Title of Invention

OVERHEAD VALVE ENGINE

Abstract An overhead valve engine comprises a tappet guide hole (6) inducted downwardly from a bottom wall (5) of a push-rod insertion chamber (4) and a valve operating cam (7) arranged below the tappet guide hole (6), which guides an up-and-down movement of a tappet (8) placed on the valve operating cam (7). A push rod (9) is inserted through a push-rod insertion chamber (4) and a push-rod insertion hole (2) in series. An oil flow-out hole (11) is provided from the bottom wall (5) of the push-rod insertion chamber (4) into a crank case (10) . In this overhead valve engine, the oil flow-out hole (11) has an outlet (11a) arranged above a cam face of the valve operating cam (7) , so that oil (12) flowed out of the outlet (11a) of the oil flow-out hole (11) falls on the cam face of the valve operating cam (7).
Full Text

SPECIFICATION Title: OVERHEAD VALVE ENGINE
BACKGROUND OF THE INVENTION
1. Technical Field of the Invention
The present invention relates to an overhead valve engine and more particularly to an overhead valve engine which can enhance the lubrication efficiency of each of the valve operating cam and the tappet,
2. Description of Related Art
An example of the conventional overhead valve engines provides a push-rod insertion hole in a cylinder head and a push-rod insertion chamber in a cylinder block as well as the present invention. The push-rod insertion hole is communicated with the push-rod insertion chamber. The push-rod insertion chamber has a bottom wall, from which a tappet guide hole is inducted downwards. A valve operating cam is arranged below the tappet guide hole. The tappet guide hole guides an up-and-down movement of a tappet placed on the valve operating cam. A push rod placed on the tappet is inserted through the push-rod insertion chamber and the push-rod insertion hole in series. An oil flow-out hole is provided from the bottom wall of the push-rod insertion chamber into a crank case. There is Patent Public Disclosure No. 2001-263030 (see Fig. 2) as such a conventional technique. The overhead valve engine of this type can pass

the oil supplied onto the cylinder head through the push-rod insertion hole, the push-rod insertion chamber and the oil flow-out hole in the mentioned order and return it to an oil pan via the interior area of the crank case.
However, the conventional overhead valve engine arranges an outlet of the oil flow-out hole at a position away from just above a cam face of the valve operating cam. Therefore, the oil flowed out of the oil flow-out hole does not fall on the cam face of the valve operating cam to result in causing a problem.
The conventional technique has the following problem.
The valve operating cam is lubricated to a low degree as well as the tappet.
Since the oil which flows out of the outlet of the oil flow-out hole does not fall on the cam face of the valve operating cam, it is not utilized for lubricating the valve operating cam and the tappet. These valve operating cam and tappet are lubricated only by oil mist present within the crank case. Accordingly, they are lubricated to a low degree with the result of being readily worn off.
SUMMARY OF THE INVENTION
The present invention has an object to provide an overhead valve engine capable of solving the above-mentioned problem and particularly an overhead valve engine which can enhance the lubrication efficiency of each of the valve operation cam and the tappet.
The invention as set forth in claim 1 has the following characteristic matter.
An overhead valve engine, as exemplified in Fig. 1, comprises a cylinder head 1 provided with a push-rod insertion hole 2 and a cylinder block 3 formed with a

push-rod insertion chamber 4. The push-rod insertion hole 2 is communicated with the push-rod insertion chamber 4.
As shown in Fig. 4 (A) or Fig. 5 (A) , the push-rod insertion chamber 4 has a bottom wall 5, from which a tappet guide hole 6 is inducted downwards. A valve operating cam is arranged below the tappet guide hole 6. This tappet guide hole 6 guides the up-and-down movement of a tappet 8 placed on the valve operating cam 7. A push rod 9 placed on the tappet 8 is inserted through the push-rod insertion chamber 4 and the push-rod insertion hole 2 in series. An oil flow-out hole 11 is provided from the bottom wall of the push-rod insertion chamber 4 into a crank case 10.
In this overhead valve engine, as illustrated in Fig. 4(A) or Fig. 5(A), an outlet 11a of the oil flow-out hole 11 is arranged above a cam face of the valve operating cam 7, so that the oil 12 flowed out of the outlet 11a of the oil flow-out hole 11 can fall on the cam face of the valve operating cam 7.
On the assumption that a direction where a crank shaft 13 spans is taken as a front and rear direction and that a widthwise direction of the cylinder block is deemed as a left and right (lateral) direction, as shown in Fig. 3, there is provided a side water passage 15 that extends in the front and rear direction laterally of a cylinder 14. Cooling water 16 which flows out of a radiator is introduced into a cylinder jacket 17 through the side water passage 15. The oil flow-out hole 11 has a peripheral wall 18 opposed to the side water passage 15.
Effect of the Invention (Invention of Claim 1) The valve operating cam is lubricated to a high

