intake passage 70 side.

  As shown in FIG. 10, the air chamber 43 is disposed on the right side of the rear cushion unit 30 and the battery 50. In the present embodiment, the intake pipe 43a of the air chamber 43 opens to the left side.

  As described above, according to the present embodiment, the intake duct 71 of the intake passage 70 is disposed on the right side of the cylinder 21, the exhaust pipe 41 is disposed on the left side of the cylinder 21, and the intake passage 70 and the exhaust pipe 41 are mutually connected. It is arranged on the opposite side. Therefore, the intake passage 70 can be extended upward from the transmission case 36 without being obstructed by the exhaust pipe 41, and a suitable intake passage 70 can be realized. The engine 16 is a four-cycle engine, and since the exhaust pipe 41 is thin, the exhaust pipe 41, the cylinder 21, and the intake passage 70 are arranged in the vehicle width direction, but the exhaust pipe 41 protrudes in the vehicle width direction. There is nothing. Therefore, it is possible to suitably arrange the intake passage 70 for cooling the CVT 17 without increasing the size of the vehicle.

<< Other modifications >>
The present invention is not limited to the above-described embodiment, and can be implemented in various other forms. In the above-described embodiment, the motorcycle 1 is an off-road vehicle, but the off-road vehicle here is a motorcycle suitable for running on a rough road, but may be one that runs on a paved road. Of course. Further, the motorcycle according to the present invention may be a motorcycle of a type according to an off-road vehicle. For example, the motorcycle according to the present invention is an off-road type motorcycle in appearance, but may actually be a motorcycle that is not suitable for driving on rough roads.

  In the embodiment, the entire intake passage 70 extends upward from a portion on the front side of the rear end 21 e of the cylinder 21. However, the above embodiment is merely an example, and only a part of the intake passage 70 may extend upward from a portion on the front side of the rear end 21e of the cylinder 21. In the embodiment, the entire air box 96 including the suction part 96 a is disposed inside the cover 14. However, a part of the air box 96 or a part of the suction part 96 a may be arranged outside the cover 14.

<< Definition of terms etc. in this specification >>
As described above, in this specification, “extending upward” means a case of extending upward as a whole, and includes not only a case of extending vertically upward but also a case of extending obliquely upward. Accordingly, an aspect that extends obliquely forward and upward also corresponds to “extend upward” as used herein.

  Further, “opening backward” is not limited to the case of opening backwards along the front-rear direction, that is, the case of opening backwards in a strict sense. A case of opening rearward along a direction inclined from the front-rear direction to the upper or lower side or the left-right direction, that is, a case of opening toward the oblique rear is also included in “opening rearward” in this specification.

  As described above, the “cylinder” in this specification includes not only a cylindrical member into which a piston is inserted, that is, a cylinder body but also a so-called cylinder head.

  As described above, the present invention is useful for motorcycles.

1 is a side view of a motorcycle according to a first embodiment. 1 is a side view of a main part of a motorcycle according to a first embodiment. FIG. 2 is a plan view of a main part of the motorcycle according to the first embodiment. It is a side view of an intake passage. It is a top view, such as a fuel tank and a cover. It is sectional drawing of a power unit. It is a disassembled perspective view of a 2nd case block and an inner side case. It is a fragmentary sectional view of the power unit which expands and shows the centrifugal clutch vicinity. 3 is a side view of a motorcycle according to Embodiment 2. FIG. FIG. 6 is a plan view of a main part of a motorcycle according to a second embodiment.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 Motorcycle 14 Cover 16 Engine 17 Belt type continuously variable transmission 20 Crankcase 21 Cylinder 21e Cylinder rear end 23a Primary sheave shaft 23b Shaft center of primary sheave shaft 24 Fuel tank 36 Transmission case 38 Belt chamber 41 Exhaust pipe 51 Primary Sheave 52 Secondary sheave 53 Secondary sheave shaft 53b Shaft center of secondary sheave shaft 55 V-belt 70 Intake passage 71 Intake duct 95 Air filter 96 Air box (box-like member)
96a Suction part 96b Suction port L1 Line connecting the axis of the primary sheave shaft and the axis of the secondary sheave shaft L2 Center line of the cylinder

Claims (16)

