Title of Invention

A MOTORCYCLE WITH A BELT-TYPE CONTINUOUSLY VARIABLE TRANSMISSION

Abstract A motorcycle 1 has a four cycle type engine 16 including a crank case 20 and a cylinder 21 extending upward from the crank case 20, a belt type continuously variable transmission 17 provided on one end of the crank case 20 in a vehicle width direction and a transmission case 36. Inside the transmission case 36, formed is a belt chamber 38 for housing the belt type continuously variable transmission 17. A part of the transmission case 36, the part being in front of a rear end 21e of a cylinder 21, is connected to an intake path 70 for leading air to the belt chamber 38. The intake path 70 extends upward from the transmission case 36.
Full Text MOTORCYCLE
BACKGROUND OF THE INVENTION
1. Field of the Invention
The invention relates to a motorcycle comprising a belt
type continuously variable transmission.
2. Description of the Related Art
Up to now, known has been a motorcycle comprising a belt
type continuously variable transmission (refer to
JP-B-61-40864 and JP-B-6-57547 mentioned below, for example) .
A belt type continuously variable transmission
comprises a primary sheave, a secondary sheave and a V-belt
wound around the primary sheave and the secondary sheave. The
belt type continuously variable transmission generates heat
to rise in temperature due to friction and such between the
V-belt and the respective sheaves in operation of the belt type
continuously variable transmission. Accordingly, it is
preferable to provide an intake path to supply the belt type
continuously variable transmission with air for cooling
through the intake path.
In JP-B-61-40864, disclosed is a power unit comprising
a two cycle type engine, a belt type continuously variable
transmission and an intake path provided at a position lower
than an upper end of a crank case of the engine for cooling
the transmission. In JP-B-6-57547, disclosed is a power unit
1

comprising a two cycle type engine, a belt type continuously
variable transmission and an intake path extending to a
position higher than a crank case of the engine for cooling
the transmission.
As a kind of motorcycle, known has been a so-called
off-road vehicle capable of running on a bad road. Mounting
a belt type continuously variable transmission is also
convenient for a rider even in the case of an off-road vehicle
since the belt type continuously variable transmission allows
a troublesome clutch operation to be made unnecessary.
In applying structures disclosed in JP-B-61-40864 and
JP-B-6-57547 to an off-road vehicle, however, there are
problems described below. Accordingly, a belt type
continuously variable transmission including an intake path
for cooling has not been applied to an off-road vehicle up to
now.
That is to say, in the case of providing an intake path
at a position lower than an upper end of a crank case like the
structure disclosed in JP-B-61-40864, water and dust rose from
the ground easily enter into the intake path. Therefore, it
is not preferable to apply the structure disclosed in
JP-B-61-40864 without any device in an off-road vehicle often
running on an unpaved road and the like.
Further, in an off-road vehicle, a cylinder of an engine
rises up and an angle between the cylinder and a horizontal
2

line is large. Moreover, in an off-road vehicle, a distance
between a power unit and the ground, namely, the minimum height
from the ground should be comparatively greatly secured. This
causes a cylinder and an exhaust pipe to be provided
collectively above the crank case of the engine. Accordingly,
the exhaust pipe or the cylinder is obstructive in extending
the intake path to a position higher than the crank case like
the structure disclosed in JP-B-6-57547.
As described above, it has been difficult to mount a belt
type continuously variable transmission including a
preferable intake path to an off-road vehicle or a motorcycle
in the form equal to an off-road vehicle by simply applying
a conventional technology as it is.
SUMMARY OF THE INVENTION
In view of the above, an object of the invention is to
provide an off-road vehicle or a motorcycle equal to an off-road
vehicle in which a belt type continuously variable
transmission including a preferable intake path is mounted.
A motorcycle in accordance with the invention is a
motorcycle comprising: a four stroke type engine including a
crank case and a cylinder extending upward or obliquely upward
to the front side from the crank case; a belt type continuously
variable transmission provided on one end of the crank case
in a vehicle width direction; a transmission case covering at
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least a part of the belt type continuously variable
transmission and having a belt chamber formed inside thereof
for housing the belt type continuously variable transmission;
and an intake path, at least a part thereof extending upward
or obliquely upward to the front side from a part of the
transmission case, the latter part being in front of a rear
end of the cylinder in side view, for leading air to the belt
chamber.
Another motorcycle in accordance with the invention is
a motorcycle comprising: a four cycle type engine including
a crank case and a cylinder extending upward from the crank
case; a belt type continuously variable transmission provided
on one end of the crank case in a vehicle width direction; a
transmission case covering at least a part of the belt type
continuously variable transmission and having a belt chamber
formed inside thereof for housing the belt type continuously
variable transmission; an intake path extending upward from
the transmission case in side view for leading air to the belt
chamber; and an exhaust pipe connected to the cylinder and
crossing with the intake path above the transmission case in
side view.
In accordance with the invention, it is possible to
provide in practice an off-road vehicle or a motorcycle equal
to an off-road vehicle in which a belt type continuously
variable transmission including a preferable intake path is
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mounted.
BRIEF DESCRIPTION OF THE DRAWINGS
Fig. 1 is a side view of a motorcycle in accordance with
Embodiment 1;
Fig. 2 is a side view of an integral part of a motorcycle
in accordance with Embodiment 1;
Fig. 3 is a flat view of an integral part of a motorcycle
in accordance with Embodiment 1;
Fig. 4 is a side view of an intake path;
Fig. 5 is a plan view of a fuel tank, a cover and the
like;
Fig. 6 is a sectional view of a power unit;
Fig. 7 is an exploded perspective view of a second case
block and an inner case;
Fig. 8 is an enlarged sectional view of a part of a power
unit in which the periphery of a centrifugal clutch is shown;
Fig. 9 is a side view of a motorcycle in accordance with
Embodiment 2; and
Fig. 10 is a plan view of an integral part of a motorcycle
in accordance with Embodiment 2;
DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS
The inventor of the application has found, as a result
of diligent study, that applying a four cycle type engine
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instead of a two cycle type engine allows an exhaust pipe to
be thinned and that extending an intake path for cooling of
a belt type continuously variable transmission upward from a
transmission case allows the intake path to be compactly
provided in a surplus space, which is created above the crank
case by thinning the exhaust pipe, and thus, has conceived the
invention. Embodiments of the invention will be described
hereinafter.

