Title of Invention

ENGINE WITH ATTACHED AXIAL GAP TYPE ROTATING ELECTRIC MACHINE

Abstract An engine with the attached axial gap type rotating electric machine includes a crank case, a rotor, and a stator. A crank shaft, that is driven to rotate around a center axis by a piston, is inserted within the crank case such the crank shaft can rotate. The rotor is fixed to an end section side of the crank shaft at the outside of the crank case, and includes a plurality of permanent magnets. The stator is fixed to the crank case with the crank shaft inserted therein, and faces the permanent magnets in the center axis direction. The stator includes a fixed stator that has first teeth, and a moveable stator that has second teeth. A gap between the first teeth and the second teeth that generates magnetic resistance can be varied by rotating the second teeth around the center axis relative to the first teeth. A drive mechanism is provided that relatively rotates the first stator and the second stator.
Full Text ENGINE WITH ATTACHED AXIAL GAP TYPE ROTATING ELECTRIC MACHINE
This application claims priority from Japanese Patent
Application No. 2007-026941 filed on February 6, 2007.
BACKGROUND OF THE INVENTION
1. Field of the Invention
The present invention relates to an engine with an
attached axial gap type rotating electric machine.
2. Description of the Related Art
JP-A-2006-271040 discloses an engine with an attached
axial gap type rotating electric machine. This engine with
the attached axial gap type rotating electric machine is
provided with a crank case, a crank shaft that is driven to
rotate around a center axis by a piston within the crank case,
and an axial gap type rotating electric machine that is
connected via a belt-type continuously variable transmission
to one end of the crank shaft within the crank case.
The axial gap type rotating electric machine is disposed
in parallel to the crank shaft, and is provided with a rotating
electric machine side shaft that has one end that is linked
to the belt-type continuously variable transmission, a rotor
that is fixed to the other end of the rotating electric machine
side shaft, and a stator that is fixed to the crank case at
a position further toward the other end than the rotor, with
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the rotating electric machine side shaft inserted
therethrough.
A plurality of permanent magnets are disposed orthogonal
to the axial center of the rotating electric machine side shaft
in a surface of the rotor that faces the stator. The stator
has a magnetic flux generating area that faces each permanent
magnet in the axial direction.
More specifically, the stator includes a first stator
that has first teeth that form the magnetic flux generating
area, and a second stator that has second teeth that rotate
relatively with respect to the first teeth around the axial
center. The second teeth have a structure that allows a gap,
which generates magnetic resistance, between the second teeth
and the first teeth to be varied.
The first stator is fixed to the crank case, and the
second stator is provided with a driving mechanism that causes
the second stator to rotate relatively with respect to the first
stator.
The related engine with the attached axial gap type
rotating electric machine with the above-described structure
is mounted in a straddle-type vehicle, most typically a
motorcycle. Furthermore, the engine with the attached axial
gap type rotating electric machine can be used to run a
straddle-type vehicle. In this case, the axial gap type
rotating electric machine provides auxiliary drive for the
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crank shaft that is driven to rotate around the axial center
by the piston, or stops the rotation of the crank shaft caused
by the piston such that the crank shaft is just driven by the
axial gap type rotating electric machine.
However, in this engine with the attached axial gap type
rotating electric machine, a drive mechanism rotates the
second stator, thereby changing the gap that generates the
magnetic resistance between the first teeth and the second
teeth. As a result, the relationship of the rotational speed
and the rotational torque can be controlled. Accordingly, the
engine with the attached axial gap type rotating electric
machine can change the output characteristics of the axial gap
type rotating electric machine in accordance with the running
state of the straddle-type vehicle, for example, can change
to a high torque low speed mode or a low torque high speed mode.
However, in the related engine with the attached axial
gap type rotating electric machine, the axial gap type rotating
electric machine is connected to the crank shaft via a belt-type
continuously variable transmission, which makes reducing the
size of the engine with the attached axial gap type rotating
electric machine difficult. As a result, the engine with the
attached axial gap type rotating electric machine is more
difficult to mount in the straddle-type vehicle etc.
SUMMARY OF THE INVENTION
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The invention has been devised in light of the
above-described circumstances, and it is an object thereof to
provide an engine with an attached axial gap type rotating
electric machine that is extremely easy to mount.
An engine with an attached axial gap type rotating
electric machine of the invention includes: a crank case that
includes therein a crank shaft, the crank shaft being driven
to rotate around a center axis by a piston and being inserted
within the crank case such the crank shaft can rotate;
a rotor, fixed to one end side of the crank shaft at the
outside of the crank case, that includes a plurality of
permanent magnets that are orthogonal to the center axis; and
a stator, fixed to the crank case with the crank shaft
inserted therein, that has a magnetic flux generating area that
faces the permanent magnets in the axial direction. In this
engine with the attached axial gap type rotating electric
machine, the stator includes a first stator that has first-teeth
that form the magnetic flux generating area, and a second stator
that has second teeth. A gap between the first teeth and the
second teeth that generates magnetic resistance can be varied
by rotating the second teeth around the center axis relative
to the first teeth. The engine with the attached axial gap
type rotating electric machine further includes a drive
mechanism that relatively rotates either one or both of the
first stator and the second stator.
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In the engine with the attached axial gap type rotating
electric machine of the invention with the above-described
structure (hereinafter, "axial gap type rotating electric
machine" will be referred to simply as "rotating electric
machine") , the stator and the rotor are disposed on an extension
line of the center axis of the crank shaft. Thus, size
reduction as compared to the known technology can be promoted
in which the rotating electric machine is connected to the crank
shaft using a belt-type continuously variable transmission or
the like.
In addition, in the engine with attached rotating
electric machine, because the rotor is disposed further to the
outside than the stator, the fan that can blow air can be fixed
to the rotor and caused to rotate along with the rotor. Thus,
a structure is provided that makes it easier to cool the engine
