Information
-
Patent Grant
-
6729294
-
Patent Number
6,729,294
-
Date Filed
Friday, August 9, 200222 years ago
-
Date Issued
Tuesday, May 4, 200420 years ago
-
Inventors
-
Original Assignees
-
Examiners
Agents
- Birch, Stewart, Kolasch & Birch, LLP
-
CPC
-
US Classifications
Field of Search
-
International Classifications
-
Abstract
In a V-type engine for a motorcycle in which both banks are arranged in a V-shape in a plane orthogonal to the axis of a crankshaft and the heights of both the banks are different from each other, the heights of the pair of banks are visually recognized to be almost equal to enhance the functional beauty of the engine and improve the marketability. A plurality of fins are aligned in the direction along cylinder axes and are provided on sides of cylinders and on sides of dummy covers for covering at least part of cylinder heads from the sides. Wherein the total number and center line mutual distances of the fins are almost equal in both banks. Lengths between the center lines of the fins closest to a crankshaft of the fins and a cross point of the cylinder axes are set to be almost equal in both the banks.
Description
BACKGROUND OF THE INVENTION
CROSS-REFERENCE TO RELATED APPLICATIONS
The present application claims priority under 35 USC 119 to Japanese Patent Application No. 2001-273597 filed on Sep. 10, 2001 the entire contents thereof is hereby incorporated by reference.
1. Field of the Invention
The present invention relates to a V-type engine for a motorcycle in which a first bank having a first cylinder coupled to a first cylinder head and a second bank having a second cylinder coupled to a second cylinder head are arranged in a V-shape in a plane orthogonal to the axis of a crankshaft. A length between a cross point at which cylinder axes of the first and second cylinders cross each other in the plane and a deck surface of the first cylinder head and a length between said cross point and a deck surface of the second cylinder head are set to be different relative to each other.
2. Description of Background Art
A V-type engine for a motorcycle is disclosed in Japanese Published Unexamined Patent Application No. Sho 60-53625. To set a nip angle of a pair of banks to a minimum, a cross point of cylinder axes of a pair of banks is arranged in a position offset from the axis of a crankshaft and the lengths between the cross point and deck surfaces of the cylinders of both the banks are set to be different relative to each other. In this disclosure, the lengths between the cross point and the deck surfaces of the cylinder heads of both the banks are considered to be essentially different relative to each other.
In a motorcycle, particularly, a custom-type motorcycle, the functional beauty (functional appearance) of the mounting of an engine occupies an important position. As described above, the lengths between the deck surfaces of the cylinder heads of a pair of banks and a cross point of cylinder axes of both the banks are different for both of the banks. A difference in height between both the banks is significantly visual. A feeling of unbalance may be produced to deteriorate the functional beauty. In particular, in a V-type engine having a nip angle below 90° which is mounted on a custom-type motorcycle in many cases, the height of both the banks is easily compared visually so that the unbalance feeling is easily emphasized.
SUMMARY AND OBJECTS OF THE INVENTION
The present invention has been made in view of such circumstances and it is an object of the present invention is to provide a V-type engine for a motorcycle which enhances the functional beauty of the engine and improves the marketability so that the height of a pair of banks is visually recognized to be almost equal.
To achieve the foregoing object, in the present invention, a V-type engine for a motorcycle including a first bank having a first cylinder coupled to a first cylinder head and a second bank having a second cylinder coupled to a second cylinder head are arranged in a V-shape in a plane orthogonal to the axis of a crankshaft. A length between a cross point at which cylinder axes of the first and second cylinders cross each other in the plane and a deck surface of the first cylinder head and a length between the cross point and a deck surface of the second cylinder head are set to be different from each other. In the sides of the first and second cylinders or the sides of dummy covers for covering at least part of the first and second cylinders from the sides and in the sides of the first and second cylinder heads or the sides of the dummy covers for covering at least part of the first and second cylinder heads from the sides, a plurality of fins are aligned in the direction along the cylinder axes of the first and second cylinders that are provided so that the total numbers of the fins and center line mutual distances of the fins are almost equal in the first and second banks. The lengths in the plane between the center lines of the fins closest to the crankshaft of the fins and the cross point are set to be almost equal in the first and second banks.
In such a construction according to the present invention, the heights of a pair of the banks are visually recognized to be almost equal to enhance the functional beauty of the engine. A plurality of fins are provided on the sides of the cylinders and the cylinder heads for the purpose of cooling or a plurality of fins are provided in the sides of the dummy covers for covering at least part of the cylinders and the cylinder heads from the sides for enhancing the appearance and having a function to decide the appearance shape of both the banks. The total numbers of a plurality of the fins aligned in the direction along the cylinder axes of the first and second cylinders and the center line mutual distances of the fins are almost equal in the first and second banks. The lengths of the center lines of the fins closest to the crankshaft of the fins and the cross point of both the cylinder axes are set to be almost equal in the first and second banks. The fins of both the banks are arranged to correspond to almost the same position along the cylinder axes of the banks. Thus, a visual impression without any difference in height between the pair of banks can be obtained. The present invention provides for a functional beauty of the V-type engine to be enhanced. The marketability of the V-type engine is thus improved.