>
As shown in Figs. 1 to 3, in a motorcycle 1 in accordance
with Embodiment 1, an intake path 70 for cooling in a belt type
continuously variable transmission 17 extends on an outer side
of an exhaust pipe 41 in a vehicle width direction to the upper
side.
>
The motorcycle 1 in Embodiment l is a so-called off-road
type motorcycle. The motorcycle 1 comprises a body frame 2,
a fuel tank 24 supported on the body frame 2 and a seat 3
supported on the body frame 2 and provided behind the fuel tank
24. In the specification, back-and-forth and lateral
directions mean directions in view of a rider sitting on the
seat 3.
Further, "extending to the upper side" means a case of
extending upward as a whole in the specification. It is not
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limited to a case of extending vertically but includes a case
of extending obliquely upward. Similarly, a meaning of
"rearward" is not limited to a direction to the rear side along
a strictly back-and-forth direction but includes a direction
to the rear side along a direction inclining perpendicularly
or laterally to the back-and-forth direction. That is to say,
the "rearward" in the specification includes a so-called
obliquely rear side.
As shown in Fig. 2, the body frame 2 includes a head pipe
4, a down tube 5 extending downward from the head pipe 4, a
main tube 6 extending rearward from the head pipe 4 above the
down tube 5. A pair of right and left seat pillars 6a is divided
downward from a middle part of the main tube 6. A seat rail
7 extending rearward is connected to the seat pillar 6a. A
middle part of the seat rail 7 is connected to a rear end of
a backstay 8. A front end of the backstay 8 is connected to
a lower end of the seat pillar 6a.
A front fork 11 is inserted into the head pipe 4 as shown
in Fig. 1. On a lower end of the front fork 11, supported is
a front wheel 12. A pivot shaft 10 is inserted into the body
frame 2. On the pivot shaft 10, supported is a front end of
a rear arm 9 so as to be freely swingable. A rear wheel 13
is supported on a rear end of the rear arm 9.
A power unit 15 is supported on the body frame 2. The
power unit 15 comprises an engine 16 and a belt type