with attached rotating electric machine while promoting size
reduction, and easier to cool a radiator that is disposed in
the vicinity of the engine with attached rotating electric
machine.
Accordingly, the engine with attached rotating electric
machine can be mounted extremely easily.
The manner in which the stator is fixed to the crank case
includes, in addition to directly fixing the stator to the crank
case, indirectly fixing the stator to the crank case via a cover
or the like that is included as a component of the crank case.
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In the engine with the attached rotating electric machine
of the invention, the drive mechanism may be attached to a
vehicle body frame or the like, or alternatively may be attached
to the crank case. If the latter structure is adopted, ease
of mounting is improved still further.
The manner in which the drive mechanism is attached to
the crank case includes, in addition to directly fixing the
drive mechanism to the crank case, indirectly fixing the drive
mechanism to the crank case via the cover or the like that is
included as a component of the crank case.
In the engine with attached rotating electric machine
of the invention, the rotor has a cup like shape and includes
a yoke that extends from the center axis in the radial direction,
and an outer cylindrical member, extending from an outer
periphery edge of the yoke toward the stator side, that covers,
at the least, a section of an outer periphery of the stator.
With this structure, the cup shaped rotor covers the gap between
the rotor and the stator, and thus it is difficult for foreign
objects like dirt or the like to enter in to the gap. Accordingly,
durability is substantially improved.
In the engine with attached rotating electric machine
of the invention, the permanent magnets may be embedded in the
rotor and arranged together. However, it is favorable that
the permanent magnets are arranged inside the rotor. If a
structure is adopted in which the permanent magnets are
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arranged inside the rotor, it is possible to reliably reduce
the size of the gap in the axial direction between the facing
permanent magnets and the magnetic flux generating area.
Accordingly, the engine with attached rotating electric
machine can fully demonstrate the performance of the rotating
electric machine.
The engine with attached rotating electric machine of
the invention may further include a gap adjustment mechanism,
provided between the crank case, the crank shaft, the rotor
and the stator, that determines a gap between the permanent
magnets and the magnetic flux generating area in the axial
direction. If this structure is adopted, the engine with
attached rotating electric machine is able to reliably reduce
the occurrence of variation in the gap in the axial direction
between the permanent magnets and the magnetic flux generating
area, thereby allowing the performance of the rotating
electric machine to be reliably demonstrated to an even higher
level.
In the engine with attached rotating electric machine
of the invention, the gap adjustment mechanism may include a
first regulation mechanism that regulates a position in the
axial direction of the crank shaft and the rotor, and a second
regulation mechanism that regulates a position in the axial
direction of the crank case and the stator while providing
tolerance for variation in the position in the axial direction
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of the crank shaft and the rotor. If this structure is adopted,
the engine with attached rotating electric machine is able to
reliably reduce the occurrence of variation in the gap in the
axial direction between the permanent magnets and the magnetic
flux generating area, thereby allowing the performance of the
rotating electric machine to be reliably demonstrated to an
even higher level.
In the engine with attached rotating electric machine
of the invention, the first regulation mechanism has a
structure in which one end of the crank shaft and the rotor
are fitted together using a tapered structure, and the second
regulation mechanism has a structure that includes a bearing
support member that is provided in an outer periphery surface
of a small diameter cylindrical member that protrudes from a
center of the rotor toward the stator side, a bearing support
member that is provided in an inner periphery surface of the
stator, a bearing that is provided between the bearing support
members, and an engagement pin and an engagement hole,
respectively provided in the stator and the crank case, that
provide tolerance for mutual movement in the axial direction.
If this structure is adopted, it is possible to reliably
reduce the occurrence of variation in the gap in the axial
direction between the permanent magnets and the magnetic flux
generating area. Note that, in a modified example of the first
regulation mechanism, the crank shaft and the rotor can be
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spline-engaged.
In the engine with attached rotating electric machine
of the invention, it is favorable if the first stator is fixed
to the crank case, and the second stator is rotatably provided
on the crank case. If this structure is adopted, in the engine
with attached rotating electric machine, there is no need to
rotate the first teeth, which have a structure that is more
complicated than the second teeth and that form the magnetic
flux generating area, and thus the device structure of the
engine can be simplified.
The engine with attached rotating electric machine of
the invention may further include: a fan that can blow wind
that is fixed to and integrated with the outside of the rotor.
Thus, the engine with attached rotating electric machine has
a structure that makes it easier to cool the engine with
attached rotating electric machine using the fan, and easier
to cool the radiator that is disposed in the vicinity of the
engine with attached rotating electric machine. In addition,
as a result of integrally fixing the fan to the rotor that is
lighter than the stator, rotational resistance is reduced.
In the engine with attached rotating electric machine
of the invention, the fan may intake air from the outside in
the axial direction, and blow out air to the outside in the
radial direction with respect to the center axis. If this
structure is adopted, a large intake port can be provided in
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the outside in the vehicle width direction of the straddle-type
vehicle or the like in which the engine with attached rotating
electric machine is mounted, thereby making it easier to intake
cool external air that has not been heated by the engine with
attached rotating electric machine, and to lead exhausted air
to the outside of the vehicle, such as a straddle-type vehicle.
The fan that intakes air from the outside in the axial
direction and that blows the air to the outside in the radial
direction with respect to the center axis may be a sirocco fan.
However, the fan is not limited to this, and may be a turbo
fan, or a combination of a sirocco fan and a turbo fan.
The engine with attached rotating electric machine of
the invention may further include: a radiator that is provided
in the crank case to the outside of the fan. If this structure
is adopted, the engine with attached rotating electric machine