degree as well as the tappet.
As exemplified in Fig. 4 (A) or Fig. 5 (A) , the outlet 11a of the oil flow-out hole 11 is arranged above the cam face of the valve operating cam 7, so that the oil 12 which flows out of the outlet 11a of the oil flow-out hole 11 can fall on the cam face of the valve operating cam 7. Thus the valve operating cam 7 and the tappet 8 are highly lubricated with the result of being hardly worn off.
The oil is supplied to the cam face of the valve operating cam with a viscosity suitable for lubrication.
As shown in Fig. 3, the oil flow-out hole 11 has the peripheral wall 18 opposed to the side water passage 15, Accordingly, the oil 12 flowed out of the oil flow-out hole 11 is cooled by the cooling water 16 passing through the side water passage 15 and is fed to the cam face of the valve operating cam 7 with a viscosity suited for lubrication. (Invention of Claim 2)
It offers the following effect in addition to the effect presented by the invention of claim 1. The valve operating cam is lubricated efficiently as well as the tappet.
As illustrated in Fig. 4(A) or Fig. 5(A), when the valve operating cam 7 exists at a position before it pushes up the tappet 8, a push-up face 21 of the valve operating cam 7 opposes to the outlet 11a of the oil flow-out hole 11 from below the outlet 11a, so that the oil 12 flowed out of the outlet 11a of the oil flow-out hole 11 can fall on the push-up face 21 of the valve operating cam 7. Thus the oil 12 is supplied to the push-up face 21 of the valve operating cam 7, at which contact pressure becomes highest, thereby enabling the valve operating cam 7 and the tappet 8 to be lubricated

efficiently.
(Invention of Claim 3)
It offers the following effect in addition to the effect presented by the invention of claim 1 or claim 2. The oil flows into the oil flow-out hole efficiently.
As exemplified in Figs. 4 (A) and 4 (B) or Fig. 5 (A) , the tappet guide hole 6 is provided at a peripheral edge portion of its upper opening with a guide groove 22. This guide groove 22 guides oil 2 3 overflowed from the upper opening of the tappet guide hole 6 to the oil flow-out hole 11. Therefore, this can flow the oil 23 overflowed from the upper opening of the tappet guide hole 6 into the oil flow-out hole 11 efficiently.
(Invention of Claim 4)
It offers the following effect in addition to the effect presented by any one of the inventions as set forth in claims 1 to 3. The oil can be cooled efficiently.
As shown in Fig. 3, an oil flow-out hole 11 is provided between the tappet guide hole 6 and the side water passage 15. Disposed between a pair of front and rear oil flow-out holes 11, 11 is a water passage outlet 24 which is directed from the side water passage 15 to the cylinder jacket 17. The oil flow-out hole 11 has the peripheral wall 18 opposed to both of the side water passage 15 and the water passage outlet 24. This increases a heat radiation area of the peripheral wall 18 of the tappet guide hole 6, thereby efficiently cooling the oil passing through the tappet guide hole 6.
(Invention of Claim 5)
It offers the following effect in addition to the effect presented by any one of the inventions set forth in claims 1 to 5.

The oil is efficiently cooled.
As exemplified in Fig. 5(A), the side water passage 15 has a wall 25 curved to project in a direction away from the cylinder 14. And the oil flow-out hole 11 is formed to curve along this curved wall 25. This curved wall 25 comes to the peripheral wall 18 of the oil flow-out hole 11, thereby increasing the heat radiation area of the peripheral wall 18 of the tappet guide hole 6 to result in efficiently cooling the oil passing through the tappet guide hole 6. (Invention of Claim 6)
It offers the following effect in addition to the effect presented by the invention of claim 5. The oil is efficiently fed to the cam face of the valve operating cam.
As exemplified in Figs. 5(A) and 5(B), an outlet portion 26 of the oil flow-out hole 11 is formed below the side water passage 15 in the left and right direction, a guiding notch portion 27 is provided at a lower portion of an outlet peripheral wall, so that the oil 12 flowed out of the outlet of the oil flow-out hole 11 is guided by the guiding notch portion 27 to the cam face of the valve operating cam 7. In consequence, the oil of the oil flow-out hole 11 is efficiently supplied to the cam face of the valve operating cam 7. (Invention of Claim 7)
It offers the following effect in addition to the effect presented by any one of claims 1 to 6. It remarkably appears that the valve operating cam and the tappet are lubricated with improved efficiency.
As exemplified in Fig. 4(A) or Fig. 5(A), in the case where the valve operating cam 7 is arranged on a right upper side of the crank shaft 13 and on a right lateral side of the cylinder 14 with the tappet 8