A four-cycle engine having a crankcase and a cylinder extending upward from the crankcase;
A belt-type continuously variable transmission disposed on one end side in the vehicle width direction of the crankcase;
A transmission case that covers at least a part of the belt-type continuously variable transmission, and in which a belt chamber for accommodating the belt-type continuously variable transmission is formed;
In a side view, at least a portion of the transmission case extends upward from a portion of the transmission case that is more forward than the rear end of the cylinder, and an intake passage that guides air to the belt chamber
Motorcycle equipped with. The motorcycle according to claim 1,
A fuel tank,
A pair of left and right covers that are disposed on the side of the fuel tank in a plan view and are formed so as to spread in the vehicle width direction toward the front;
The motorcycle, wherein at least a part of the intake passage is disposed inside the cover and has an intake portion for sucking air. The motorcycle according to claim 2,
A motorcycle in which an intake port that opens rearward is formed in the suction portion. The motorcycle according to claim 1,
A fuel tank,
A pair of left and right covers that are disposed on the side of the fuel tank in a plan view and are formed so as to spread in the vehicle width direction toward the front;
The intake passage includes an intake duct extending upward from the transmission case, and a box-shaped member disposed inside the cover, connected to the intake duct and containing an air filter therein. Motorcycle. The motorcycle according to claim 1,
The intake passage is a motorcycle adjacent to the cylinder in the vehicle width direction. The motorcycle according to claim 5,
A motorcycle further comprising an exhaust pipe connected to the cylinder and extending rearwardly between the cylinder and the intake passage. The motorcycle according to claim 5,
The motorcycle further comprising an exhaust pipe connected to the cylinder and extending rearward through a side opposite to the intake passage side of the cylinder. The motorcycle according to claim 1,
The belt-type continuously variable transmission includes a primary sheave, a secondary sheave, a V-belt wound around the primary sheave and the secondary sheave, a primary sheave shaft positioned at the rotation center of the primary sheave, and the secondary sheave A secondary sheave shaft located at the rotation center of
A motorcycle in which a line connecting the axis of the primary sheave shaft and the axis of the secondary sheave shaft and a center line of the cylinder are substantially orthogonal in a side view. A four-cycle engine having a crankcase and a cylinder extending upward from the crankcase;
A belt-type continuously variable transmission disposed on one end side in the vehicle width direction of the crankcase;
A transmission case that covers at least a part of the belt-type continuously variable transmission, and in which a belt chamber for accommodating the belt-type continuously variable transmission is formed;
An intake passage that extends upward from the transmission case in a side view and guides air to the belt chamber;
An exhaust pipe connected to the cylinder and intersecting the intake passage above the transmission case in a side view;
Motorcycle equipped with. The motorcycle according to claim 9,
A fuel tank,
A pair of left and right covers that are disposed on the side of the fuel tank in a plan view and are formed so as to spread in the vehicle width direction toward the front;
The motorcycle, wherein at least a part of the intake passage is disposed inside the cover and has an intake portion for sucking air. The motorcycle according to claim 10,
A motorcycle in which an intake port that opens rearward is formed in the suction portion. The motorcycle according to claim 9,
A fuel tank,
A pair of left and right covers that are disposed on the side of the fuel tank in a plan view and are formed so as to spread in the vehicle width direction toward the front;
The intake passage includes an intake duct extending upward from the transmission case, and a box-shaped member disposed inside the cover, connected to the intake duct and containing an air filter therein. Motorcycle. The motorcycle according to claim 9,
The intake passage is a motorcycle adjacent to the cylinder in the vehicle width direction. The motorcycle according to claim 13,
The exhaust pipe extends backward between the cylinder and the intake passage. The motorcycle according to claim 13,
The exhaust pipe extends rearward through a side of the cylinder opposite to the intake passage side. The motorcycle according to claim 9,
The belt-type continuously variable transmission includes a primary sheave, a secondary sheave, a V-belt wound around the primary sheave and the secondary sheave, a primary sheave shaft positioned at the rotation center of the primary sheave, and the secondary sheave A secondary sheave shaft located at the rotation center of
A motorcycle in which a line connecting the axis of the primary sheave shaft and the axis of the secondary sheave shaft and a center line of the cylinder are substantially orthogonal in a side view.

Images