can improve engine performance using water cooling. More
particularly, if the fan is of a type that intakes air from
the outside in the axial direction, cool external air can be
caused to hit the radiator, thereby effectively cooling the
radiator.
BRIEF DESCRIPTION OF THE DRAWINGS
FIG. 1 is side view of a motorcycle in which an engine
with an attached rotating electric machine of an embodiment
is mounted;
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FIG. 2 shows the engine with the attached rotating
electric machine of the embodiment in a side view of a rear
section of the motorcycle of FIG. 1;
FIG. 3 shows the engine with the attached rotating
electric machine of the embodiment along a cross section
III-III of FIG. 2;
FIG. 4 shows the engine with the attached rotating
electric machine of the embodiment, and is an expanded cross
sectional view of the rotating electric machine of the cross
sectional view of FIG. 3;
FIG. 5 shows the engine with the attached rotating
electric machine of the embodiment, and is an expanded cross
sectional view of a stator of the cross sectional view of FIG.
4;
FIG. 6 is a schematic outline view of a drive mechanism
of the engine with the attached rotating electric machine of
the embodiment;
FIG. 7 shows the engine with the attached rotating
electric machine of the embodiment and shows a state when a
moveable stator has rotated relative to a fixed stator;
FIG. 8 shows the engine with the attached rotating
electric machine of the embodiment, and shows a state when the
moveable stator has rotated relative to the fixed stator; and
FIG. 9 shows the engine with the attached rotating
electric machine of the embodiment, and shows a state when the
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moveable stator has rotated relative to the fixed stator.
DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS
Hereinafter, a concrete embodiment of the invention will
be described with reference to the drawings.
[Embodiments]
As can be seen from FIG. 1 to FIG. 4, an engine with an
attached axial gap type rotating electric machine 50
(hereinafter simply referred to as "engine with attached
rotating electric machine 50") of this embodiment is mounted
in a motorcycle 1.
The motorcycle 1, as shown in FIG. 1, is provided with
a front wheel 3 at a vehicle body front lower section. The
front wheel 3 is rotatably supported by a lower end section
of a front fork 5. A steering shaft 7 that extends upwards
is connected to an upper end section of the front fork 5. A
handle 9 that extends in the vehicle width direction is attached
to an upper end section of the steering shaft 7. Grips 11 are
attached to either end of the handle 9. A vehicle body frame
10 is attached to a central section of the steering shaft 7.
The vehicle body frame 10 extends diagonally downward
toward a vehicle body rear section, and then curves to extend
horizontally. Then, the vehicle body frame 10 curves again
before extending straight. A seat 13 is disposed on a rear
upper side of the vehicle body frame 10. An upper end section
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of a rear suspension 15 is connected to a rear end section of
the vehicle body frame 10.
As can be seen from FIG. 2, a lower end section of the
rear suspension 15 is connected to a rear end section 16a of
a rear arm 16 that is one section of the vehicle body frame
10. The rear arm 16 rotatably supports a rear wheel 17.
Driving force of the engine with attached rotating electric
machine 50 is transmitted to the rear wheel 17 via a drive force
transmission mechanism such as a belt-type continuously
variable transmission, thus rotatably driving the rear wheel
17. The engine with attached rotating electric machine 50 is
disposed beneath the central section of the vehicle body frame
10.
As shown in FIG. 3, the engine with attached rotating
electric machine 50 is provided with a crank case 60, a crank
shaft 51, and an axial gap type rotating electric machine 20
(hereinafter simply referred to as "rotating electric machine
20") .
The crank case 60 includes a crank case body 61, and a
crank case cover 62 that is positioned to the outside in the
vehicle width direction (the direction indicated by a shown
in FIG. 3) of the crank case body 61. The crank case cover
62 has a generally flat tabular shape. An engagement member
62b is formed in the crank case cover 62 in the inside in the
vehicle width direction (the direction opposite to that
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indicated by a in FIG. 3) . The engagement member 62b is fitted
in to an engaged member 61b that is formed in the outside in
the vehicle width direction of the crank case body 61. As a
result, the crank case cover 62 is assembled as an integrated
unit with the crank case body 61.
An insertion hole 61a that has a center axis that is
aligned with a center axis X of the crank shaft 51 is formed
in the outside in the vehicle width direction of the crank case
body 61. An insertion hole 62a that has a center axis that
is aligned with the center axis X is also formed in the crank
case cover 62.
The crank shaft 51 is disposed inside the crank case body
61, and is connected via a connecting rod 50c to a piston (not
shown in the figures) that is housed within a cylinder (not
shown in the figures) that is provided in a central section
of the engine with attached rotating electric machine 50. An
end section 51c to the outside in the vehicle width direction
of the crank shaft 51 extends through the insertion holes 61a,
62a, and protrudes further to the outside in the vehicle width
direction than the insertion hole 62a.
A bearing 52a that rotatably supports the crank shaft
51 such that it rotates around the center axis X is disposed
between the crank shaft 51 and the insertion hole 61a. In
addition, a bearing 52b that rotatably supports the crank shaft
51 such that it rotates around the center axis X is provided
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in the crank case body 61. As a result, the crank shaft 51
is driven to rotate around the center axis X inside the crank
case 60 by the up-down motion of the piston. Moreover, a seal
member 54 that seals a gap between the crank shaft 51 and the
crank case 60 is provided between the crank shaft 51 and the
insertion hole 62a.
The rotating electric machine 20 is disposed at the
outside in the vehicle width direction of the crank case 60.
The rotating electric machine 20 is provided with a rotor 21,
a stator 25, and a drive mechanism 80.
The rotor 21, as can be seen from FIG. 4, includes a small
diameter cylindrical member 22, a yoke 23, and an outer
cylindrical member 23a. An inner periphery surface of the
small diameter cylindrical member 22 is formed as a tapered
surface 22a that has a diameter that becomes smaller as the
tapered surface 22a extends toward the outside in the vehicle
width direction. On the other hand, an outer periphery surf ace
of the end section 51c of the crank shaft 51 is formed as a
tapered surface 51b that has a diameter that becomes smaller
as the tapered surface 51b extends toward the outside in the
vehicle width direction. Accordingly, when the small diameter
cylindrical member 22 of the rotor 21 is fitted to the end
section 51c of the crank shaft 51, the tapered surface 51b is
placed in contact with the tapered surface 22a. In addition,
a nut 57 is screwed on to a male screw formed in the end section