continuously variable transmission (referred to as a CVT,
hereinafter) 17 although a detail thereof is described later
(refer to Fig. 6).
The engine 16 comprises a crank case 20 and a cylinder
21 extending upward (more particularly, obliquely upward to
the front side) from the crank case 20. The cylinder 21
includes a cylinder body 21a and a cylinder head 22, as shown
in Fig. 2. As described above, the so-called cylinder head
22 is assumed to be included in the cylinder 21 in the
specification.
In the motorcycle 1 in accordance with Embodiment 1, the
cylinder 21 rises from the crank case 20 and slightly inclines
forward with respect to the vertical direction. In other words,
the cylinder 21 greatly inclines with respect to the horizontal
line. Further, as described later, the CVT 17 comprises a
primary sheave shaft 23a and a secondary sheave shaft 53. A
line LI connecting an axial core 23b of the primary sheave shaft
23a and an axial core 53b of the secondary sheave shaft 53
substantially crosses at right angles with a center line L2
of the cylinder 21 in side view. In Embodiment 1, the axial
core 53b of the secondary sheave shaft 53 is provided at a
position higher than the axial core 23b of the primary sheave
shaft 23a.
On the rear side of the cylinder 21, connected is an
intake pipe 40. The intake pipe 40 is provided with a
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carburetor 40a. A rear end of the intake pipe 40 is connected
to an air chamber 43 . The air chamber 43 is omitted from drawing
in Fig. 1.
An exhaust pipe 41 is connected on the front side of the
cylinder 21. The exhaust pipe 41 projects forward from the
cylinder 21 to curve or bend toward the rear side and extends
above the transmission case 36 or the crank case 20 to the rear
side (refer to Fig. 3, too). In side view, the exhaust pipe
41 crosses with the later-described intake path 70 above the
transmission case 36. As shown in Fig. 1, a rear end of the
exhaust pipe 41 is connected to a muffler 42.
Inside the transmission case 36, formed is a belt chamber
38 housing the CVT 17 although that is described in detail later
(refer to Fig. 6). As shown in Fig. 1, in front of a center
place of the transmission case 36 in the back-and-f orth
direction, connected is the intake path 70 for supplying the
belt chamber 38 with air for cooling. In detail, the intake
path 70 extends obliquely upward to the front side from a part
of the transmission case 36, the part located in front of a
rear end 21e of the cylinder 21, in side view. In Embodiment
1, the intake path 70 comprises an intake duct 71 extending
obliquely upward to the front side from the transmission case
36 and an air box 96 connected to an upper end of the intake
duct 71. The air box 96, however, is not necessarily provided.
The intake path 70 may be formed only from the intake duct 71.
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The air box 96 and the intake duct 71 may be formed into one
body or separate bodies.
The air box 96 is an air path forming member whose
appearance is formed into the shape of a box. In the intake
path 70 for cooling in the CVT 17, substantially no pulse of
air is generated differently from the intake pipe 40 of the
engine 16. Accordingly, the air box 96 may be not necessarily
a so-called air chamber for temporarily storing air. The air
box 96 may be one with a meander flow channel formed inside
thereof, for example. The air box 96 may be an air chamber,
of course.
As shown in Fig. 4, an air filter 95 is formed inside
the air box 96. An intake pipe 96a is connected on an upper
and rear side of the air box 96. An intake opening 96b opening
rearward is formed in the intake pipe 96a.
On sides of the fuel tank 24, provided is a pair of right
and left covers 14 formed so as to widen in the vehicle direction
toward the front side, as shown in Fig. 5. The air box 96 is
provided on the inner side of the cover 14, as shown in Fig.
1. The intake pipe 96a of the air box 96 is also provided on
the inner side of the cover 14. In other words, the air box
96 (including the intake pipe 96a) is covered with the cover
14 in side view. The intake path 70 extends to the inner side
of the cover 14 and a part of the intake pipe 70 is provided
on the inner side of the cover 14, as described above.
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In Embodiment 1, the exhaust pipe 41 and the intake duct
71 are provided on the right side of the cylinder 21, as shown
in Fig. 3. 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 are overlapped in side view (refer
to Fig. 1) . The exhaust pipe 41 extends rearward between the
cylinder 21 and the intake duct 71.
As shown in Fig. 3, a rear cushion unit 30 is provided
at the center part in the vehicle width direction. The rear
cushion unit 30 is provided between the main tube 6 and the
rear arm 9 to connect the main tube 6 and the rear arm 9, as
shown in Fig. 2. The motorcycle 1 in accordance with
Embodiment 1 includes only one rear cushion unit 30 and has
a so-called mono-suspension structure. The rear cushion unit
30 is not limited to one directly connected to the rear arm
9 but may be one connected to the rear arm 9 through a link.
Behind the rear cushion unit 30 and on the right side
of the air chamber 43, provided is a battery 50 as shown in
Fig. 3. The battery 50 is provided under the seat 3 (refer
to Fig. 1) . As shown in Fig. 3, the air chamber 43 is connected
to the intake pipe 43a opening rightward. A numeral 80 denotes
a footstep.
«Inner Structure of Power Unit»
Now, described will be an inner structure of the power
unit 15, made reference to Figs. 6 to 8.
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Fig. 6 shows a cross section of the power unit 15. As
shown in Fig. 5, the power unit 15 comprises the engine 16,
the CVT 17, a centrifugal clutch 18 and a reduction mechanism
19. The engine 16 is a four cycle type engine repeating a cycle
formed from an intake process, a compression process, a
combustion process and an exhaust process. In Embodiment 1,
the engine 16 is a four cycle single cylinder engine.
The engine 16 comprises the crank case 20, the cylinder
body 21a connected to the crank case 20 and the cylinder head
22 connected on the upper side of the cylinder body 21a. The
cylinder body 21a and the cylinder head 22 form the cylinder
21, as described before. The crank case 20 includes two
divided case blocks, namely, 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 faced to each other along the vehicle width direction.
In the crank case 20, housed is a crank shaft 23. The
crank shaft 23 extends in the vehicle width direction and is
provided horizontally. The crank shaft 23 is supported on the
first case block 20a through a bearing 24a and on the second
case block 20b through the 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 crank pin 28 is provided between a left crank arm 27a and
a right crank arm 27b of the crank shaft 23. The other end
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of the connecting rod 26 is connected to the crank pin 28.
In the cylinder head 22, formed are a concave 22a and
an intake port and an exhaust port, which are not shown and
communicate with the concave 22a. An ignition plug 29 is
inserted into the cylinder head 22. The intake port is
connected to the above-mentioned intake pipe 40 (refer to Fig.
1) . The exhaust port is connected to the exhaust pipe 41 (refer
to Fig. 1).
A generator case 35 for housing a generator 34 is mounted
to the left side of a front half of the first case block 20a.
A transmission case 36 for housing the CVT 17 is mounted to
the right side of the second case block 20b. Further, on the
right side of a rear half of the second case block 20b, formed
is an opening, which is covered with a clutch cover 37.
The transmission case 36 is formed independently from
the crank case 20. The transmission case 36 is formed from
an inner case 36a covering the inner side (the left side) of
the CVT 17 in the vehicle width direction and an outer case
36b covering the outer side (the right side) of the CVT 17 in
the vehicle width direction. The inner case 36a is mounted
on the right side of the crank case 20. The outer case 36b
is mounted on the right side of the inner case 36a. Inside
the inner case 36a and the outer case 36b, formed is the belt
chamber 38 housing the CVT 17. An intake opening 78 is formed
on an upper surface of the outer case 36b. The intake opening
13