In the present invention, the contour shapes including the fins of the first and second cylinders or the dummy covers for covering at least part of the first and second cylinders from the sides and the first and second cylinder heads or the dummy covers for covering at least part of the first and second cylinder heads from the sides are formed almost symmetrically with respect to a plane including a bisector between both the banks passing though the cross point in the side view in the direction along the axis of the crankshaft. According to such a construction, the contour shapes of the first and second banks are shaped almost symmetrically. The functional beauty of the V-type engine can be enhanced. The marketability can be improved.
In the present invention the lengths between cross points at which first and second head covers are coupled to the first and second cylinder heads or first and second overhead covers are provided for covering at least part of the first and second head covers from above and the sides cross the cylinder axes of the first and second cylinders in the plane and the cross point at which the cylinder axes of the first and second cylinders cross each other in the plane are set to be almost equal in the first and second banks. According to such a construction, the height difference and the appearance shape difference between both the banks appear to be smaller. The functional beauty of the V-type engine can be enhanced. Thus, the marketability can be improved.
Further scope of applicability of the present invention will become apparent from the detailed description given hereinafter. However, it should be understood that the detailed description and specific examples, while indicating preferred embodiments of the invention, are given by way of illustration only, since various changes and modifications within the spirit and scope of the invention will become apparent to those skilled in the art from this detailed description.
BRIEF DESCRIPTION OF THE DRAWINGS
The present invention will become more fully understood from the detailed description given hereinbelow and the accompanying drawings which are given by way of illustration only, and thus are not limitative of the present invention, and wherein:
FIG. 1
is a right side view of a motorcycle;
FIG. 2
is a side view of a power unit viewed from the right side of the motorcycle;
FIG. 3
is a partially cutaway longitudinal side view of the power unit viewed from the left side of the motorcycle;
FIG. 4
is an enlarged cross-sectional view taken along line
4
—
4
of
FIG. 3
;
FIG. 5
is a left side view of a right-side dummy cover;
FIG. 6
is a cross-sectional view taken along line
6
—
6
of
FIG. 5
;
FIG. 7
is a cross-sectional view taken along line
7
—
7
of
FIG. 5
;
FIG. 8
is a right side view of a left-side dummy cover;
FIG. 9
is a cross-sectional view taken along line
9
—
9
of
FIG. 8
;
FIG. 10
is a cross-sectional view taken along line
10
—
10
of
FIG. 8
;
FIG. 11
is a right side view of a right-side overhead cover;
FIG. 12
is a diagram of arrow
12
of
FIG. 11
;
FIG. 13
is a diagram of arrow
13
of
FIG. 11
;
FIG. 14
is a left side view of a left-side overhead cover;
FIG. 15
is a diagram of arrow
15
of
FIG. 14
;
FIG. 16
is a diagram of arrow
16
of
FIG. 14
; and
FIG. 17
is an enlarged side view of portions on a crankcase side of a first and a second cylinders viewed from the left side of the motorcycle.
DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS
An embodiment of the present invention shown in the accompanying drawings will be described hereinbelow.
FIGS. 1
to
17
show an embodiment of the present invention. In the following description, “left,” “right,” “front,” “rear,” “up” and “down” are referred to with reference to the body of a motorcycle.
In
FIG. 1
, in a head pipe
22
provided at the front end of a body frame
21
of a custom-type motorcycle, a front fork
23
for supporting a front wheel WF is supported steerably. The upper end of the front fork
23
is coupled to a steering wheel
24
. The rear portion of the body frame
21
is coupled to a rear fork
25
for supporting a rear wheel WR so as to be swingable upwardly or downwardly. A rear cushion
26
is interposed between the rear fork
25
and the body frame
21
.
A fuel tank
27
is mounted on the body frame
21
rearwardly of the head pipe
22
. A tandem-type riding seat
28
is provided on the body frame
21
rearwardly of the fuel tank
27
.
A power unit P mounted on the body frame
21
is arranged below the fuel tank
27
. The power unit P has a two-cylinder engine E and a transmission M for shifting the rotating power of the engine E which is then transmitted to the rear wheel WR.
Referring to
FIGS. 2 and 3
, the engine E is a V-type engine in which a first bank BA and a second bank BB, which is arranged rearwardly of the first bank BA, are arranged in a V-shape in a plane orthogonal to the axis of a crankshaft
30
having an axis extending horizontally in the right and left directions of the body frame
21
. The crankshaft
30
is rotatably supported in a crankcase
31
serving as a transmission case of the transmission M.
An engine main unit
32
of the engine E includes the crankcase
31
, a first cylinder
33
A coupled to the crankcase
31
with a second cylinder
33
B coupled to the crankcase
31
rearwardly of the first cylinder
33
A. A first cylinder head
34
A is coupled to the first cylinder
33
A with a second cylinder head
34
B coupled to the second cylinder
33
B. A first head cover
35
A is coupled to the first cylinder head
34
A, and a second head cover
35
B is coupled to the second cylinder head
34
B.
