Information
-
Patent Grant
-
6799548
-
Patent Number
6,799,548
-
Date Filed
Tuesday, May 22, 200123 years ago
-
Date Issued
Tuesday, October 5, 200419 years ago
-
Inventors
-
Original Assignees
-
Examiners
- Yuen; Hanry C.
- Benton; Jason
Agents
-
CPC
-
US Classifications
Field of Search
-
International Classifications
-
Abstract
A main bearing case has a bearing holder for holding a bearing for supporting a crankshaft, and a crankcase mounting section at which it is joined to a crankcase. Spherical rib walls are formed on one face of the main bearing case opposite to the crankcase for connecting the bearing holder and the crankcase mounting section, on the upper side with respect to the axis of the crankshaft. Force radially exerted to the crankshaft is received by these rib walls, increasing the rigidity of the main bearing case, whereby deformation and play thereof are prevented.
Description
BACKGROUND OF THE INVENTION
The present invention relates to a bearing case for supporting a bearing of a crankshaft in an engine.
General-purpose engines of an overhead valve (OHV) type or an overhead camshaft (OHC) type are widely used as power sources for lawn mowers, power-driven sprayers, generators, and others. The crankshaft of such engines is generally supported by ball bearings (hereinafter referred to simply as “bearing”). In most cases, the crankshaft is supported at both ends thereof by the bearings.
The bearings are held in a crankcase and/or a main bearing case (hereinafter referred to simply as “bearing case”) mounted thereto. Generally, the bearing on one side is accommodated in and held by a bearing holder provided in a wall of the crankcase, while the other bearing is accommodated in and held by the bearing case.
FIG. 7
is a cross-sectional view showing a structure of a conventional bearing case. The conventional bearing case
100
includes a bearing holder
102
protruded at the center of a side wall
101
as shown in FIG.
7
. Along an outer periphery of the bearing case
100
is formed a crankcase mounting section
103
(hereinafter referred to simply as “mounting section”) which is to be joined to a cover mounting surface of the crankcase through a gasket. A hollow
104
is formed between the mounting section
103
and the bearing holder
102
. The bearing holder
102
accommodates a ball bearing (not shown) therein and thereby supports one end of the crankshaft.
Apart from a force in an axial direction, the crankshaft is subjected to a force exerted orthogonally thereto in an explosion stroke. The bearing accordingly receives the force exerted thereto in a radial direction orthogonal to the crankshaft in addition to the force in the rotational direction. The bearing case
100
shown in
FIG. 7
receives such force in the bearing holder
102
.
The bearing case
100
, however, has a mounting section
103
overhung from the bearing holder
102
, and therefore when subjected to a radially acting force, the bearing holder
102
warps from its base end, resulting in deformation in the side wall
101
. The radially exerted force also acts on the mounting section
103
as moment, whereupon a compressive force and a shearing force act between the mounting section
103
and the crankcase. The gasket interposed therebetween is subjected to such forces repeatedly and is accordingly deformed over and over again. Thus deterioration of the gasket proceeds quickly, leading to the risk of oil leakage.
In the high-performance engines with higher speed for higher output in recent years, the bearing holder
102
is subjected to ever increasing load. The bearing case shown in
FIG. 7
is hardly capable of withstanding such load, and therefore an improvement in the structure of bearing case has been desired.
SUMMARY OF THE INVENTION
An object of the present invention is to provide a rigid and light bearing case.
In order to achieve the object, there is provided a bearing case for an engine according to the present invention, which is attached to a crankcase of the engine for supporting the bearing of a crankshaft in the engine, and includes a bearing holder for holding the bearing, a crankcase mounting section formed on an outer peripheral surface of the bearing case to be joined to the crankcase, and a rib wall formed in the bearing case on a side of the crankcase and extending between the bearing holder and the crankcase mounting section.
According to the present invention, a force acting on the bearing holder in a radial direction through the crankshaft is received by the rib wall, so that the bearing holder can be prevented from warping at its base end as the conventional bearing case. Also, the crankcase mounting section receives less moment, whereby its movement is restricted. As a result, damage to the gasket caused by deformation or play of the bearing case is prevented, whereby the lifetime and reliability of the product are improved.
The rib wall may be formed in a spherical shape so as to better support the bearing holder by arched wall surface, thereby enhancing the rigidity of the bearing case. The thickness of the rib wall can be reduced accordingly so as to make the bearing case more lightweight. Vibration and operation noise can also be absorbed and restricted more efficiently by the spherical wall, resulting in overall enhancement of the product performance.