78 is connected to the above-mentioned intake duct 71 (refer
to Fig. 1).
A right end of the crank shaft 23 passes through the
second case block 20b and the inner case 36a to extend to the
belt chamber 38. A primary sheave 51 of the CVT 17 is fitted
in the right end of the crank shaft 23. Accordingly, the
primary sheave 51 rotates in accordance with rotation of the
crank shaft 23. A right part of the crank shaft 23 (strictly,
a part on the right side of the bearing 24b) forms the primary
sheave shaft 23a.
On the other hand, a left end of the crank shaft 23 passes
through the first case block 20a to extend to the inner side
of the generation case 35. The generator 34 is mounted to the
left end of the crank shaft 23.
In a rear half of the crank case 20, the secondary sheave
shaft 53 in which a secondary sheave 52 is fitted is provided
parallel to the crank shaft 23. A part on the right side of
a center part of the secondary sheave shaft 53 is supported
on the clutch cover 37 through a bearing 54a. A part on the
left side of the secondary sheave shaft 53 is supported on a
left end of the second case block 20b through a bearing 54b.
The secondary sheave 52 is connected to a right end of the
secondary sheave shaft 53.
The CVT 17 comprises a V-belt 55 wound around the primary
sheave 51 and the secondary sheave 52 in addition to the primary
14

sheave 51 and the secondary sheave 52.
The primary sheave 51 comprises a fixed sheave body 51a
located on the outer side in the vehicle width direction and
a movable sheave body 51b located on the inner side in the
vehicle width direction and faced to the fixed sheave body 51a.
The fixed sheave body 51a is fixed to a right part of the primary
sheave shaft 23a and rotates together with the primary sheave
shaft 23a. The movable sheave body 51b is provided on the left
side of the fixed sheave body 51a and mounted to the primary
sheave shaft 23a so as to be freely slidable. Accordingly,
the movable sheave body 51b rotates together with the primary
sheave shaft 23a and is freely slidable in an axial direction
of the primary sheave shaft 23a. Between the fixed sheave body
51a and the movable sheave body 51b, formed is a belt groove
51c. A cam surface 56 is formed in a part of the left side
of the movable sheave body 51b. A cam plate 57 is provided
on the left side of the cam surface 56. A roller weight 58
is provided between the cam surface 56 of the movable sheave
body 51b and the cam plate 57.
The secondary sheave 52 comprises a fixed sheave body
52a located on the inner side in the vehicle width direction
and a movable sheave body 52b located on the outer side in the
vehicle width direction and faced to the fixed sheave body 52a.
The movable sheave body 52b is fixed to a right part of the
secondary sheave shaft 53. The movable sheave body 52b rotates
15

together with the secondary sheave shaft 53 and is freely
slidable in an axial direction of the secondary sheave shaft
53. On the right side of the secondary sheave 52, provided
is a compression coil spring 59. The movable sheave body 52b
receives leftward urging force from the compression coil
spring 59. An axial core part of the fixed sheave body 52a
is a cylindrical slide collar spline-fitted in the secondary
sheave shaft 53. Between the fixed sheave body 52a and the
movable sheave body 52b, formed is a V-shaped belt groove 52c.
The V-belt 55 is a so-called resin block belt comprising
plural resin blocks and a connection body for connecting the
resin blocks.
On the right side of the fixed sheave body 51a of the
primary sheave 51, formed are plural vanes 60 for ventilation.
The intake opening 78 formed on the upper surface of the
transmission case 36 is connected to the intake duct 71 (refer
to Fig. 1) , as described above. The intake opening 78 is formed
in a front half of the transmission case 36 (above the primary
sheave 51). Accordingly, the intake duct 71 is connected in
front of a rear end of the primary sheave 51.
When the fixed sheave body 51a rotates together with the
primary sheave shaft 23a in such a structure, air is led into
the belt chamber 38 through the intake opening 78 by means of
the vanes 60 while air in the belt chamber 38 is exhausted to
the outside. In Embodiment 1, the vane 60 is formed so as to
16

extend spirally outward in the diameter direction from the
center part of the fixed sheave body 51a in side view. A
concrete shape of the vane 60, however, is not limited at all.
The number of the vane 60 is also not limited at all. It may
be possible to provide a vaned wheel or the like, which is formed
separately from the fixed sheave body 51a, on the outer side
of 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, a front half
66 of the inner case 36a is formed into the shape of a bowl
projecting leftward while a rear half 67 of the inner case 36a
is formed into the shape of a bowl projecting rightward. In
the front half 66, formed is a hole 68 into which the primary
sheave shaft 23a (refer to Fig. 6) of the CVT 17 is inserted.
A hole 69 into which the secondary sheave shaft 53 (refer to
Fig. 6) of the CVT 17 is inserted is formed in the rear half
67. In Fig. 7, omitted from drawing is the clutch cover 37
(refer to Fig. 6) existing between the inner case 36a and the
second case block 20b.
Vents 72 are provided in the inner case 36a. In
Embodiment 1, the vent 72 is formed into a circular shape. The
vent 72 is three in number and provided on an upper side of
a center position of the inner case 36a in the perpendicular
direction. The shape and number of the vent 72, however, are
not limited at all.
17