The first bank BA has the first cylinder
33
A and the first cylinder head
34
A coupled to each other. The second bank BB has the first cylinder
33
B and the second cylinder head
34
B coupled to each other and is arranged rearwardly of the first bank BA.
Pistons
37
A,
37
B are slidably disposed in the cylinder bores
36
A,
36
B provided in the first and second cylinders
33
A,
33
B and are coupled to the crankshaft
30
via connecting rods
38
A,
38
B.
The engine E is a water-cooled engine. A first cooling water jacket
31
A is formed in the first cylinder
33
A and the first cylinder head
34
A of the first bank BA. A second cooling water jacket
31
B is formed in the second cylinder
33
B and the second cylinder head
34
B of the second bank BB. Originally, cooling fins required in an air-cooled engine are not needed to be provided adjacent to the sides of the first and second cylinders
33
A,
33
B. To enhance the functional beauty (functional appearance) of the engine E, the first cylinder
33
A is provided with a plurality of fins
40
A . . . along its sides aligned in the direction along a cylinder axis CA of the first cylinder
33
A. The second cylinder
33
B is provided with a plurality of fins
40
B . . . along its sides in a number equal to the fins
40
A . . . of the first cylinder
33
A aligned in the direction along a cylinder axis CB of the second cylinder
33
B.
Referring to
FIG. 4
, the right sides of the first cylinder head
34
A and the first head cover
35
A are covered by a right-side first dummy cover
42
A. The left sides of the first cylinder head
34
A and the first head cover
35
A are covered by a left-side first dummy cover
43
A. These dummy covers
42
A,
43
A are intended for enhancing the functional beauty of the engine E and are made of metal to eliminate heat and to enhance the functional beauty. An equal plurality of fins
44
A . . . ,
45
A . . . as dummy cooling fins are provided in the sides of the dummy covers
42
A,
43
A, respectively.
In
FIGS. 5
to
7
, in the upper portion of the right-side first dummy cover
42
A, at least one cylindrical resilient member
46
(a pair of cylindrical resilient members
46
,
46
in this embodiment) is provided. In the right side of the first head cover
35
A as part of the engine main unit
32
, bosses
47
. . . corresponding to the resilient members
46
,
46
protrudes outwardly. Bolts
41
. . . extending through metal sleeves
48
. . . inserted into the resilient members
46
,
46
are threadedly engaged with the bosses
47
. . . . At least one spot (two spots in this embodiment) of the right-side first dummy cover
42
A is fastened to the first head cover
35
A as part of the engine main unit
32
with the bolts
41
. . . .
On the first cylinder head
34
A, a pair of spark plugs
51
,
52
facing a combustion chamber
50
are mounted. A notch
53
for arranging the one spark plug
51
is provided in the right-side first dummy cover
42
A. The fins
44
A . . . avoid the notch
53
and are provided on the side of the right-side first dummy cover
42
A.
At least one projection
54
(a pair of projections
54
,
54
in this embodiment) protrude in the lower portion of the right-side first dummy cover
42
A. In the first cylinder
33
A in a portion corresponding to the fin
40
A closest to the first cylinder head
34
A of the fins
40
A . . . in the first cylinder
33
A, that is, the uppermost fin
40
A, metal cylindrical members
56
. . . are buried corresponding to the projections
54
. . . . The projections
54
. . . are fitted in recesses
55
. . . provided in the first cylinder
33
A so as to be constructed by the cylindrical members
56
. . . and the first cylinder
33
A.
In
FIGS. 8
to
10
, in the upper portion of the left-side first dummy cover
43
A, at least one cylindrical resilient member
57
(a pair of cylindrical resilient members
57
,
57
in this embodiment) is provided. In the left side of the first head cover
35
A as part of the engine main unit
32
, bosses
58
. . . corresponding to the resilient members
57
,
57
protrude outwardly. Bolts
60
. . . extending through metal sleeves
51
. . . inserted into the resilient members
57
,
57
are threadedly engaged with the bosses
58
. . . . At least one spot (two spots in this embodiment) of the left-side first dummy cover
43
A is fastened to the first head cover
35
A as part of the engine main unit
32
with the bolts
60
. . . .
A notch
83
for arranging the other spark plug
52
of the pair of spark plugs
51
,
52
facing the combustion chamber
50
is provided in the left-side first dummy cover
43
A. Fins
44
B . . . avoid the notch
83
and are provided in the side of the left-side first dummy cover
43
A.
At least one projection
61
(a pair of projections
61
,
61
in this embodiment) protrudes in the lower portion of the left-side first dummy cover
43
A. In the first cylinder
33
A in a portion corresponding to the fin
40
A closest to the first cylinder head
34
A of the fins
40
A . . . in the first cylinder
33
A, that is, the uppermost fin
40
A, metal cylindrical members
63
. . . are buried corresponding to the projections
61
. . . . The projections
61
. . . are fitted in recesses
62
. . . provided in the first cylinder
33
A so as to be constructed by the cylindrical members
63
. . . and the first cylinder
33
A.