The rib wall is preferably formed on an upper side of the bearing case with respect to the axis of the crankshaft. The lower side of the bearing case is less affected by the radially acting force, and so the rib wall therefor is omitted, thereby increasing a degree of freedom of design with respect to the lower side, from the axis of the crankshaft, of the bearing case.
Additionally, a cavity may be formed on the lower side of the bearing case with respect to the axis of the crankshaft, so as to open toward the side of the crankcase and to form part of an oil pan for the engine. Thereby, the rigidity of the bearing case is improved while the oil reservoir capacity is secured.
The bearing case may further include a reinforcing rib formed along the outer periphery thereof on one surface of the crankcase mounting section on the opposite side from the crankcase, for securing rigidity of the bearing case in its surface direction.
Preferably, the crankcase mounting section includes a plurality of bolt holes for passing a plurality of bolts therethrough so as to fixedly couple the bearing case to the crankcase, the reinforcing rib being formed so as to connect these bolt holes. The reinforcing rib is preferably formed to part of the bearing case where the above-mentioned rib wall exists.
BRIEF DESCRIPTION OF THE DRAWINGS
These and other objects and advantages of the present invention will become clearly understood from the following description with reference to the accompanying drawings, wherein:
FIG. 1
is a diagram given in explanation of the structure of an OHC engine in which a bearing case according to one embodiment of the present invention is applied;
FIG. 2
is an explanatory cross-sectional view along a direction of axis of the cylinder in the engine of
FIG. 1
;
FIG. 3
is a cross-sectional view showing the structure of the bearing case according to the present invention;
FIG. 4
is a left side view of the bearing case of
FIG. 3
;
FIG. 5
is a right side view of the bearing case of
FIG. 3
;
FIG. 6
is a cross-sectional view taken along the line A—A in
FIG. 5
; and
FIG. 7
is a cross-sectional view showing the structure of a conventional bearing case.
DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS
Preferred embodiments of the present invention will be hereinafter described in detail with reference to the accompanying drawings.
FIG. 1
is a diagram given in explanation of the structure of an OHC engine in which a bearing case according to one embodiment of the invention is applied.
FIG. 2
is an explanatory cross-sectional view taken along a direction of the cylinder axis of the engine of FIG.
1
. The engine of
FIG. 1
is a single-cylinder 4-cycle gasoline engine, and is a so-called “inclined OHC engine” in which a cylinder axis CL is inclined by an angle θ with respect to the gravitational direction (see FIG.
2
). In the engine, an engine body
1
includes a cylinder block
2
and a crank case
3
which are integrally formed with each other. The engine body
1
is made of iron or a light metal alloy such as an aluminum alloy. A cylinder head
4
made of the aluminum alloy is attached to an upper portion of the cylinder block
2
. A rocker cover
5
made of a sheet metal or a synthetic resin is mounted on top of the cylinder head
4
.
The crank case
3
has a large opening on the right side thereof in
FIG. 1
, thereby providing a main bearing case attachment surface
6
. A main bearing case
7
(hereinafter referred to simply as “bearing case”) made of the aluminum alloy is attached to the main bearing case attachment surface
6
. Thus, a crank chamber
8
is provided in the crank case
3
, and an oil pan
10
is provided under the crank chamber
8
for storing a lubricating oil (hereinafter referred to simply as “oil”)
9
.
A main bearing
11
a
is press-fitted into the main bearing case
7
, and one end of a crankshaft
12
is supported by the main bearing
11
a
. An oil seal
13
a
is press-fitted on the outer side of the main bearing
11
a.
FIG. 3
is a cross-sectional view of the bearing case
7
,
FIG. 4
being a left side view and
FIG. 5
being a right side view of same.
FIG. 6
is a cross-sectional view taken along the line A—A in FIG.
5
. The bearing case
7
has a bearing holder
61
substantially at its center for holding and accommodating the main bearing
11
a
, as shown in
FIGS. 3 through 6
. The bearing case
7
also includes a crankcase mounting section
62
(hereinafter referred to simply as “mounting section”) formed along its outer periphery, which is to be joined to the main bearing case mounting face
6
of the crankcase
3
. The bearing case
7
is coupled to the crankcase
3
by bolts, and therefore the mounting section
62
includes a plurality of bolt holes
67
for passing the bolts therethrough. Although not shown, a gasket is interposed between the main bearing case mounting face
6
and the mounting section
62
.