In a lower part of a right part of the second case block
20b, formed are plural vents 73. In detail, the second case
block 20b includes a peripheral part 74 rising up rightward.
The peripheral part 74 is in the shape corresponding to a shape
of an outline of the transmission case 36. A lower part of
the peripheral part 74 is formed into the shape of a slit so
that a part of the lower part would be notched, to form a
so-called comb shape. Accordingly, a space 75 sectioned by
the second case block 20b and the inner case 36a communicates
with the outside of the power unit 15 (refer to Fig. 6) through
the vents 73. The space 75 is formed between the clutch cover
37 and the inner case 36a in a rear half of the second case
block 20b since the right side of the rear half of the second
case block 20b is covered with the clutch cover 37 (refer to
Fig. 6).
In the comb-shaped part of the peripheral part 74,
provided are reinforcement ribs 76. An oil pan 77 is provided
under the vents 73.
In accordance with such a structure, the air in the belt
chamber 38 is led to the space 75 through the vents 72 of the
inner case 36a to be exhausted toward the oil pan 77 through
the vents 73 of the second case block 20b. As a result, the
air is exhausted to the outside of the power unit 15.
Fig. 8 is an enlarged view of a part shown in Fig. 6.
As shown in Fig. 8, the centrifugal clutch 18 is mounted to
18

a left part of the secondary sheave shaft 53. The centrifugal
clutch 18 is a wet type multi-plate clutch and comprises a
substantially cylindrical clutch housing 81 and a clutch boss
82. The clutch housing 81 is spline-fitted in the secondary
sheave shaft 53 to rotate in a body with the secondary sheave
shaft 53. A plural number of ring-shaped clutch plates 83 are
mounted to the clutch housing 81.
A cylindrical gear 85 is fitted through a bearing 84 in
the periphery of the left part of the secondary sheave shaft
53 so as to be freely rotatable. The clutch boss 82 is provided
on the inner side in the diameter direction of the clutch plate
83 and on the outer side in the diameter direction of the gear
85 to engage with the gear 85. This causes the gear 85 to rotate
together with the clutch boss 82. On the outer side in the
diameter direction of the clutch boss 82, mounted are a plural
number of ring-shaped friction plates 86. The friction plates
86 are provided in line at intervals in an axial direction of
the secondary sheave shaft 53. Each of the friction plates
86 is provided between the adjacent clutch plates 83 and 83.
On the left side of the clutch housing 81, formed are
plural cam surfaces 87 . A roller weight 88 is provided between
the cam surface 87 and the most right clutch plate 83 faced
to the cam surface 87.
The centrifugal clutch 18 can be automatically switched
between an in-clutch state (namely, a state of connection) and
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an off-clutch state (namely, a state of disconnection) in
accordance with a size of centrifugal force operating on the
roller weight 88. In Fig. 8, a part lower than the secondary
sheave shaft 53 shows the in-clutch state while a part upper
than the secondary sheave shaft 53 shows the out-of-clutch
state.
The reduction mechanism 19 is provided between the
centrifugal clutch 18 and an output shaft (not shown). The
reduction mechanism 19 includes a transmission shaft 89
provided parallel to the secondary sheave shaft 53. The
transmission shaft 89 is supported on the first case block 20a
through a bearing 90 so as to be freely rotatable. The
transmission shaft 89 is also supported on the second case block
20b through a bearing 91 so as to be freely rotatable. On a
right end of the transmission shaft 89, provided is a first
transmission gear 92 engaging with the gear 85.
In a center part of the transmission shaft 89, provided
is a second transmission gear 93 having a diameter smaller than
that of the first transmission gear 92. The second
transmission gear 93 is arranged to engage with an output shaft
not shown or a gear, which is not shown and provided to the
output shaft.
Such a structure allows the clutch boss 82 and the output
shaft to be connected through the gear 85, the first
transmission gear 92, the transmission shaft 89, the second
20

transmission gear 93 and such. Accordingly, the output shaft
rotates in accordance with rotation of the clutch boss 82.
Around the output shaft, wound is a power transmission
mechanism for transmitting driving force of the output shaft
to the rear wheel 13 (refer to Fig. 1) such as a chain although
this is not shown in the drawings.
The structure of the power unit 15 has been described
above. Now, described will be a cooling operation of the CVT
17.
>
When the power unit 15 starts operating, the primary
sheave shaft 23a of the CVT 17 rotates and the vanes 60 of the
fixed sheave body 51a of the primary sheave 51 rotate in
accordance with the rotation of the primary sheave shaft 23a.
This results in generation of sucking force, which leads air
from the intake duct 71 toward the belt chamber 38.
Air is then sucked into the air box 96 through the intake
opening 96b (refer to Fig. 4) and passes through the filter
95 to be purified. After the above, the air is sucked into
the belt chamber 38 through the intake duct 71. The air sucked
into the belt chamber 38 flows in the periphery of the primary
sheave 51, the secondary sheave 52 and the V-belt 55 to cool
the primary sheave 51, the secondary sheave 52 and the V-belt
55.
The air having cooled the primary sheave 51, the
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secondary sheave 52 and the V-belt 55 is exhausted from the
belt chamber 38 through the vents 72 of the inner case 36a (refer
to Fig. 7) to flow into the space 75 between the inner case
36a and the second case block 20b. The air in the space 75
is exhausted to the outside of the power unit 15 through the
vents 73 formed in the lower part of the second case block 20b.
Such a flow of air causes the CVT 17 to be continuously and
regularly cooled.
As described above, in accordance with the motorcycle
according to Embodiment 1, the four cycle type engine 16 is
used while the intake path 70 extending upward from a part of
the transmission case 36, the part located in front of the rear
end 21e of the cylinder 21, in side view (refer to Fig. 1) is
provided for the purpose of supplying the CVT 17 with air for
cooling.
Thus, using the four cycle type engine 16 allows the
exhaust pipe 41 to be narrowed, so that a surplus space can
be secured above the crank case 20. Effectively using the
surplus space as a space for providing the intake path 70 allows
the intake path 70 to be provided upward without any obstruction
by the cylinder 21 and the exhaust pipe 41. Accordingly, water
and dust rose from the ground can be effectively prevented from
entering, differently from a case of providing the whole of
the intake path 70 at a position lower than the upper end of
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the crank case 20, so that the intake path 70 can be preferably
provided. Thus, in accordance with the motorcycle 1 according
to Embodiment 1, the CVT 17 including the preferable intake
path 70 can be mounted in spite of an off-road type vehicle.
Further, in accordance with the motorcycle 1 according
to Embodiment 1, the four cycle type engine 16 is used while
the intake path 70 extending upward from the transmission case
36 in side view (refer to Fig. 1) is provided for the purpose
of supplying the CVT 17 with air for cooling, and furthermore,
the exhaust pipe 41 is provided so as to cross with the intake
path 70 above the transmission case 36 in side view.
This also allows the intake path 70 to be provided upward
without any obstruction by the cylinder 21 and the exhaust pipe
41, so that the above-mentioned effect can be achieved.
In Embodiment 1, the intake path 70 extends upward from
a part of the transmission case 36, the part in front of the
rear end 21e of the cylinder 21, in side view. Such a structure
is more preferable. The intake path 70, however, may extend
from a part located behind the rear end 21e of the cylinder
21 so long as the exhaust pipe 41 crosses with the intake path
70 above the transmission case 36 in side view.
Especially, the intake path 70 is arranged to be provided
adjacently to the cylinder 21 in the vehicle width direction
in Embodiment 1. Further, the exhaust pipe 41 is arranged to
extend between the cylinder 21 and the intake path 70. These
23