At least part of the first head cover
35
A coupled to the first cylinder head
34
A (the right and left sides of the first head cover
35
A in this embodiment) is covered by a right-side first overhead cover
64
A and a left-side first overhead cover
65
A.
In
FIGS. 11
to
13
, the right-side first overhead cover
64
A is formed of synthetic resin so as to cover the right side of the first head cover
35
A from above and the sides and is mounted on the right-side first dummy cover
42
A so as to be detachable or attachable.
The right-side first overhead cover
64
A has the side view formed in a substantially T shape so as to cover the bolts
41
. . . for mounting the right-side first dummy cover
42
A on the first head cover
35
A and the notch
53
provided in the right-side first dummy cover
42
A to arrange the spark plug
51
when mounted to the right-side first dummy cover
42
A.
In the upper portion of the right-side first overhead cover
64
A, a pair of engaging projections
66
,
66
protrudes to the right-side first dummy cover
42
A side protrude. In the lower portion of the right-side first overhead cover
64
A in the middle position between the engaging projections
66
,
66
, an engaging projection
67
protruding to the right-side first dummy cover
42
A side.
In the right-side first dummy cover
42
A, cylindrical engaging members
68
,
68
made of synthetic resin are provided corresponding to both the engaging projections
66
,
66
and the cylindrical engaging member
61
made of synthetic resin is provided corresponding to the engaging projection
67
. The engaging projections
66
,
66
,
67
inserted into the engaging members
68
,
68
,
61
are resiliently engaged with the engaging members
68
,
68
,
61
. The right-side first overhead cover
64
A is supported in the right-side first dummy cover
42
A by the resilient engagement permitting detachment or attachment.
The engaging member
61
is formed cylindrically. The engaging members
68
,
68
are formed in a cylindrical shape having an ellipse cross-sectional shape which extends upwardly and downwardly. The upper portion of the right-side first overhead cover
64
A is in a state where the engaging projection
67
is resiliently engaged with an engaging member
69
pressed to the right-side first dummy cover
42
A side. The engaging projections
66
,
66
can be easily resiliently engaged with the engaging members
68
,
68
. The right-side first overhead cover
64
A can be easily mounted on the right-side first dummy cover
42
A.
In
FIGS. 14
to
16
, the left-side first overhead cover
65
A is formed of synthetic resin so as to cover the left side of the first head cover
35
A from above and the sides and are mounted on the left-side first dummy cover
43
A so as to be detachable or attachable.
The left-side first overhead cover
65
A has the side view formed of a substantially T shape as in the right-side first overhead cover
64
A so as to cover the bolts
60
. . . for mounting the left-side first dummy cover
43
A on the first head cover
35
A and the notch
83
provided in the left-side first dummy cover
43
A to arrange the spark plug
52
when mounted to the left-side first dummy cover
43
A.
In the upper portion of the left-side first overhead cover
65
A, a pair of engaging projections
70
,
70
project to the left-side first dummy cover
43
A side. In the lower portion of the left-side first overhead cover
65
A in the middle position between the engaging projections
70
,
70
, an engaging projection
71
protrudes to the left-side first dummy cover
43
A side.
In the left-side first dummy cover
43
A, cylindrical engaging members
72
,
72
made of synthetic resin are provided corresponding to both the engaging projections
70
,
70
and a cylindrical engaging member
73
made of synthetic resin corresponds to the engaging projection
71
. The engaging projections
70
,
70
,
71
inserted into the engaging members
72
,
72
,
73
are resiliently engaged with the engaging members
72
,
72
,
73
. The left-side first overhead cover
65
A is supported in the left-side first dummy cover
43
A by the resilient engagement permitting detachment or attachment.
The engaging member
73
is formed cylindrically. The engaging members
72
,
72
are formed in a cylindrical shape having an ellipse cross-sectional shape which extends upwardly and downwardly. The upper portion of the left-side first overhead cover
65
A is in a state where the engaging projection
71
is resiliently engaged with the engaging member
73
pressed to the left-side first dummy cover
43
A side. The engaging projections
70
,
70
can be easily resiliently engaged with the engaging members
72
,
72
. The left-side first overhead cover
65
A can be easily mounted on the left-side first dummy cover
43
A.
Again in
FIGS. 2 and 3
, the right side of the second cylinder head
34
B of the second bank BB is covered by a right-side second dummy cover
42
B. The left side of the second cylinder head
34
B is covered by a left-side second dummy cover
43
B thereof. The dummy covers
42
B,
43
B are intended for enhancing the functional beauty of the engine E and are made of metal to eliminate heat and to enhance the functional beauty. An equal plurality of fins
44
B . . . ,
45
B . . . as dummy cooling fins are provided on the sides of the dummy covers
42
B,
43
B, respectively.
At least one spot (two spots in this embodiment) of the dummy covers
42
B,
43
B is fastened to the second head cover
35
B as part of the engine main unit
32
as in the dummy covers
42
A,
43
A of the first bank BA. The lower portions of the dummy covers
42
B,
43
B are fittedly supported in the upper portion of the second cylinder
33
B, as in the dummy covers
42
A,
43
A of the first bank BA. The right-side and left-side second dummy covers
42
B,
43
B are provided with the notches for arranging the spark plugs mounted on the second cylinder head
34
B, as in the right-side and left-side first dummy covers
42
A,
43
A.