The crankshaft
12
receives an cyclic force at an expansion stroke of a combustion as mentioned above which is exerted in a radial direction. Accordingly, the bearing holder
61
is subjected to such a force through the main bearing
11
a
. The force acts on the upper side of the bearing holder
61
from the center of the crankshaft towards the cylinder, and therefore the upper side of the bearing holder
61
is particularly affected. In view of the above, the bearing case
7
according to the present invention has a spherical wall for connecting the inner side end of the bearing holder
61
and that of the mounting section
62
to receive the load exerted on the upper, inner side of the bearing holder
61
.
More specifically, as shown in
FIG. 3
, the bearing case
7
includes a plurality of rib walls
63
on the upper side with respect to the axis of the crankshaft
12
, on the face to which the crankcase
3
is connected. The rib walls
63
extend from the vicinity of the inner side end
61
a
of the bearing holder
61
towards the vicinity of the inner side end
62
a
of the mounting section
62
, thereby directly connecting the bearing holder
61
and the mounting section
62
. Referring now to
FIG. 4
, the three faces X, Y, Z defined on the upper side of two radially extending ribs
64
a
,
64
b
construct the rib walls
63
.
The rib walls
63
are formed as part of a spherical surface of a large radius having a center concentric with the axis of the crankshaft. In other words, the rib walls
63
are curved, one side face thereof bulging upward from the plane of
FIG. 4
, respectively.
Therefore, the force which is applied in a radial direction thereof to the bearing holder
61
via the crankshaft
12
as mentioned above is transmitted to the rib walls
63
, so that the bearing holder
61
is supported by the rib walls
63
. Thus, the bearing holder
61
does not warp or distort at its base end as in the prior art, and the bearing case
7
is accordingly prevented from being deformed. Also, the mounting section
62
receives less moment, resulting in less play thereof. In other words, the overall rigidity of the bearing case
7
is improved, whereby damage to the gasket is prevented, leading to improved lifetime and reliability of the product.
Moreover, the bearing holder
61
of the bearing case
7
is supported on the arched wall surface because of the spherical structure of the rib walls
63
, securing high rigidity. In view of this, the rib walls
63
can be made thinner than other portion accordingly, whereby the weight of the bearing case
7
can be reduced. The spherical wall surfaces also absorb and restrict vibration and operating noise efficiently, whereby the overall performance of the product is enhanced.
The other three faces P, Q, and R on the lower side of the ribs
64
a
,
64
b
form cavities
65
, respectively, as shown in
FIGS. 3 and 4
. These cavities
65
open toward the side of the crankcase
3
of the engine, forming a part of the oil pan
10
. Since the lower side of the bearing holder
61
is subjected to less load as described above, rib walls
63
should not necessarily be provided also to the lower side of the bearing case
7
. In view of this, the lower side of the bearing holder
61
is formed with cavities
65
and not with the rib walls
63
in this preferred embodiment, so as to secure a certain capacity for containing oil
9
and to achieve a reduction in weight of the bearing case
7
. Of course, the lower side faces P, Q, and R may also be formed as the rib walls
63
if an enough amount of oil can be held without such cavities
65
.
The bearing case
7
of the invention further has a reinforcing rib
66
provided on the upper side of the outer side face
62
b
of the mounting section
62
, as shown in
FIGS. 3 and 5
. The reinforcing rib
66
extends along the periphery of the mounting section
62
so as to connect the four bolt holes
67
a
,
67
b
,
67
c
, and
67
d
provided on the side where the rib walls
63
are formed. Such reinforcing rib
66
may be formed around the entire periphery of the bearing case
7
.
In the prior art shown in
FIG. 7
, the rigidity in the surface direction of the bearing case
100
(hereinafter referred to simply as “surface rigidity”) was secured by the outer peripheral wall
105
extending along the mounting section
103
. In the bearing case
7
of the invention, while the lower part thereof has required surface rigidity secured by the outer peripheral wall
68
forming the cavities
65
, the surface rigidity of the upper part of the bearing case is dependent on the thickness of the rib walls
63
. Thus the upper part may have a relatively low surface rigidity compared to that of the lower part. Accordingly, the bearing case
7
of the present invention is provided with the reinforcing rib
66
on the outer side face
62
b
of the mounting section
62
so as to secure the surface rigidity in part where the rib walls
63
are formed. In this way, the bearing case
7
of the invention has sufficient rigidity of the case itself, because of withstanding the force exerted orthogonally to the crankshaft
12
. A main bearing
11
b
is press-fitted into a wall surface
14
of the crank case
3
opposite to the main bearing case attachment surface
6
. The other end side of the crankshaft
12
is supported by the main bearing
11
b
. Similarly, an oil seal
13
b
is provided on the outer side of the main bearing
11
b
. The oil seals
13
a
and
13
b
prevent the oil
9
stored in the oil pan
10
from leaking out of the crank case
3
along the crankshaft
12
.