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51c. The nut 57 presses the rotor 21 toward the central section
of the crank shaft 51, whereby the tapered surface 51b and the
tapered surface 22a are held together under pressure. As a
result of adopting this structure, the rotor 21 is fixed to
the end section 51c side of the crank shaft 51, and the position
of the rotor 21 in the center axis X direction with respect
to the crank shaft 51 is determined.
The structure in which the end section 51c of the crank
shaft 51 and the rotor 21 are fitted together using tapered
surfaces, namely, using the tapered surface 51b and the tapered
surface 22a, corresponds to a first regulation mechanism that
regulates the position of the crank shaft 51 and the rotor 21
in the center axis X direction. In addition, with the first
regulation mechanism, there is a possibility that variation
in the position of the crank shaft 51 and the rotor 21 in the
center axis X direction may occur as a result of the
characteristics of the taper fit. However, a second
regulation mechanism described later is structured so as to
provide tolerance for such variation.
A groove 22h that extends in the center axis X direction
is formed in the tapered surface 22a of the small diameter
cylindrical member 22. On the other hand, a recess having a
semicircular shape is formed in the tapered surface 51b of the
end section 51c of the crank shaft 51. A key 22g with a
corresponding shape is fitted in to this recess. An edge of
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the key 22g protrudes from the tapered surface 51b, and engages
with the groove 22h. As a result of adopting this structure,
the key 22g is engaged with both the rotor 21 and the crank
shaft 51, thereby providing a structure in which the rotor 21
rotates along with the crank shaft 51.
The yoke 23 has a generally disk like shape that extends
from the small diameter cylindrical member 22 in the radial
direction. In addition, a plurality of permanent magnets 24
(field magnets) are fixed to the inside in the vehicle width
direction of the yoke 23, and are arranged in a circular manner
and orthogonal to the center axis X.
The outer cylindrical member 23a is a cylindrical body
that covers at least a section of the outer periphery of the
stator 25, described hereinafter, and extends toward the
inside in the vehicle width direction from an outer periphery
edge of the yoke 23. Due to providing the yoke 23 and the outer
cylindrical member 23a, the rotor has a cup like shape, and
thus a gap between the rotor 21 and the stator 25 is covered.
Accordingly, it is difficult for foreign objects like dirt or
the like to enter in to the gap between the rotor 21 and the
stator 25.
A cooling fan 65 that functions as a fan that can generate
air flow is integrally fixed by a bolt 65a to the outside in
the vehicle width direction of the yoke 23. The cooling fan
65 is a sirocco fan that is thin in the center axis X direction.
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The cooling fan 65 is formed by a plurality of integrated vanes
that can intake air from the outside in the center axis X
direction (outside in the vehicle width direction), and can
blow out the air to the outside in the radial direction with
respect to the center axis X.
As can be seen from FIG. 3, a radiator 66 is disposed
at the outside in the vehicle width direction of the cooling
fan 65. The radiator 66 is assembled together with a support
member (not shown in the figures) that extends toward the
outside in the vehicle width direction from the crank case 60.
A large intake port 66a is disposed at the outside in the vehicle
width direction of the radiator 66. Cool external air, which
enters via the intake port 66a from the outside in the vehicle
width direction as a result of rotation of the cooling fan 65,
directly hits the radiator 66. As a result, coolant that
circulates between the radiator 66 and a cylinder block (not
shown in the figures) of the engine 50 is effectively cooled.
In addition, a discharge port 66b is provided at the outside
in the radial direction of the cooling fan 65. Air that is
discharged from the cooling fan 65 to the outside in the radial
direction can be smoothly discharged to the outside of the
vehicle. Note that, hypothetically speaking, if the blow
direction of the cooling fan 65 is reversed, air that is warmed
by the heat of the engine with attached rotating electric
machine 50 hits the radiator 66, whereby cooling efficiency
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is lowered. However, the above-described structure
eliminates the possibility of this type of problem occurring.
The stator 25 is fixed to the outside in the vehicle width
direction of the crank case 60 with the crank shaft 51 inserted
therein. The stator 25 is disposed further to the inside in
the vehicle width direction than the rotor 21. In addition,
the stator 25 has an end surface (magnetic flux generating area)
34a that faces each of the permanent magnets 24 in the center
axis X direction.
More specifically, the stator 25 is provided with a fixed
stator 30 that functions as a first stator that is positioned
on the rotor 21 side, and a moveable stator 40 that functions
as a second stator that is positioned at the crank case cover
62 side.
As can be seen from FIG. 3 to FIG. 5, the fixed stator
30 is provided with a plurality of first teeth 34 formed by
magnetic cores. Each first tooth 34 is arranged in a ring like
shape that encircles the crank shaft 51. The end surface
(magnetic flux generating area) 34a of each first tooth 34 at
the rotor 21 side faces each permanent magnet 24 of the rotor
21.
A coil 31 that generates a magnetic flux when energized
is wound around each first tooth 34. The first teeth 34 and
the coil 31 are molded in to a resin member 36 that is made
from resin and that includes a lubricant. The resin member
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36 is formed in a ring like shape that centers on the center
axis X. As shown in the enlarge view of FIG. 5, the resin member
36 has an inner periphery section 36b that is generally
cylindrical and positioned at the inside in the diameter
direction of a coil group that is made up of a plurality of
coils 31. In addition, the resin member 36 has an outer
periphery section 36a that is generally cylindrical and
positioned at the outside in the diameter direction of the coil
group that is made up of the plurality of coils 31.
The outer periphery section 36a has a protrusion 36c that
extends toward the crank case cover 62 side (the inside in the
vehicle width direction). A plurality of engagement holes 37
are formed in an end surface of the protrusion 36c at the crank
case cover 62 side (the inside in the vehicle width direction)
and extend parallel with the center axis X. On the other hand,
a plurality of engagement pins 59 that protrude toward the
outside in the vehicle width direction are formed at positions
that correspond with the respective engagement holes 37 of the
crank case cover 62 such that the engagement pins 59 can fit
in to the respective engagement holes 37. In addition, each
engagement pin 59 is fitted in to each engagement hole 37 so
that the fixed stator 30 is fixed to the crank case cover 62
so as not to be capable of rotation around the center axis X.
The depth of each engagement hole 37 is made larger than the
protrusion length of each engagement pin 59. Therefore, the
20