At least part of the second head cover
35
B coupled to the second cylinder head
34
B is covered by a right-side second overhead cover
64
B and a left-side second overhead cover
65
B.
The right-side second overhead cover
64
B is formed of synthetic resin so as to cover the right side of the second head cover
35
B from above and the sides and is mounted on the right-side second dummy cover
42
B so as to be detachable or attachable, as in the right-side first overhead cover
64
A on the first bank BA side. The left-side second overhead cover
65
B is formed of synthetic resin so as to cover the left side of the second head cover
35
B from above and the sides and is mounted on the left-side second dummy cover
43
B so as to be detachable or attachable, as in a left-side second overhead cover
64
B on the first bank BA side.
The right-side and left-side second overhead covers
64
B,
65
B have the side view formed in a substantially T shape so as to cover the fastening portion of the right-side and left-side second dummy covers
42
B,
43
B to the second head cover
35
B. The right-side and left-side second overhead covers
64
B,
65
B cover the notches of the right-side and left-side second dummy covers
42
B,
43
B.
To reduce the nip angle of the first and second banks BA, BB, in a plane orthogonal to the axis of the crankshaft
30
, a cross point CP of the cylinder axes CA, CB of both the banks BA, BB is arranged in a position offset, for example, forward from the axis of the crankshaft
30
. In the plane, a length LA
1
between a deck surface
75
A of the first cylinder head
34
A of the first bank BA and the cross point CP and a length LB
1
between a deck surface
75
B of the second cylinder head
34
B of the second bank BB and the cross point CP are different from each other so that LA
1
<LB
1
.
The lengths LA
1
and LB
1
are different so that a difference in height between both the banks BA, BB is significant visually. A feeling of unbalance may be produced, resulting in a deterioration of the functional beauty of the engine E.
The total numbers of a plurality of the fins
40
A . . . ,
44
A . . . ,
45
A . . . ,
40
B . . . ,
44
B . . . ,
45
B . . . provided in the sides of the cylinders
33
A,
33
B of the first and second banks BA, BB and the sides of the dummy covers
42
A,
43
A;
42
B,
43
B for covering the head covers
34
A,
34
B coupled to the cylinders
33
A,
33
B from both the right and left sides and aligned in the direction along the cylinder axes CA, CB of both the banks BA, BB are set to be equal in the first and second banks BA, BB. A center line mutual distance dA of the fins
40
A . . . ,
44
A . . . ,
45
A . . . on the first bank BA side and a center line mutual distance dB of the fins
40
B . . . ,
44
B . . . ,
45
B . . . on the second bank BB side are set to be almost equal, as shown in FIG.
17
.
The lengths LA
2
, LB
2
between the center lines of the fins
40
A,
40
B closest to the crankshaft
30
of the fins
40
A . . . ,
44
A . . . ,
45
A . . . ,
40
B . . . ,
44
B . . . ,
45
B . . . and the cross point CP in the plane orthogonal to the axis of the crankshaft
30
are set to be almost equal in the first and second banks BA, BB.
In the side view in the direction along the axis of the crankshaft
30
, the contour shapes of the first and second cylinders
33
A,
33
B including the fins
40
A
40
B . . . and the dummy covers
42
A,
43
A;
42
B,
43
B including the fins
44
A,
45
A;
44
B,
45
B are formed almost symmetrically with respect to a plane including a bisector
76
between both the banks BA, BB passing through the cross point CP in the plane orthogonal to the axis of the crankshaft
30
.
A length LA
3
between cross points at which the right-side and left-side first overhead covers
64
A,
65
A cross the cylinder axis CA of the first cylinder
33
A in a plane orthogonal to the axis of the crankshaft
30
and the cross point CP at which the cylinder axes CA, CB cross each other in the plane and a length LB
3
between a cross point at which the right-side and left-side second overhead covers
64
B,
65
B cross the cylinder axis CB of the second cylinder
33
B in a plane orthogonal to the axis of the crankshaft
30
and the cross point CP at which the cylinder axes CA, CB cross each other in the plane are set to be almost equal.
The front portion of the fist cylinder head
34
A of the first bank BA is connected to the upstream end of an exhaust pipe
77
A extended rearwardly on the right side of the body frame
21
. The rear portion of the second cylinder head
34
B of the second bank BB is connected to the upstream end of an exhaust pipe
77
B formed to be bent on the right side of the body frame
21
. Exhaust mufflers
78
A,
78
B arranged on the right side of the rear wheel WR are connected to the downstream ends of the exhaust pipes
77
A,
77
B. High tension cords
79
,
80
. . . continuous to the pair of spark plugs
51
,
52
. . . mounted on each of the cylinder heads
34
A,
34
B of both the banks BA, BB are drawn upwardly from between the right-side and left-side first overhead covers
64
A,
65
A and the right-side and left-side second overhead covers
64
B,
65
B.
