Internal-combustion engines – Frame construction – Horizontal cylinder
Reexamination Certificate
2002-03-19
2004-01-20
Yuen, Henry C. (Department: 3747)
Internal-combustion engines
Frame construction
Horizontal cylinder
Reexamination Certificate
active
06679220
ABSTRACT:
BACKGROUND OF THE INVENTION
1. Field of the Invention
The present invention relates to a multi-cylinder engine.
2. Description of Prior Art
There is the following engine as a conventional example of the multi-cylinder engine.
An inter-cylinder wall has an upper side portion provided on its left and right both sides with inter-cylinder bosses. The inter-cylinder bosses are connected to left and right both sides of a lower side portion of the inter-cylinder wall in continuity therewith. An upper female screw is provided in one of the inter-cylinder bosses. A head bolt engages with the upper female screw in screw-thread attachment. A bearing wall of a crank shaft is formed so that it can be divided into an upper wall portion and a lower wall portion. The upper wall portion is connected to a cylinder block and has left and right both sides provided with upper wall bosses. These upper wall bosses have upper end portions connected to the left and right both sides of the lower side portion of the inter-cylinder wall in continuity therewith. A lower female screw is provided in one of the upper wall bosses. A bearing bolt engages with the lower female screw in screw-thread attachment to assemble the lower wall portion to the cylinder block.
As for this type of engine, a gas pressure produced in a combustion chamber raises up a cylinder head and lowers the lower wall portion. This results in raising the upper female screw by the head bolt and lowering the lower female screw through the bearing bolt.
However, this type of engine generally has the upper female screw and the lower female screw formed in an outer wall of the cylinder block.
The foregoing conventional technique has the following problems.
“Problem 1”
The Outer Wall of the Cylinder Block Readily Vibrates
The upper female screw and the lower female screw are formed in the outer wall of the cylinder block. Therefore, the outer wall of the cylinder block extends and easily vibrates with the gas pressure produced in the combustion chamber. This enlarges the engine's noise and shortens its useful life.
In order to solve the problem 1, like the present invention, it is effective to interpose an inner space
17
between the upper and lower female screws
9
,
13
and the outer wall
14
of the cylinder block
16
as shown in FIG.
1
. However, in this case, the gas pressure with which the outer wall
14
of the cylinder block
6
is burdened acts on the left and right both sides
2
c
,
2
c
of the lower side portion
2
b
of the inter-cylinder wall
2
as well as on lower left and right peripheral wall portions
15
,
15
of a cylinder wall
1
in continuity with them in the front and rear direction. Therefore, in the event each of these portions has a reduced thickness, there is a likelihood that the following new problem will occur.
“Problem 2”
The Lower Left and Right Peripheral Wall Portions of the Cylinder Wall Undergo a Large Strain
In the case where the lower left and right peripheral wall portions of the cylinder wall each has a reduced thickness, this portion undergoes a large strain to result in seizing a piston and producing a slap sound or the like.
SUMMARY OF THE INVENTION
The present invention has an object to provide a multi-cylinder engine capable of solving the above-mentioned problems.
A principal construction of the present invention is as follows.
As shown in
FIG. 1
, the inner space
17
is interposed between the upper and lower female screws
9
,
13
, which engage with the head bolt
8
and the bearing bold
12
in screw-thread attachment, respectively, and the outer wall
14
of the cylinder block
6
.
As shown in
FIGS. 3 and 4
, the lower left and right peripheral wall portions
15
,
15
of the cylinder wall
1
continue with the left and right both sides
2
c
,
2
c
of the lower side portion
2
b
of the inter-cylinder wall
2
in the front and rear direction. They increase their thicknesses progressively as they approach the left and right both sides
2
c
,
2
c.
The present invention offers the following effect.