relative position of each engagement hole 37 and each
engagement pin 59 is not restricted in the center axis X
direction.
A radial bearing 63 is disposed between an inner
periphery surface of the inner periphery section 36b and an
outer periphery surface of the small diameter cylindrical
member 22.
More particularly, a bearing support member 36i is
provided in the inner periphery surface of the inner periphery
section 36b. This bearing support member 36i includes a
bearing contact surface 36j and a bearing support surface 36c.
The bearing support surface 36c is formed to be perpendicular
to the center axis X, namely, faces the rotor 21. The bearing
support surface 36c is positioned in the vicinity of a center
point between an end section of the inner periphery section
36b at the rotor 21 side and an end section of the inner
periphery section 36b at the moveable stator 40 side. The
bearing contact surface 36j is formed to have a cylindrical
shape that centers on the center axis X, and contacts an outer
periphery surface 63a of the radial bearing 63.
In addition, a bearing support member 22e is formed at
an outer periphery side of the small diameter cylindrical
member 22. The bearing support member 22e includes a bearing
contact surface 22f and a bearing support surface 22d. The
bearing support surface 22d is formed to be perpendicular to
21

the center axis X, namely, faces the fixed stator 30. The
bearing support surface 22d is positioned in the vicinity of
a center point in the center axis X direction of the small
diameter cylindrical member 22. The bearing contact surface
22f is formed to have a cylindrical shape that centers on the
center axis X, and contacts an inner periphery surface 63b of
the radial bearing 63.
The radial bearing 63 is disposed between the bearing
support surface 36c and the bearing support surface 22d in the
center axis X direction. Note that, in the above explanation,
because the respective engagement holes 37 and the engagement
pins 59 do not have their respective relative positions in the
center axis X direction regulated, the fixed stator 30 is pulled
toward the rotor 21 side by magnetism of the permanent magnets
24. At this time, the bearing support surface 22d supports
the fixed stator 30 via the radial bearing 63 and the bearing
support surface 36c in resistance to the attracting force (the
magnetism). As a result, a gap h is maintained between the
facing surface 24a of each permanent magnet 24 that faces the
fixed stator 30 and the end surfaces (the magnetic flux
generating area) 34a of the first teeth 34 that face the
permanent magnets 24. Note that, the gap h is more specifically
the gap between each permanent magnet 24 and the end surfaces
(the magnetic flux generating area) 34a in the center axis X
direction. The gap h can be determined by the position of the
22

bearing support surface 36c of the fixed stator 30, the width
of the radial bearing 63 in the center axis X direction, and
the position of the bearing support surface 22d of the small
diameter cylindrical member 22.
In addition, the radial bearing 63 is in contact with
both the bearing contact surface 36j of the fixed stator 30
and the bearing contact surface 22f of the small diameter
cylindrical member 22 . Thus, the radial bearing 63 can provide
support such that relative rotation is possible, without
causing diameter direction misalignment of the fixed stator
30 or the rotor 21.
The radial bearing 63, the bearing support member 36i
of the fixed stator 30, the bearing support member 22e of the
small diameter cylindrical member 22, the engagement holes 37,
and the engagement pins 59 correspond to a second regulation
mechanism that permits variation in the position in the center
axis X direction of the crank shaft 51 and the rotor 21, but
regulates the position in the center axis X direction of the
crank case 60 and the stator 25. In addition, the second
regulation mechanism and the above-described first regulation
mechanism form a gap adjustment mechanism that determines the
gap h in the center axis X direction between the permanent
magnets 24 and the end surfaces (magnetic flux generating area)
34a.
Next, the moveable stator 40 will be explained. The
23