A flywheel
15
and a cooling fan
16
are attached to the other end portion of the crankshaft
12
that extends out of the crank case
3
through the wall surface
14
. The cooling fan
16
is provided outside the crank case
3
and within a casing
57
, and rotates together with the crankshaft
12
so as to introduce a cooling air from an outside of the casing
57
. The engine body
1
and the cylinder head
4
are cooled by the introduced cooling air. Moreover, a recoil device
17
is provided on the outer side of the casing
57
. By pulling a recoil lever
17
a
by hand, the crankshaft
12
is rotated to start the engine.
A cylinder bore
18
is provided in the cylinder block
2
. A piston
19
is fitted within the cylinder bore
18
so as to be slidable therein. An upper end of the cylinder bore
18
is closed by the cylinder head
4
, and an upper surface of the piston
19
and a bottom wall surface
20
of the cylinder head
4
together form a combustion chamber
21
. An intake valve
22
, an exhaust valve (not shown), an ignition plug (not shown) are provided facing the upper portion of the combustion chamber
21
.
A small end portion
25
of a connecting rod
24
is rotatably connected to the piston
19
via a piston pin
23
.
A crank pin
27
of the crankshaft
12
is rotatably connected to a large end portion
26
of the connecting rod
24
. Thus, the crankshaft
12
is rotated along with the vertical reciprocation of the piston
19
.
A camshaft
28
is provided in the cylinder head
4
in parallel with the crankshaft
12
on the cylinder axis CL. The camshaft
28
includes a valve-operating cam
29
and a sprocket
31
, which are integrally formed with each other. The valve-operating cam
29
is driven in synchronization with the crankshaft
12
by a timing system
30
.
A sprocket
32
is secured on the crankshaft
12
. Chain chambers
50
and
51
are provided in the cylinder block
2
and the cylinder head
4
, respectively, and the sprocket
31
and the sprocket
32
are connected to each other via a chain
33
provided in the chain chambers
50
and
51
. The sprockets
31
,
32
and the chain
33
form the timing system
30
. The number of teeth of the sprocket
31
is twice as large as the number of teeth of the sprocket
32
, so that the valve-operating cam
29
undergoes one revolution per two revolutions of the crankshaft
12
. The chain
33
is provided with an appropriate tension by a chain tensioner
55
.
The valve-operating cam
29
is provided with a cam surface
29
a
, and a slipper
35
formed at one end of a rocker arm
34
slidably contacts with the cam surface
29
a
. Two rocking type rocker arms
34
are provided respectively for intaking and exhausting air. Each of the rocker arms
34
is provided to rock around a rocker shaft
36
which is supported by a rocker support
59
. The other end of each rocker arm
34
is connected to a top end portion of the intake valve
22
or an exhaust valve (not shown) via an adjust screw
56
. The intake valve
22
and the exhaust valve are each driven as the rocker arm
34
is rocked by the valve-operating cam
29
. The intake valve
22
and the exhaust valve are each biased by a valve spring
37
toward the closed position. Thus, the intake valve
22
is opened/closed along with the rotation of the valve-operating cam
29
.
The timing system
30
is lubricated by a scraper
38
provided on a large end portion
26
of the connecting rod
24
. As illustrated in
FIG. 2
, the scraper
38
extends downward from a lower member
39
of the large end portion
26
, i.e., in a radial direction of the crankshaft
12
. The scraper
38
rocks along with the rotation of the crankshaft
12
through a path as indicated by a one-dotted-chain line in FIG.
2
. Thus, the oil
9
stored in the oil pan
10
is scraped up by the scraper
38
, and the oil
9
is splashed onto the chain
33
when the scraper
38
comes out of an oil surface
40
, thereby lubricating the timing system
30
.
The scraper
38
, having a generally L-shaped cross section, includes a bottom wall
41
and a side wall
42
extending integrally with the bottom wall
41
along one side of the bottom wall
41
. In the present embodiment, the angle between the bottom wall
41
and the side wall
42
is set to be 90°. However, the angle therebetween is not limited to the right angle, but may be appropriately selected in the range of about 60° to about 90°.
