Pumps – Motor driven – Electric or magnetic motor
Reexamination Certificate
2000-01-19
2001-08-28
Walberg, Teresa (Department: 3742)
Pumps
Motor driven
Electric or magnetic motor
Reexamination Certificate
active
06280158
ABSTRACT:
BACKGROUND OF THE INVENTION
1. Field of the Invention
The present invention relates to a water pump for circulating the cooling water of an internal combustion engine. In particular, the present invention relates to a water pump for circulating the cooling water of an internal combustion engine which includes a water passage for connecting a water pump which is connected to one end of and driven by a cam shaft for a valve system arranged in a cylinder head to a cooling water passage in a cylinder block. With this arrangement, manufacturing costs can be reduced.
The present invention also relates to a mounting structure of a camshaft in an overhead valve (OHV) type internal combustion engine.
2. Description of Related Art
A conventional water pump for circulating cooling water of an internal combustion engine is known from Japanese Patent Publication No. 2,782,548, wherein the water pump is mounted on a cylinder head body and a water passage communicating with a delivery port of the water pump is formed in a cylinder head. Furthermore, the water passage communicates with a cooling water passage (water jacket) in a cylinder block to introduce cooling water into the cooling water passage.
In addition, a conventional water pump for circulating the cooling water of an internal combustion engine is known, wherein instead of foaming the water passage communicating with the delivery port of the water pump in the cylinder head, a hose communicating with the cooling water passage in the cylinder block is used to introduce cooling water into the cooling water passage.
However, in the conventional water pump for circulating the cooling water of an internal conventional engine, the water passage needs to be formed in a cylinder head so as to make the delivery plot of the water pump communicate with the cooling water passage in the cylinder block. In the case where a hose is used instead of the water passage, the procedure of connecting the hose is troublesome. This results in an increase in the number of foaming processes and the number of assembling processes in both cases.
Conventionally, in an overhead valve type internal combustion engine, push rods having a long size are interposed between a camshaft which is close to a crank shaft and rocker arms for driving valves in order to transmit rotation of the crank shaft to open and close the valves disposed at an upper portion of a cylinder.
However, the push rods are not suitable for high speed rotation because of is heavy initial weights.
There is an example where the camshaft is separated away from the crank shaft so as to a-range the cam shaft in a central portion of a cylinder block (Japanese Unexamined Patent Publication No. Sho 63-125139).
The overhead valve type internal combustion engine
01
of the example described above is illustrated in
FIG. 8
of the present invention. A camshaft
015
is installed in the central portion of a cylinder block
03
interposed between a crank case
02
and a cylinder head
04
. Furthermore, a cam chain
018
is suspended between a cam sprocket
017
of the camshaft
015
and a timing sprocket
016
of a crank shaft
08
.
Push rods
024
brought into contact, at their lower ends, with cam followers
020
which rock by coming into contact with cam surfaces of the camshaft are extended upward, penetrate the cylinder head
04
, and reach a cylinder head cover
05
, whereby upper ends of the push rods rock the rocker arms.
Accordingly, when reciprocating motion of a piston
06
rotates the crank shaft
08
via a connecting rod
07
, the camshaft
015
within the cylinder block
03
is rotated via the cam chain
018
and the cam followers
020
are rocked. The rocking motion of the cam followers
020
moves the push rods
024
up and down, and opens and closes the valves at prescribed timings via the rocker arms.
In the example stated above, the cam shaft
015
is located within the cylinder block
03
so as to come closer to the rocker arms disposed on the upper side than in the case of the general overhead valve type internal combustion engine where the camshaft is located within the crank case, to thereby shorten the lengths of the push rods
024
.
Therefore, the inertial weights of the push rods
024
are smaller than those of the general type engine, so that the mounting structure for the camshaft illustrated in the example is applicable to a certain degree of high speed rotation.
However, the push rods
024
still have a long size, since the push rods
024
penetrate the cylindrical head
04
and lower ends thereof reach the vicinities of the central portions of the cylinder block
03
. Therefore, the inertial weights of this type of the push rods
024
remarkably influence on high speed rotation.
Furthermore, since the camshaft
015
is disposed at the central portion within the cylinder block
03
, in the case where the cams are required to be replaced due to maintenance or the like, the cylinder block
03
must be removed on account of the necessity of removing the cam chain, and therefore it is not easy to replace the cams.
SUMMARY OF THE INVENTION
It is the object of the present invention to provide a water pump for circulating the cooling water of an internal combustion engine which can solve the above described problems of the conventional water pump. Specifically, it is an object of the present invention to provide a water pump which can facilitate the formation of the water passage connecting the water pump to the cooling water passage in the cylinder block and which can reduce manufacturing costs.
The present invention relates to a water pump for circulating the cooling water of an internal combustion engine which can solve the problems described above. According to a first aspect of the present invention, a water pump for circulating the cooling water of an internal combustion engine is connected to one end of a cam shaft for a valve system arranged in a cylinder head. The water pump is driven by the cam shaft and the delivery port of the water pump is extended near a cooling water supply port formed in the side wall of a cylinder block and is connected to a cooling water passage in the cylinder block.
The first aspect of the present invention is constituted in a manner described above, and the delivery port of the water pump which is connected to one end of a cam shaft for a valve system and is driven by the cam shaft is extended near to a cooling water supply port formed in the side wall of the cylinder block and is connected to the cooling water supply port.
As a result, the number of processes for foaming a water passage for connecting the water pump to the cooling water passage in the cylinder block and the number of assembling processes can be reduced. Furthermore, piping such as a hose for connecting the delivery port of the water pump to the cooling water supply port formed in the side wall of the cylinder block can be reduced to a minimum. This can facilitate the formation of the water passage for connecting the water pump to the cooling water passage in the cylinder block and can reduce manufacturing costs.
In addition to the first aspect of the present invention, the present invention according to a second aspect includes the delivery port of the water pump extended to a position directly opposite to the cooling water supply port formed in the side wall of the cylinder block and the delivery port is connected to the cooling water supply port with a connection pipe.
As a result, the delivery port of the water pump can be connected to the cooling water supply port formed in the side wall of the cylinder block with a short straight pipe, which can simplify the connection structure thereof.
It is also an object of the present invention to provide a mounting structure of the camshaft which is capable of applying the structure to high speed rotation by shortening the lengths of the push rods as well as facilitating maintenance such as the replacement of the cams.
In order to achieve the object mentioned above, an overhead valve type internal combustion engine includes the camshaf
Fujimoto Yasushi
Itoh Katsuhiko
Kimura Yoshihiro
Shichinohe Takashi
Birch & Stewart Kolasch & Birch, LLP
Honda Giken Kogyo Kabushiki Kaisha
Patel Vinod D.
Walberg Teresa
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