moveable stator 40, as described above, is disposed further
to the crank case cover 62 side than the fixed stator 30 with
respect to the rotor 21, and faces the fixed stator 30.
The moveable stator 40 is provided with second teeth 41,
and a ring shaped base 42. The number of provided second teeth
41 is the same as the first teeth 34. The base 42 supports
the second teeth 41 that are arranged in a ring like shape
centering on the center axis X. The base 42 and the second
teeth 41 are molded in to a resin member 43 that is made from
resin and that includes a lubricant. Each second tooth 41 is
formed by a magnetic core. Magnetism generation by
energization of the coil 31 exerts a force that pulls the second
teeth 41 toward the first teeth 34 side. However, a holding
member (not shown in the figures) holds the second teeth 41
such that there is a determined distance of separation from
the first teeth 34 in the center axis X direction. In addition,
the moveable stator 40, as described below, is capable of
relative rotation with respect to the fixed stator 30 around
the center axis X direction.
The drive mechanism 80, as can be seen from FIG. 4 and
FIG. 6, is disposed at the outside in the vehicle width
direction of the crank case cover 62, and to the outside in
the diameter direction of the moveable stator 40. The drive
mechanism 80 includes a drive motor 81 and the gear mechanism
82. The gear mechanism 82 includes a worm gear 82a, a worm
24

wheel 82b, and a missing tooth gear 82c. When the drive motor
81 rotates, as shown in FIG. 6, the worm wheel 82b rotates within
a determined angular range, and driving force is transmitted
to a missing tooth gear 82d that is formed on a section of the
outer periphery surface of the moveable stator 40 via the
missing tooth gear 82c. As a result, in the drive mechanism
80, when the drive motor 81 rotates in the forward or reverse
direction, the moveable stator 40 turns around the center axis
X, and rotates relative to the fixed stator 30.
In the rotating electric machine 20 with the
above-described structure, relative rotation of the moveable
stator 40 and the fixed stator 30 causes change in output
characteristics as described below. Thus drive can be
performed at high torque low speed or at low torque high speed.
FIG. 7 to FIG. 9 show different states when the moveable
stator 40 is relatively rotated with respect to the fixed stator
30 around the center axis X. Note that, for the sake of
explanatory simplicity, illustrations of the resin member 36
of the fixed stator 30 shown in FIG. 3 to FIG. 5, the resin
member 43 of the moveable stator 40, the crank shaft 51, and
the coil 31 etc. are omitted. In addition, in FIG. 7 to FIG.
9, the same members as shown in FIG. 3 to FIG. 5 are denoted
with the same reference numerals.
FIG. 7 shows a state when the second teeth 41 of the
moveable stator 40 are aligned with the first teeth 34 of the
25

fixed stator 30. In this state, the gap, which generates
magnetic resistance, between the end surface 34b at the second
teeth 41 side of the first teeth 34 and the end surface 41a
at the first teeth 34 side of the second teeth 41 is at its
smallest value k (refer to FIG. 5). At this time, magnetic
flux flow is generated in the first teeth 34 and the second
teeth 41, the base 42, and each permanent magnet 24. This
magnetic flux flow flows from the end surface 34a of the first
teeth 34 at the permanent magnets 24 side to the end surface
34b on the opposite side. In other words, in this state, the
magnetic flux flow flows within the coil 31.
When drive of the drive mechanism 80 causes the moveable
stator 40 to rotate through the intermediate position shown
in FIG. 8 to the position shown in FIG. 9, namely, where the
second teeth 41 has rotated to a center position between the
first teeth 34 and neighboring first teeth 34, the gap, which
generates magnetic resistance, between the end surface 34b at
the second teeth 41 side of the first teeth 34 and the end
surface 41a at the first teeth 34 side of the second teeth 41
becomes larger. At this time, the magnetic flux flow does not
flow in the second teeth 41, and a magnetic flux flow flows
in the permanent magnets 24 and the first teeth 34 in the
vicinity of the rotor 21. This magnetic flux flow does not
flow inside the coil 31, and thus as compared to the state shown
in FIG. 7, the magnetic flux flow is weak. In the state shown
26

in FIG. 9, because the magnetic flux flow is weak, the rotating
electric machine 20 functions as a rotating electric machine
of a low torque high speed type. On the other hand, in the
state shown in FIG. 7, the magnetic flux flow is stronger than
that shown in FIG. 9, because it flows inside the coil 31, and
the rotating electric machine 20 functions as a rotating
electric machine of a high torque low speed type.
The engine with attached rotating electric machine 50
of this embodiment with the above-described structure can use
the rotating electric machine 20 to provide auxiliary drive
for the crank shaft 51 that is caused to rotate around the center
axis X by the piston. In addition, the engine with attached
rotating electric machine 50 can stop the rotation of the crank
shaft 51 caused by the piston, and use just the drive of the
rotating electric machine 20 to run the motorcycle 1.
Note that, in the engine with attached rotating electric
machine 50 of this embodiment, the stator 25 and the rotor 21
are disposed on an extension line of the center axis X of the
crank shaft 51. Thus, size reduction as compared to the known
technology can be promoted in which the rotating electric
machine is connected to the crank shaft using a belt-type
continuously variable transmission or the like.
In addition, in the engine with attached rotating
electric machine 50, because the rotor 21 is disposed further
to the outside in the vehicle width direction than the stator
27