allow the cylinder 21, the exhaust pipe 41 and the intake path
70 to be provided at a higher density, so that the vehicle can
be miniaturized.
Moreover, in accordance with Embodiment 1, a sucking part
of the intake path 70, namely, the intake pipe 96a is provided
on an inner side of the cover 14. Accordingly, the cover 14
effectively prevents mud or the like from entering the intake
path 70. Further, there is a certain degree of space on the
inner side of the cover 14. Effectively using the space as
a space for providing a part of the intake path 70 (mainly the
air box 96, in Embodiment 1) allows the whole vehicle to be
made compact.
In addition, the intake opening 96b of the intake pipe
96a is open rearward in accordance with Embodiment 1. This
causes mud or the like to be further prevented from entering
the intake path 70. Further, rainwater can be effectively
prevented from entering the intake path 70 even in the case
of rain. Particularly, the intake opening 96b of the intake
pipe 96a is faced to the inner surface of the cover 14 in
Embodiment 1. Accordingly, mud or the like can be prevented
more from entering through the intake opening 96b.
As described above, in accordance with Embodiment 1, the
air box 96 including the air filter 95 built in is provided
on the inner side of the cover 14. The air filter 95 is
comparatively large component. Putting a comparatively large
24

space on the inner side of the cover 14 to practical use like
Embodiment 1, however, allows the air filter 95 to be prevented
from projecting to the outside, so that the air filter 95 can
be provided compactly.

The motorcycle 1 in accordance with Embodiment 2 is one
in which the exhaust pipe 41 in Embodiment 1 is changed in
location, as shown in Figs. 9 and 10. In the following
description, a component similar to that of Embodiment 1 is
marked with the same reference signs and numerals and a part
different from Embodiment 1 is only described.
As shown in Figs. 9 and 10, the exhaust pipe 41 extends
rearward on the left side of the cylinder 21 in Embodiment 2.
That is to say, the exhaust pipe 41 extends rearward on a side
opposite to a side of the intake path 70 of the cylinder 21.
The air chamber 43 is provided on the right side of the
rear cushion unit 30 and the battery 50, as shown in Fig. 10.
In Embodiment 2, the intake pipe 43a of the air chamber 43 opens
leftward.
As described above, in accordance with Embodiment 2, the
intake duct 71 of the intake path 70 is provided on the right
side of the cylinder 21, the exhaust pipe 41 is provided on
the left side of the cylinder 21 and the intake path 70 and
the exhaust pipe 41 are provided on sides opposite to each other.
Accordingly, the intake path 70 can extend upward from the
25

transmission case 36 without obstruction by the exhaust pipe
41, so that a preferable intake path 70 can be achieved.
Moreover, the exhaust pipe 41 does not project in the vehicle
width direction even in the case that the exhaust pipe 41, the
cylinder 21 and the intake path 70 are in line in the vehicle
width direction since the engine 16 is a four cycle type engine
and the exhaust pipe 41 is thin. This allows the intake path
70 for cooling in the CVT 17 to be preferably provided without
increasing the size of the vehicle.
>
The invention is not limited to the above-mentioned
embodiments but can be carried out in practice in other various
kinds of embodiments. In the above embodiments, the
motorcycle 1 is an off-road vehicle. The off-road vehicle in
the above context means a motorcycle suitable for running on
a bad road. The off-road vehicle, however, may be one running
on a paved road, of course. Further, the motorcycle in
accordance with the invention may be a motorcycle of a type
equal to an off-road vehicle. For example, the motorcycle in
accordance with the invention may be a motorcycle unsuitable
for running on a bad road in practice although it is an off-road
type motorcycle in appearance.
In the above embodiments, the whole of the intake path
70 extends upward from a part located in front of the rear end
21e of the cylinder 21. The embodiments, however, are only
26