Along with the rocking of the scraper
38
, the oil
9
is scraped up by the bottom wall
41
, and the oil
9
scraped up by the bottom wall
41
is guided to the side wall
42
and splashed away from the side wall
42
. Thus, the droplets of the oil
9
are splashed also in three-dimensionally inclined directions, i.e., in the lateral direction from the scraper
38
, thereby throwing a little amount of droplets of the oil
9
toward the root end portion of the chain tensioner
55
. A little amount of the droplets hit the inner wall of the crank case
3
and are bounced back toward the chain
33
. In this way, droplets of the oil
9
can be supplied to the chain
33
, which is offset toward the main bearing case
7
with respect to the scraper
38
, thereby ensuring the supply of the oil
9
to the chain
33
.
The oil
9
thus splashed onto the chain
33
is transferred toward the cylinder head
4
along with the movement of the chain
33
, thereby lubricating the sprocket
31
also. Moreover, the sprocket
32
is also lubricated by the oil
9
attached on the chain
33
.
On the side of the cylinder head
4
, a little amount of the oil
9
attached on the chain
33
is shaken off by a centrifugal force. Specifically, as a portion of the chain
33
travels around the sprocket
31
, a little amount of the oil
9
on that portion of the chain
33
is thrown off the chain
33
in the circumferential direction of the sprocket
31
. In the illustrated engine, the rocker cover
5
is provided above the sprocket
31
, and those droplets of the oil
9
hit the ceiling surface
53
of the rocker cover
5
. The oil
9
attached onto the ceiling surface
53
runs down along the ceiling surface
53
back into the oil pan
10
via the chain chambers
51
and
50
.
The ceiling
53
of the rocker cover
5
includes a protrusion
54
as shown in
FIG. 1
, so that oil
9
attached on the ceiling
53
can readily drip therefrom. The protrusion
54
is positioned above the valve operating cam
29
and the slipper
35
where they make sliding contact with each other, so that the sliding parts are lubricated by the dripping oil
9
.
In the cylinder head
4
, a gas-liquid separation chamber
43
is provided separately from the chain chamber
51
. Another gas-liquid separation chamber
45
is provided in the rocker cover
5
and is communicated to the gas-liquid separation chamber
43
via a lead valve
44
. The gas-liquid separation chamber
45
is connected to an air cleaner
47
via a blow-by passage
46
. The air cleaner
47
is connected to an intake port
49
in the cylinder head
4
via a carburetor
48
.
The gas-liquid separation chambers
43
,
45
are provided for separating a mist of the oil
9
from a blow-by gas as the blow-by gas stored in the crank chamber
8
is recirculated to the air cleaner
47
. In the illustrated engine, the gas-liquid separation chamber
43
is opened to the chain chamber
50
, which is provided separately from the cylinder bore
18
. Thus, a gas inlet
52
is provided at the upper end portion of the chain chamber
50
of the cylinder block
2
, and the blow-by gas, which has flowed into the chain chamber
50
, flows into the gas-liquid separation chamber
43
via the gas inlet
52
. As the blow-by gas flows through the gas-liquid separation chamber
43
, the oil mist contained therein attaches to the wall surface of the gas-liquid separation chamber
43
, thereby separating the oil mist from the blow-by gas. The oil component, which has been separated in the gas-liquid separation chamber
43
, returns to the oil pan
10
via the wall surfaces of the gas-liquid separation chamber
43
and then to the chain chamber
50
.
The blow-by gas, which has flowed into the rocker cover
5
via the lead valve
44
, is subjected to a further oil mist separation process in the gas-liquid separation chamber
45
. Specifically, the oil mist contained in the blow-by gas, which has entered the gas-liquid separation chamber
45
, attaches to the wall surface of the gas-liquid separation chamber
45
, thereby achieving a further gas-liquid separation. Moreover, an oil return hole (not shown) may be provided in the bottom surface of the rocker cover
5
, whereby the oil
9
, which has attached to the wall surface of the gas-liquid separation chamber
45
, flows into the chain chambers
51
and
50
through the oil return hole and returns to the oil pan
10
via the wall surface of the chain chambers
51
and
50
.
The present invention has been specifically described above with respect to a particular embodiment thereof. It is understood, however, that the present invention is not limited to the above-described embodiment, but rather various modifications can be made thereto without departing from the scope and spirit of the present invention.
For example, the rib walls
63
may be formed in a conical shape or planar shape in parallel to the crankcase mounting face instead of the spherical shape.