The operation of this embodiment will be described. In the sides of the cylinders
33
A,
33
B of the first and second banks BA, BB and the sides of the dummy covers
42
A,
43
A;
42
B,
43
B for covering the head covers
34
A,
34
B from both the right and left sides, the plurality of fins
40
A . . . ,
44
A . . . ,
45
A . . . ;
40
B . . . ,
44
B . . . ,
45
B . . . aligned in the direction along the cylinder axes CA, CB of the first and second cylinders
33
A,
33
B are provided so that the total numbers of the fins
40
A . . . ,
44
A . . . ,
45
A . . . ;
40
B . . . ,
44
B . . . ,
45
B . . . and the center line mutual distances dA and dB of the fins
40
A . . . ,
44
A . . . ,
45
A . . . ;
40
B . . . ,
44
B . . . ,
45
B . . . are almost equal in the first and second banks BA, BB. The lengths LA
2
, LB
2
between the center lines of the fins
40
A,
40
B closest to the crankshaft
30
of the fins
40
A . . . ,
44
A . . . ,
45
A . . . ;
40
B . . . ,
44
B . . . ,
45
B . . . and the cross point CP in the plane orthogonal to the axis of the crankshaft
30
are set to be almost equal in the first and second banks BA, BB.
The fins
40
A . . . ,
44
A . . . ,
45
A . . . ;
40
B . . . ,
44
B . . . ,
45
B . . . for enhancing the appearance have a function to decide the appearance shape of both the banks BA, BB. In the above-described construction, the fins
40
A . . . ,
44
A . . . ,
45
A . . . ;
40
B . . . ,
44
B . . . ,
45
B . . . in both the banks BA, BB are arranged corresponding to almost the same position along the cylinder axes CA, CB of the banks BA, BB. A visual impression so that the heights of both the banks BA, BB are not different can be obtained. The functional beauty of the V-type engine E can be enhanced and the marketability of the engine E can be improved.
In the side view in the direction along the axis of the crankshaft
30
, the contour shapes of the first and second cylinders
33
A,
33
B including the fins
40
A . . . ,
40
B . . . and the dummy covers
42
A,
43
A;
42
B,
43
B including the fins
44
A,
45
A;
44
B,
45
B are formed almost symmetrically with respect to a plane including the bisector
76
between both the banks BA, BB passing through the cross point CP of the cylinder axes CA, CB of both the banks BA, BB. The contours of the first and second banks BA, BB are shaped almost symmetrically. The functional beauty of the V-type engine E can be enhanced and the marketability can be improved.
The lengths LA
3
, LB
3
between cross points at which the right-side and left-side first overhead covers
64
A,
65
A and the right-side and left-side second overhead covers
64
B,
65
B for covering at least part of the first and second head covers
35
A,
35
B or the right and left sides of the first and second head covers
35
A,
35
B in this embodiment from above and the sides cross the cylinder axes CA, CB of the first and second cylinders
33
A,
33
B in a plane orthogonal to the axis of the crankshaft
30
and the cross point CP at which both the cylinder axes CA, CB cross each other in the plane are set to be almost equal in both the banks BA, BB. The height difference and the appearance shape difference of both the banks BA, BB appear to be small. The functional beauty of the V-type engine E can be enhanced and the marketability can be improved.
In the banks BA, BB, to the head covers
35
A,
35
B as part of the engine main unit
32
, the right-side and left-side first dummy covers
42
A,
43
A and the right-side and left-side second dummy covers
42
B,
43
B for covering the cylinder heads
34
A,
34
B from the right and left sides are fastened in at least one spot thereof or two spots thereof in this embodiment.
The dummy covers
42
A,
43
A;
42
B,
43
B are provided with the fins
44
A,
45
A;
44
B,
45
B are formed of metal to eliminate heat and to enhance the functional beauty. Strong support is thus required. As described above, at least one spot of the dummy covers
42
A,
43
A;
42
B,
43
B is fastened to the engine main unit
32
. The dummy covers
42
A,
43
A;
42
B,
43
B can be supported strongly in the engine main unit
32
.
In many cases, the overhead covers
64
A,
65
A;
64
B,
65
B require no fins and are formed of synthetic resin as lightweight material since requirements to eliminate heat and to enhance the functional beauty are relatively low. The overhead covers
64
A,
65
A;
64
B,
65
B need not be supported very strongly.
The plurality of engaging projections
66
. . . ,
67
;
70
. . . ,
71
provided in the overhead covers
64
A,
65
A;
64
B,
65
B are resiliently engaged with the dummy covers
42
A,
43
A;
42
B,
43
B so as to be detachable or attachable. The dummy covers
42
A,
43
A;
42
B,
43
B and the overhead covers
64
A,
65
A;
64
B,
65
B can be supported in the engine main unit
32
in a construction suitable thereto.
The bolts
49
,
60
. . . for fastening at least one spot of the dummy covers
42
A,
43
A;
42
B,
43
B to the engine main unit
32
are covered by the overhead covers
64
A,
65
A;
64
B,
65
B constructing the parts of a special shape with a surface treatment which has been required since the bolts
49
,
60
. . . are exposed to outside is unnecessary. The cost can be reduced and the functional beauty of the engine E can be enhanced.