examples. It may be possible that only a part of the intake
path 70 extends from a part located in front of the rear end
21e of the cylinder 21. Moreover, the whole of the air box
96 including the sucking part 96a is provided on the inner side
of the cover 14 in the embodiments. It may be possible, however,
that a part of the air box 96 or a part of the sucking part
96a is only provided on the outer side of the cover 14.
>
As mentioned above, "extending upward" in the
specification means a case of extending upward as a whole. It
is not limited to a case of extending vertically upward but
includes a case of extending obliquely upward. Accordingly,
a case of extending obliquely upward to the front side or the
like corresponds to the case of "extending upward" in the
specification.
Furthermore, "opening rearward" is not limited to a case
of opening rearward along the back-and-forth direction, namely,
a case of opening rearward in the strict sense of the word.
"Opening rearward" in the specification also includes a case
of opening rearward along a direction inclining
perpendicularly or laterally to the back-and-f orth direction,
namely, a case of opening toward the so-called obliquely rear
side.
As mentioned above, "a cylinder" in the specification
includes not only a cylindrical member into which a piston is
27

inserted, namely, a cylinder body but also a so-called cylinder
head.
As described above, the invention is useful for a
motorcycle.
28

WE CLAIM:
1. A motorcycle comprising:
a four cycle type engine including a crank case and a
cylinder extending upward from the crank case;
a belt type continuously variable transmission provided
on one end of the crank case in a vehicle width direction;
a transmission case covering at least a part of the belt
type continuously variable transmission and having a belt
chamber formed inside thereof for housing the belt type
continuously variable transmission; and
an intake path, at least a part thereof extending upward
from a part of the transmission case, the latter part being
in front of a rear end of the cylinder in side view, for leading
air to the belt chamber.
2. The motorcycle as claimed in Claim 1, further
comprising:
a fuel tank; and
a pair of right and left covers provided on sides of the
fuel tank and formed so as to widen toward the front side in
the vehicle width direction in flat view,
wherein the intake path has at least a part provided on
an inner side of the cover and includes a sucking part for
sucking air in.
29

3. The motorcycle as claimed in Claim 2, wherein
an intake opening opening rearward is formed in the
sucking part.
4. The motorcycle as claimed in Claim 1, further
comprising:
a fuel tank; and
a pair of right and left covers provided on sides of the
fuel tank and formed so as to widen toward the front side in
the vehicle width direction in flat view,
wherein the intake path includes an intake duct extending
upward from the transmission case and a box-shaped member
provided inside the cover, connected to the intake duct and
housing an air filter therein.
5. The motorcycle as claimed in Claim 1, wherein
the intake path is adjacent to the cylinder in the vehicle
width direction.
6. The motorcycle as claimed in Claim 5, further
comprising:
an exhaust pipe connected to the cylinder and extending
rearward between the cylinder and the intake path.
7. The motorcycle as claimed in Claim 5, further
30

comprising:
an exhaust pipe connected to the cylinder and extending
rearward on a side of the cylinder, the side being opposite
to a side of the intake path.
8. The motorcycle as claimed in Claim 1, wherein:
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 a center of rotation of the primary
sheave and a secondary sheave shaft positioned at a center of
rotation of the secondary sheave; and
a line connecting an axial core of the primary sheave
shaft and an axial core of the secondary sheave shaft crosses
substantially at right angles with a center line of the cylinder
in side view.
9. A motorcycle comprising:
a four cycle type engine including a crank case and a
cylinder extending upward from the crank case;
a belt type continuously variable transmission provided
on one end of the crank case in a vehicle width direction;
a transmission case covering at least a part of the belt
type continuously variable transmission and having a belt
chamber formed inside thereof for housing the belt type
31

continuously variable transmission;
an intake path extending upward from the transmission
case in side view for leading air to the belt chamber; and
an exhaust pipe connected to the cylinder and crossing
with the intake path above the transmission case in side view.
10. The motorcycle as claimed in Claim 9, further
comprising:
a fuel tank; and
a pair of right and left covers provided on sides of the
fuel tank and formed so as to widen toward the front side in
the vehicle width direction in flat view,
wherein the intake path has at least a part provided on
an inner side of the cover and includes a sucking part for
sucking air in.
11. The motorcycle as claimed in Claim 10, wherein
an intake opening opening rearward is formed in the
sucking part.
12. The motorcycle as claimed in Claim 9, further
comprising:
a fuel tank; and
a pair of right and left covers provided on sides of the
fuel tank and formed so as to widen toward the front side in
32

the vehicle width direction in flat view,
wherein the intake path includes an intake duct extending
upward from the transmission case and a box-shaped member
provided inside the cover, connected to the intake duct and
housing an air filter therein.
13. The motorcycle as claimed in Claim 9, wherein
the intake path is adjacent to the cylinder in the vehicle
width direction.
14. The motorcycle as claimed in Claim 13, wherein
the exhaust pipe extends rearward between the cylinder
and the intake path.
15. The motorcycle as claimed in Claim 13, wherein
the exhaust pipe extends rearward on a side of the
cylinder, the side being opposite to a side of the intake path.
16. The motorcycle as claimed in Claim 9, wherein:
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 a center of rotation of the primary
sheave and a secondary sheave shaft positioned at a center of
rotation of the secondary sheave, and
33

a line connecting an axial core of the primary sheave
shaft and an axial core of the secondary sheave shaft crosses
substantially at right angles with a center line of the cylinder
in side view.