While the present invention is applied to an inclined type of engine in the embodiment described above, it is of course possible to apply the present invention to a normal engine in which the cylinder axis is arranged in the gravitational direction. Moreover, while the present invention is applied to an air-cooled engine with a single-cylinder, the present invention may alternatively be applied to an air-cooled engine with a multi-cylinder, or a liquid-cooled engine with a single- or multi-cylinder.
While the cylinder block
2
and the crank case
3
are formed integrally with each other in the embodiment described above, they may alternatively be provided separately, and the cylinder head
4
and the cylinder block
2
may be formed integrally with each other.
In addition, while the timing system
30
is provided by using the sprockets
31
and
32
and the chain
33
in the embodiment described above, the timing system
30
may alternatively be provided by using other driving members known in the art, such as a cogged pulley and a cogged belt, or a timing pulley and a timing belt.
Moreover, in the present invention, the term “rotation” has a general concept including a circular motion in both directions, i.e. a clockwise direction and a counterclockwise direction, not a circular motion in only one direction.
According to the bearing case of the present invention, rib walls are formed between the bearing holder and the crankcase mounting section, so that a force radially exerted to the bearing holder is received by these rib walls, whereby the rigidity of the bearing case is improved. Accordingly, the bearing holder is less likely to deform, and the crankcase mounting section is subjected to less moment, allowing for less play thereof.
As a result, damage to the gasket caused by deformation or play of the bearing case is prevented, whereby the lifetime and reliability of the product are improved.
The rib walls are formed in a spherical shape so as to further enhance the rigidity of the bearing case, while the thickness of the rib walls can be reduced to make the bearing case more lightweight. Vibration and operation noise can also be absorbed and restricted more efficiently, resulting in overall enhancement of the product performance.
Moreover, cavities are formed in the bearing case on the lower side with respect to the axis of the crankshaft so as to form part of the oil pan for the engine, whereby the rigidity of the bearing case is further improved while the oil reservoir capacity is secured.
Furthermore, a reinforcing rib is formed on the outer side face of the crankcase mounting section, so that the rigidity of the crankcase in a surface direction is secured.
In particular, the reinforcing rib is formed to a portion where the rib walls exist, thus contributing to enhancement of the surface rigidity together with the rib walls, thereby improving rigidity of the bearing case.
While there have been described what are at present considered to be preferred embodiments of the present invention, it will be understood that various modifications may be made thereto, and it is intended that the appended claims cover all such modifications as fall within the true spirit and scope of the invention.
Claims
- 1. A bearing case attached to a crankcase of an engine for holding a bearing for supporting a crankshaft of said engine, comprising:a bearing holder for holding said bearing; a crankcase mounting section formed on an outer peripheral surface of said bearing case to be joined to said crankcase; and a rib wall formed in said bearing case on a side of said crankcase and extending between said bearing holder and said crankcase mounting section.
- 2. The bearing case according to claim 1, wherein said rib wall is formed in a spherical shape.
- 3. The bearing case according to claim 1, wherein said rib wall is formed on an upper side of the bearing case with respect to an axis of said crankshaft.
- 4. The bearing case according to claim 3, wherein a cavity is formed on a lower side of said bearing case with respect to said axis of the crankshaft, the cavity opening toward the side of said crankcase and forming part of an oil pan for said engine.
- 5. The bearing case according to claim 1, further comprising:a reinforcing rib formed along the outer periphery of said bearing case on one surface of said crankcase mounting section on the opposite side from said crankcase.
- 6. The bearing case according to claim 3, further comprising:a reinforcing rib formed along the outer periphery of said bearing case on one surface of said crankcase mounting section on the opposite side from said crankcase.
- 7. The bearing case according to claim 5, wherein said crankcase mounting section includes a plurality of bolt holes for passing a plurality of bolts therethrough so as to fixedly couple said bearing case to said crankcase, said reinforcing rib being formed so as to connect said plurality of bolt holes.
- 8. The bearing case according to claim 6, wherein said crankcase mounting section includes a plurality of bolt holes for passing a plurality of bolts therethrough so as to fixedly couple said bearing case to said crankcase, said reinforcing rib being formed so as to connect said plurality of bolt holes.
- 9. The bearing case according to claim 5, wherein the reinforcing rib is formed at a part of the bearing case where said rib wall exists.
- 10. The bearing case according to claim 7, wherein the reinforcing rib is formed at a part of the bearing case where said rib wall exists.
Priority Claims (1)
Number |
Date |
Country |
Kind |
2000-150853 |
May 2000 |
JP |
|
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