The right-side first and second dummy covers
42
A,
42
B and the left-side first and second dummy covers
43
A,
43
B are provided with the notches
53
. . . ,
83
. . . for arranging the spark plugs
51
. . . ,
52
. . . mounted on the cylinder heads
34
A,
34
B. The right-side first and second overhead covers
64
A,
65
A and the left-side first and second overhead covers
64
B,
65
B are formed in a shape to cover the notches
53
. . . ,
83
. . . from above. The notches
53
. . . ,
83
. . . for arranging the spark plugs
51
. . . ,
52
. . . are covered by the overhead covers
64
A,
65
A,
64
B,
65
B from above. The functional beauty can be enhanced.
The plurality of engaging projections
66
,
66
,
67
. . . ,
70
,
70
,
71
. . . provided in the overhead covers
64
A,
64
B,
65
A,
65
B are resiliently engaged with the dummy covers
42
A,
42
B,
43
A,
43
B so as to be detachable or attachable. The overhead covers
64
A,
65
B,
65
A,
65
B can be easily detached or attached. The maintenance operability of the spark plugs
51
. . . ,
52
. . . can be improved.
In portions corresponding to the fins
40
A,
40
B closest to the cylinder heads
34
A,
34
B of the plurality of fins
40
A . . . ,
40
B . . . , provided in the sides of the cylinders
33
A,
33
B aligned in the direction along the cylinder axes CA, CB, at least one (two in this embodiment) of the recesses
55
. . . ,
62
. . . is provided in the cylinders
33
A,
33
B. The projections
54
. . . ,
61
. . . provided in the dummy covers
42
A,
43
A;
42
B,
43
B are fitted in the recesses
55
. . . ,
62
. . . .
The dummy covers
42
A,
43
A;
42
B,
43
B are supported by the cylinders
33
A,
33
B of the engine main unit
32
together with a fastening of at least one spot thereof to the engine main unit
32
with the bolts
49
,
60
. The dummy covers
42
A,
43
A;
42
B,
43
B which become relatively very heavy can be fixed reliably to the engine main unit
32
. The mutual fitting portions of the dummy covers
42
A,
43
A;
42
B,
43
B and the cylinders
33
A,
33
B can be hidden by the fins
40
A,
40
B provided in the cylinders
33
A,
33
B. The mutual fitting of the dummy covers
42
A,
43
A;
42
B,
43
B and the cylinders
33
A,
33
B will not deteriorate the functional beauty of the engine E.
The embodiment of the present invention are described above. The present invention is not limited to the embodiment and can make various design modifications without deviating from the present invention described in claims.
The present invention can be applied to a V-type engine for a motorcycle in which at least part of the first and second cylinders
33
A,
33
B is covered from the sides by the dummy covers having a plurality of fins projecting from sides thereof, a V-type engine for a motorcycle in which a plurality of fins are provided projecting from the sides of the first and second cylinder heads
34
A,
34
B, and a V-type engine for a motorcycle wherein the overhead covers for covering at least part of the head covers from above and the sides are not mounted.
As described above, in the present invention the heights of a pair of banks are visually recognized to be almost equal. The functional beauty of the engine can be enhanced and the marketability can be improved.
In the present invention, the first and second cylinders are shaped almost symmetrically. The functional beauty of the V-type engine can be enhanced and the marketability can be improved.
In the present invention, the height difference and the appearance shape difference between both the banks appear to be smaller. The functional beauty of the V-type engine can be enhanced and the marketability can be improved.
The invention being thus described, it will be obvious that the same may be varied in many ways. Such variations are not to be regarded as a departure from the spirit and scope of the invention, and all such modifications as would be obvious to one skilled in the art are intended to be included within the scope of the following claims.
Claims
- 1. A V-type engine for a motorcycle having a first bank with a first cylinder coupled to a first cylinder head and a second bank having a second cylinder coupled to a second cylinder head being arranged in a V-shape in a plane orthogonal to the axis of a crankshaft with a length between a cross point at which cylinder axes of the first and second cylinders cross each other in said plane and a deck surface of the first cylinder head and a length between said cross point and a deck surface of the second cylinder head being set to be different relative to each other comprising:a plurality of fins aligned in the direction along the cylinder axes of the first and second cylinders are provided on sides of the first and second cylinders or sides of dummy covers for covering at least part of the first and second cylinders from the sides and sides of the first and second cylinder heads or sides of the dummy covers for covering at least part of the first and second cylinder heads from the sides; wherein the total numbers of the fins and center line mutual distances of the fins are almost equal in the first and second banks, and lengths in said plane between the center lines of the fins closest to the crankshaft of said fins and said cross point are set to be almost equal in the first and second banks.
- 2. The V-type engine for a motorcycle according to claim 1, wherein contour shapes including said fins of the first and second cylinders or the dummy covers for covering at least part of the first and second cylinders from the sides and the first and second cylinder heads or the dummy covers for covering at least part of the first and second cylinder heads from the sides are formed almost symmetrically with respect to a plane including a bisector between both the banks passing though said cross point in the side view in the direction along the axis of said crankshaft.