A motorcycle 1 has a four cycle type engine 16 including
a crank case 20 and a cylinder 21 extending upward from the
crank case 20, a belt type continuously variable transmission
17 provided on one end of the crank case 20 in a vehicle width
direction and a transmission case 36. Inside the transmission
case 36, formed is a belt chamber 38 for housing the belt type
continuously variable transmission 17. A part of the
transmission case 36, the part being in front of a rear end
21e of a cylinder 21, is connected to an intake path 70 for
leading air to the belt chamber 38. The intake path 70 extends
upward from the transmission case 36.

Documents:

01535-kol-2007-abstract.pdf

01535-kol-2007-claims.pdf

01535-kol-2007-correspondence 1.1.pdf

01535-kol-2007-correspondence others.pdf

01535-kol-2007-description complete.pdf

01535-kol-2007-drawings.pdf

01535-kol-2007-form 1.pdf

01535-kol-2007-form 2.pdf

01535-kol-2007-form 3.pdf

01535-kol-2007-form 5.pdf

01535-kol-2007-gpa.pdf

01535-kol-2007-priority document.pdf

01535-kol-2007-translated copy of priority document.pdf

1535-KOL-2007-(11-05-2012)-ABSTRACT.pdf

1535-KOL-2007-(11-05-2012)-AMANDED CLAIMS.pdf

1535-KOL-2007-(11-05-2012)-CORRESPONDENCE.pdf

1535-KOL-2007-(28-03-2012)-ABSTRACT.pdf

1535-KOL-2007-(28-03-2012)-AMANDED CLAIMS.pdf

1535-KOL-2007-(28-03-2012)-CORRESPONDENCE.pdf

1535-KOL-2007-(28-03-2012)-DESCRIPTION (COMPLETE).pdf

1535-KOL-2007-(28-03-2012)-DRAWINGS.pdf

1535-KOL-2007-(28-03-2012)-FORM-1.pdf

1535-KOL-2007-(28-03-2012)-FORM-2.pdf

1535-KOL-2007-(28-03-2012)-FORM-3.pdf

1535-KOL-2007-(28-03-2012)-OTHERS.pdf

1535-KOL-2007-(31-01-2012)-ABSTRACT.pdf

1535-KOL-2007-(31-01-2012)-AMANDED CLAIMS.pdf

1535-KOL-2007-(31-01-2012)-DESCRIPTION (COMPLETE).pdf

1535-KOL-2007-(31-01-2012)-DRAWINGS.pdf

1535-KOL-2007-(31-01-2012)-EXAMINATION REPORT REPLY RECIEVED.pdf

1535-KOL-2007-(31-01-2012)-FORM 1.pdf

1535-KOL-2007-(31-01-2012)-FORM 2.pdf

1535-KOL-2007-(31-01-2012)-FORM 3.pdf

1535-KOL-2007-(31-01-2012)-OTHERS.pdf

1535-KOL-2007-(31-01-2012)-PA.pdf

1535-KOL-2007-(31-01-2012)-PETITION UNDER RULE 137.pdf

1535-KOL-2007-CORRESPONDENCE 1.2.pdf

1535-KOL-2007-CORRESPONDENCE 1.3.pdf

1535-KOL-2007-CORRESPONDENCE OTHERS 1.1.pdf

1535-KOL-2007-CORRESPONDENCE OTHERS 1.3.pdf

1535-KOL-2007-EXAMINATION REPORT.pdf

1535-KOL-2007-FORM 18 1.1.pdf

1535-KOL-2007-FORM 18.pdf

1535-KOL-2007-FORM 3.pdf

1535-KOL-2007-FORM 5.pdf

1535-KOL-2007-GPA.pdf

1535-KOL-2007-GRANTED-ABSTRACT.pdf

1535-KOL-2007-GRANTED-CLAIMS.pdf

1535-KOL-2007-GRANTED-DESCRIPTION (COMPLETE).pdf

1535-KOL-2007-GRANTED-DRAWINGS.pdf

1535-KOL-2007-GRANTED-FORM 1.pdf

1535-KOL-2007-GRANTED-FORM 2.pdf

1535-KOL-2007-GRANTED-LETTER PATENT.pdf

1535-KOL-2007-GRANTED-SPECIFICATION.pdf

1535-KOL-2007-OTHERS 1.1.pdf

1535-KOL-2007-OTHERS.pdf

1535-KOL-2007-PRIORITY DOCUMENT.pdf

1535-KOL-2007-REPLY TO EXAMINATION REPORT.pdf

1535-KOL-2007-TRANSLATED COPY OF PRIORITY DOCUMENT.pdf

abstract-01535-kol-2007.jpg


Patent Number 253407
Indian Patent Application Number 1535/KOL/2007
PG Journal Number 29/2012
Publication Date 20-Jul-2012
Grant Date 18-Jul-2012
Date of Filing 07-Nov-2007
Name of Patentee YAMAHA HATSUDOKI KABUSHIKI KAISHA
Applicant Address 2500 SHINGAI, IWATA-SHI, SHIZUOKA
Inventors:
# Inventor's Name Inventor's Address
1 YOUSUKE ISHIDA C/O. YAMAHA HATSUDOKI KABUSHIKI KAISHA 2500 SHINGAI, IWATA-SHI, SHIZUOKA 4388501
PCT International Classification Number B62M7/02; F16H57/04
PCT International Application Number N/A
PCT International Filing date
PCT Conventions:
# PCT Application Number Date of Convention Priority Country
1 2006-322066 2006-11-29 Japan
2 2007-016494 2007-01-26 Japan