25, the cooling fan 65 can be fixed to the rotor 21 and caused
to rotate along with the rotor 21. Thus, a structure is
provided that makes it easier to cool the engine with attached
rotating electric machine 50 while promoting size reduction,
and easier to cool the radiator 66 that is disposed to the
outside in the vehicle width direction of the engine with
attached rotating electric machine 50.
Accordingly, the engine with attached rotating electric
machine 50 is extremely easy to mount.
Moreover, the engine with attached rotating electric
machine 50 has a structure in which the drive mechanism 80 is
attached to the crank case 60, and thus ease of mounting is
improved still further.
In addition, in the engine with attached rotating
electric machine 50, the cap shaped rotor 21 covers the gap
between the rotor 21 and the stator 25, and thus it is difficult
for foreign objects like dirt or the like to enter in to the
gap. Accordingly, durability is substantially improved.
Furthermore, the engine with attached rotating electric
machine 50 has a structure in which the permanent magnets 24
are arranged inside the rotor 21, and thus it is possible to
reliably reduce the size of the gap h in the center axis X
direction between the facing permanent magnets 24 and the
magnetic flux generating area 34a. Accordingly, the
performance of the rotating electric machine 20 can be fully
28

demonstrated.
In addition, in the engine with attached rotating
electric machine 50, the gap adjustment mechanism formed by
the above-described first regulation mechanism and the second
regulation mechanism is provided between the crank case 60,
the crank shaft 51, the rotor 21, and the stator 25. Thus, it
is possible to reliably reduce the occurrence of variation in
the gap h in the center axis X direction between the permanent
magnets 24 and the magnetic flux generating area 34a, thereby
allowing the performance of the rotating electric machine 20
to be reliably demonstrated to an even higher level.
In addition, in the engine with attached rotating
electric machine 50, the fixed stator 30, which has a structure
that is more complicated than the moveable stator 40, is fixed
to the crank case 60, and thus the moveable stator 40 can be
provided so as to be rotatable with respect to the crank case
60. Accordingly, the device structure of the engine with
attached rotating electric machine 50 is simplified.
Furthermore, in the engine with attached rotating
electric machine 50, the cooling fan 65 is fixed in an
integrated manner at the outside in the vehicle width direction
of the rotor 21. Thus, the engine with attached rotating
electric machine 50 has a structure that makes it easier to
cool the engine with attached rotating electric machine 50
using the cooling fan 65, and easier to cool the radiator 66
29

that is disposed to the outside in the vehicle width direction
of the engine with attached rotating electric machine 50. In
addition, as a result of integrally fixing the cooling fan 65
to the rotor 21 that is lighter than the stator 25, rotational
resistance is reduced.
Moreover, in the engine with attached rotating electric
machine 50, the cooling fan 65 intakes air from the vehicle
width direction side, and blows out air to the outside in the
radial direction with respect to the center axis X. Thus, the
large intake port 66a can be provided in the outside in the
vehicle width direction of the motorcycle 1 in which the engine
with attached rotating electric machine 50 is mounted, thereby
making it easier to intake cool external air and to lead
exhausted air to the outside of the motorcycle 1.
In addition, in the engine with attached rotating
electric machine 50, the radiator 66 is provided at the outside
of the cooling fan 65 in the crank case 60. Moreover, the cool
external air that is sucked in from the outside in the vehicle
width direction by the cooling fan 65 directly hits the radiator
66, thereby improving the cooling effect and improving engine
performance.
Hereinabove, an embodiment of the invention is described.
However, the invention is not limited to this embodiment, and
can be modified and applied as appropriate within the range
implied by the spirit of the invention.
30

[Industrial Applicability]
The invention can be used as an engine with an attached
axial gap type rotating electric machine.
31

WE CLAIM:
1. An engine with an attached axial gap type rotating
electric machine, comprising:
a crank case that includes therein a crank shaft, the
crank shaft being driven to rotate around a center axis by a
piston and being inserted within the crank case such the crank
shaft can rotate;
a rotor, fixed to one end side of the crank shaft at the
outside of the crank case, that includes a plurality of
permanent magnets that are orthogonal to the center axis; and
a stator, fixed to the crank case with the crank shaft
inserted therein, that has a magnetic flux generating area that
faces the permanent magnets in the axial direction,
wherein the stator includes:
a first stator that has first teeth that form the
magnetic flux generating area; and
a second stator that has second teeth, wherein a
gap between the first teeth and the second teeth that generates
magnetic resistance can be varied by rotating the second teeth
around the center axis relative to the first teeth, and
wherein the engine with the attached axial gap type
rotating electric machine further comprises:
a drive mechanism that relatively rotates either one or
both of the first stator and the second stator.
32

2. The engine with the attached axial gap type
rotating electric machine as claimed in claim 1, wherein the
drive mechanism is attached to the crank case.
3. The engine with the attached axial gap type
rotating electric machine as claimed in either claim 1 or claim
2, wherein the rotor has a cup like shape and includes a yoke
that extends from the center axis in the radial direction, and
an outer cylindrical member, extending from an outer periphery
edge of the yoke toward the stator side, that covers, at the
least, a section of an outer periphery of the stator.
4. The engine with the attached axial gap type
rotating electric machine as claimed in claim 3, wherein each
of the permanent magnets is disposed inside the rotor.
5. The engine with the attached axial gap type
rotating electric machine as claimed in claim 1, further
comprising: a gap adjustment mechanism, provided between the
crank case, the crank shaft, the rotor and the stator, that
determines a gap between the permanent magnets and the magnetic
flux generating area in the axial direction.
6. The engine with the attached axial gap type
rotating electric machine as claimed in claim 5, wherein the
33