- 3. The V-type engine for a motorcycle according to claim 2, wherein lengths between cross points at which first and second head covers coupled to the first and second cylinder heads or first and second overhead covers for covering at least part of the first and second head covers from above and the sides cross the cylinder axes of the first and second cylinders in said plane and the cross point at which the cylinder axes of the first and second cylinders cross each other in said plane are set to be almost equal in the first and second banks.
- 4. The V-type engine for a motorcycle according to claim 1, wherein lengths between cross points at which first and second head covers coupled to the first and second cylinder heads or first and second overhead covers for covering at least part of the first and second head covers from above and the sides cross the cylinder axes of the first and second cylinders in said plane and the cross point at which the cylinder axes of the first and second cylinders cross each other in said plane are set to be almost equal in the first and second banks.
- 5. The V-type engine for a motorcycle according to claim 1, wherein the dummy cover for covering the first and second cylinders includes a resilient member for mating with bosses formed in the first and second cylinders for securing the dummy cover relative thereto.
- 6. The V-type engine for a motorcycle according to claim 5, and further including projections formed on said dummy cover for engaging with recesses formed in said first and second cylinders for mounting the dummy cover relative thereto.
- 7. The V-type engine for a motorcycle according to claim 5, wherein said dummy covers for covering at least part of the first and second cylinder heads include projections for mounting relative to said dummy cover for covering the first and second cylinders.
- 8. The V-type engine for a motorcycle according to claim 7, and further including engaging members formed in dummy cover for covering the first and second cylinders for engaging with the projections formed on said dummy covers for covering at least part of the first and second cylinder heads.
- 9. The V-type engine for a motorcycle according to claim 8, wherein said engaging members formed in dummy cover for covering the first and second cylinders for engaging with the projections formed on said dummy covers for covering at least part of the first and second cylinder heads include a resilient surface for engaging and securely mounting the projections formed on said dummy covers for covering at least part of the first and second cylinder heads.
- 10. The V-type engine for a motorcycle according to claim 1, wherein said dummy covers for covering at least part of the first and second cylinder heads are formed in the shape of a T.
- 11. A V-type engine for a motorcycle having a first bank with a first cylinder coupled to a first cylinder head and a second bank having a second cylinder coupled to a second cylinder head being arranged in a V-shape in a plane orthogonal to the axis of a crankshaft wherein a head surface of said first and second cylinders is not on the same plane relative to each other comprising:at least one dummy cover for covering at least part of the first or second cylinders from the side for enabling an alignment of said the head surface of said first and second cylinders to be on substantially the same horizontal plane relative to each other by covering and extending at least part of the first or second cylinder heads from the sides.
- 12. The V-type engine for a motorcycle according to claim 11, wherein a contour shape of said dummy cover includes fins for corresponding to fins of the first and second cylinders.
- 13. The V-type engine for a motorcycle according to claim 12, and further including at least one head cover for covering at least part of the head surface of said first or second cylinders, wherein a length between cross points at which said at least one head cover coupled to the first or second cylinder heads and a cylinder head of said second or first cylinder is set to be almost equal in the first and second banks.
- 14. The V-type engine for a motorcycle according to claim 11, and further including at least one head cover for covering at least part of the head surface of said first or second cylinders, wherein a length between cross points at which said at least one head cover coupled to the first or second cylinder heads and a cylinder head of said second or first cylinder is set to be almost equal in the first and second banks.
- 15. The V-type engine for a motorcycle according to claim 11, wherein the at least one dummy cover for covering the first or second cylinders includes a resilient member for mating with bosses formed in the first and second cylinders for securing the at least one dummy cover relative thereto.
- 16. The V-type engine for a motorcycle according to claim 15, and further including projections formed on said at least one dummy cover for engaging with recesses formed in said first or second cylinders for mounting the at least one dummy cover relative thereto.
- 17. The V-type engine for a motorcycle according to claim 15, wherein said at least one dummy covers for covering at least part of the first or second cylinder heads include projections for mounting relative to said at least one dummy cover for covering the first and second cylinders.
- 18. The V-type engine for a motorcycle according to claim 17, and further including engaging members formed in the at least one dummy cover for covering the first and second cylinders for engaging with projections formed on a dummy cover for covering at least part of the head surface of said first or second cylinders.
- 19. The V-type engine for a motorcycle according to claim 18, wherein said at least one dummy cover for covering at least part of the head surface of said first or second cylinders is formed in the shape of a T.
- 20. The V-type engine for a motorcycle according to claim 18, wherein said engaging members formed in at least one dummy cover for covering the first or second cylinders for engaging with the projections formed on said at least one dummy cover for covering at least part of the head surface of said first or second cylinders include a resilient surface for engaging and securely mounting the projections formed on said at least one dummy cover for covering at least part of the head surface of said first or second cylinders.
Priority Claims (1)
Number |
Date |
Country |
Kind |
2001-273597 |
Sep 2001 |
JP |
|
Foreign Referenced Citations (1)
Number |
Date |
Country |
60-53625 |
Mar 1985 |
JP |