“Effect 1”
The Outer Wall of the Cylinder Block Hardly Vibrates
As shown in
FIG. 1
, the inner space
17
is interposed between the upper and lower female screws
9
,
13
and the outer wall
14
of the cylinder block
6
. The gas pressure produced in the combustion chamber hardly extends and vibrates the outer wall
14
of the cylinder block
6
. This decreases the engine's noise and also elongates its useful life.
“Effect 2”
It is Possible to Inhibit the Strain of the Lower Left and Right Peripheral Wall Portions of the Cylinder Wall
As shown in
FIGS. 3 and 4
, the lower left and right peripheral wall portions
15
,
15
of the cylinder wall
1
continue with the left and right both sides
2
c
,
2
c
of the lower side portion
2
b
of the inter-cylinder wall
2
and increase their thicknesses gradually as they approach the left and right both sides
2
c
,
2
c
. Therefore, even if a large gas pressure acts on the lower left and right peripheral wall portions
15
,
15
of the cylinder wall
1
, it is possible to inhibit the strain of these portions with the result of prohibiting the seizure of the piston and the production of the slap sound or the like attributable to the strain of these portions.
“Effect 3”
It is Possible to Secure a Strength of the Lower Side Portion of the Inter-cylinder Wall
As shown in
FIG. 1
, a lowermost edge
20
of a transverse water passage
18
is arranged higher than a position
19
of a piston ring at the uppermost portion of a piston head positioned at a bottom dead center. This arrangement makes it possible to secure a full height of the lower side portion
2
b
of the inter-cylinder wall
2
and therefore surely obtain a strength of this portion.
“Effect 4”
It is Possible to Inhibit a Shear Strain of the Lower Side Portion of the Inter-cylinder Wall
As shown in
FIG. 1
, a pair of the vertically positioned head bolt
8
and bearing bolt
12
are arranged on the same axis
29
. This arrangement enables a pulling force the lower side portion of the inter-cylinder wall
2
receives to act on the same axis
29
, which results in the possibility of inhibiting a shear strain of the lower side portion
2
b
of the inter-cylinder wall
2
. This can prevent the seizure of the piston and the production of the slap sound or the like attributable to the shear strain of this portion.
“Effect 5”
Parts' Control is Facilitated and at the Same Time Parts' Cost is Reduced
As shown in
FIG. 1
, the head bolt
8
is made common with the bearing bolt
12
. This facilitates the control of bolts and reducing the cost for purchasing the bolts.
“Effect 6”
It is Possible to Effectively Utilize the Lower Side Portion of the Inter-cylinder Wall
As shown in
FIG. 1
, an oil supply passage
21
is made to pass a space defined between the upper female screw
9
and the lower female screw
13
. Owing to this arrangement, the lower side portion
2
b
of the inter-cylinder wall
2
can be effectively utilized as a wall for forming the oil supply passage
21
.
“Effect 7”
Chips Produced when Working Screws can be Inhibited from Entering the Oil Supply Passage
As shown in
FIG. 1
, the oil supply passage
21
does not communicate with either of the upper female screw
9
and the lower female screw
13
. This arrangement results in being able to inhibit the chips produced when working screws, from entering the oil supply passage
21
.
“Effect 8”
It is Possible to Effectively Utilize the Lower Side Portion of the Inter-cylinder Wall
As shown in
FIG. 1
, a hole
23
of an interlocking shaft
22
invades the lower side portion
2
b
of the inter-cylinder wall
2
between the upper female screw
9
and the lower female screw
13
. Owing to this arrangement, the lower side portion
2
b
of the inter-cylinder wall
2
can be effectively utilized for forming the hole
23
.
“Effect 9”
It is Possible to Produce Different Types of Engines Separately with Ease
As shown in
FIG. 1
, the cylinder block
6
can be divided into an upper block portion
6
a
and a lower block portion
Aketa Masahiro
Iwanaga Wataru
Shiraishi Yasunori
Watanabe Makoto
Bacon & Thomas PLLC
Benton Jason
Kubota Corporation
Yuen Henry C.
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