gap adjustment mechanism includes a first regulation mechanism
that regulates a position in the axial direction of the crank
shaft and the rotor, and a second regulation mechanism that
regulates a position in the axial direction of the crank case
and the stator while providing tolerance for variation in the
position in the axial direction of the crank shaft and the
rotor.
7. The engine with the attached axial gap type
rotating electric machine as claimed in claim 6,
wherein the first regulation mechanism has a structure
in which one end of the crank shaft and the rotor are fitted
together using a tapered structure, and
wherein the second regulation mechanism has a structure
that includes:
a bearing support member that is provided in an
outer periphery surface of a small diameter cylindrical member
that protrudes from a center of the rotor toward the stator
side;
a bearing support member that is provided in an
inner periphery surface of the stator;
a bearing that is provided between the bearing
support members; and
an engagement pin and an engagement hole,
respectively provided in the stator and the crank case, that
34

provide tolerance for mutual movement in the axial direction.
8. The engine with the attached axial gap type
rotating electric machine as claimed in claim 1,
wherein the first stator is fixed to the crank case, and
wherein the second stator is rotatably provided on the
crank case.
9. The engine with the attached axial gap type
rotating electric machine as claimed in claim 1, further
comprising:
a fan that can blow wind that is fixed to and integrated
with the outside of the rotor.
10. The engine with the attached axial gap type
rotating electric machine as claimed in claim 9, wherein the
fan intakes air from the outside in the axial direction, and
blows out air to the outside in the radial direction with
respect to the center axis.
11. The engine with the attached axial gap type
rotating electric machine as claimed in claim 9 or claim 10,
further comprising:
a radiator that is provided in the crank case to the
outside of the fan.

An engine with the attached axial gap type rotating electric machine includes a crank case, a rotor, and a stator. A crank shaft, that is driven to rotate around a center axis by a piston, is inserted within the crank case such the crank shaft can rotate. The rotor is fixed to an end section side of the crank shaft at the outside of the crank case, and includes
a plurality of permanent magnets. The stator is fixed to the crank case with the crank shaft inserted therein, and faces the permanent magnets in the center axis direction. The stator
includes a fixed stator that has first teeth, and a moveable stator that has second teeth. A gap between the first teeth and the second teeth that generates magnetic resistance can
be varied by rotating the second teeth around the center axis relative to the first teeth. A drive mechanism is provided that relatively rotates the first stator and the second stator.

Documents:

00144-kol-2008-abstract.pdf

00144-kol-2008-claims.pdf

00144-kol-2008-correspondence others.pdf

00144-kol-2008-description complete.pdf

00144-kol-2008-drawings.pdf

00144-kol-2008-form 1.pdf

00144-kol-2008-form 2.pdf

00144-kol-2008-form 3.pdf

00144-kol-2008-form 5.pdf

144-KOL-2008-(21-06-2013)-ABSTRACT.pdf

144-KOL-2008-(21-06-2013)-ANNEXURE TO FORM 3.pdf

144-KOL-2008-(21-06-2013)-CLAIMS.pdf

144-KOL-2008-(21-06-2013)-CORRESPONDENCE.pdf

144-KOL-2008-(21-06-2013)-OTHERS.pdf

144-KOL-2008-(21-06-2013)-PA.pdf

144-KOL-2008-CORRESPONDENCE OTHERS 1.1.pdf

144-KOL-2008-CORRESPONDENCE OTHERS 1.2.pdf

144-KOL-2008-CORRESPONDENCE.pdf

144-KOL-2008-EXAMINATION REPORT.pdf

144-KOL-2008-FORM 18-1.1.pdf

144-kol-2008-form 18.pdf

144-KOL-2008-GPA.pdf

144-KOL-2008-GRANTED-ABSTRACT.pdf

144-KOL-2008-GRANTED-CLAIMS.pdf

144-KOL-2008-GRANTED-DESCRIPTION (COMPLETE).pdf

144-KOL-2008-GRANTED-DRAWINGS.pdf

144-KOL-2008-GRANTED-FORM 1.pdf

144-KOL-2008-GRANTED-FORM 2.pdf

144-KOL-2008-GRANTED-FORM 3.pdf

144-KOL-2008-GRANTED-FORM 5.pdf

144-KOL-2008-GRANTED-SPECIFICATION-COMPLETE.pdf

144-KOL-2008-OTHERS-1.1.pdf

144-KOL-2008-OTHERS.pdf

144-KOL-2008-PETITION UNDER RULE 137.pdf

144-KOL-2008-PRIORITY DOCUMENT-1.1.pdf

144-KOL-2008-PRIORITY DOCUMENT.pdf

144-KOL-2008-REPLY TO EXAMINATION REPORT.pdf

144-KOL-2008-TRANSLATED COPY OF PRIORITY DOCUMENT-1.1.pdf

144-KOL-2008-TRANSLATED COPY OF PRIORITY DOCUMENT.pdf


Patent Number 259449
Indian Patent Application Number 144/KOL/2008
PG Journal Number 11/2014
Publication Date 14-Mar-2014
Grant Date 12-Mar-2014
Date of Filing 23-Jan-2008
Name of Patentee YAMAHA HATSUDOKI KABUSHIKI KAISHA
Applicant Address 2500, SHINGAI, IWATA-SHI, SHIZUOKA-KEN
Inventors:
# Inventor's Name Inventor's Address
1 HIROYUKI KAMINOKADO C/O. YAMAHA HATSUDOKI KABUSHIKI KAISHA, 2500, SHINGAI, IWATA-SHI, SHIZUOKA 4388501,JAPAN
PCT International Classification Number H02G3/30; H02K5/22
PCT International Application Number N/A
PCT International Filing date
PCT Conventions:
# PCT Application Number Date of Convention Priority Country
1 2007-026941 2007-02-06 Japan