disposed on an upper portion of the valve operating cam 7, in an engine which takes a rotation direction 20 of the crank shaft 13 as a clockwise direction, there is no probability that the oil which leaks out of the crank shaft 13 is splashed onto the valve operating cam 7. Thus if the present invention is applied to the engine of this type in which the valve operating cam 7 and the tappet 8 are hardly supplied with oil, it remarkably appears that the valve operating cam 7 and the tappet 8 are lubricated with improved efficiency.
BRIEF DESCRIPTION OF THE DRAWINGS
Fig. 1 is a front view in vertical section of an engine according to a first embodiment of the present invention;
Fig. 2 is a plan view of a cylinder block to be used for the engine shown in Fig. 1 ;
Fig. 3 is a plan view in cross section of the cylinder block shown in Fig. 2;
Fig. 4(A) is a sectional view taken along a line VI-VI in Fig. 3;
Fig. 4(B) is a sectional view taken along a line B-B in Fig. 4(A);
Fig. 5(A) shows a engine according to a second embodiment and is similar to Fig. 4(A); and
Fig. 5(B) is a sectional view taken along a line B-B.
DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS
The present invention is explained based on the attached drawings.
Figs 1 to 4 are views showing an overhead valve engine according to a first embodiment of the present invention. In this embodiment, explanation is made by using a multi-cylinder vertical overhead valve engine of

water-cooled type.
This engine is outlined as follows.
As shown in Fig. 1, it is provided with a cylinder block 3. The cylinder block 3 comprises an upper cylinder 14 and a lower crank case 10 which are formed into an integral structure. The cylinder 14 is surrounded by a cylinder jacket 17. A cylinder head 1 is assembled to an upper portion of the cylinder block 3. A head cover 28 is assembled to an upper portion of the cylinder head 1. An oil pan 29 is assembled to a lower portion of the crank case 10. The cylinder head 1 is formed with an intake port 30 and an exhaust port 31. These port holes are opened and closed by an intake valve 32 and an exhaust valve (not shown) . The intake vale 32 and the exhaust valve are opened and closed by a valve operating device.
The valve operating device is constructed as follows.
As shown in Fig. 1, a valve operating cam 7 is arranged within a crank case 1. The head cover 28 accommodates a rocker arm 33. The cylinder head 1 is provided with a push-rod insertion hole 2, and the cylinder block 3 is provided with a push-rod insertion chamber 4. The push-rod insertion hole 2 is communicated with the push-rod insertion chamber 4. As shown in Fig. 4 (A) , a tappet guide hole 6 is downwardly inducted from a bottom wall 5 of the push-rod insertion chamber 4. The valve operating cam 7 is arranged below the tappet guide hole 6. The tappet guide hole 6 guides an up-and-down movement of a tappet 8 placed on the valve operating cam 7. A push rod 9 disposed on the tappet 8 is inserted through the push-rod insertion chamber 4 and the push-rod insertion hole 12 in series. As shown in Fig. 1, the rocker arm 33 has an input portion brought into butting contact with an upper end of the push rod 9.

A lubricating structure of the valve operating device is as follows.
As shown in Fig. 4(A), an oil flow-out hole 11 is provided from the bottom wall 5 of the push-rod insertion chamber 4 into the crank case 10. The oil flow-out hole 11 has an outlet 11a arranged above a cam face of the valve operating cam 7, so that oil 12 flowed out of the outlet 11a of the oil flow-out hole 11 falls on the cam face of the valve operating cam 7. Concretely speaking, when the valve operating cam 7 is at a position before it pushes up the tappet 8, the valve operating cam 7 has a push-up face 21 opposed to the outlet 11a of the oil flow-out hole 11 from therebelow, so that the oil 12 flowed out of the outlet 11a of the oil flow-out hole 11 falls on the push-up face 21 of the valve operating cam 7. Further, as shown in Fig. 4(B), the tappet guide hole 6 is provided at a peripheral edge portion of its upper opening with a guide groove 22. This guide groove 22 guides oil 23 overflowed from the upper opening of the tappet guide hole 6 to the oil flow-out hole 11. The oil flow-out hole 11 is formed beside the tappet guide hole 6. The oil 12 flowed out of the outlet 11a of the oil flow-out hole 11 passes by the tappet 8 and falls on the push-up face 21 at a cam nose (a portion projecting radially of a basic circle) of the valve operating cam 7.
A cooling structure of the oil is as follows.
On the assumption that a direction where a crank shaft 13 spans is taken as a front and rear direction and that a widthwise direction is deemed as a left and right (lateral) direction, as shown in Fig. 3, there is provided laterally of the cylinder 14 a side water passage 15 extending in the front and rear direction. Cooling water 16 which flows out of a radiator is introduced into the cylinder jacket 17 through the side

water passage 15. The oil flow-out hole 11 has a peripheral wall 18 opposed to the side water passage 15. Concretely speaking, an oil flow-out hole 11 is provided between the tappet guide hole 6 and the side water passage 15. Provided between a pair of front and rear oil flow-out holes 11, 11 is a water passage outlet 24 directed from the side water passage 15 to the cylinder jacket 17. Thus the oil flow-out hole 11 has the peripheral wall 18 opposed to both of the side water passage 15 and the water passage outlet 24.
The engine of a second embodiment shown in Fig. 5 differs from the first embodiment on the following points.
As shown in Fig. 5(A), the side water passage 15 has a wall 25 curved to project in a direction away from the cylinder 14. The oil flow-out hole 11 is formed to curve along this curved wall 25. An outlet portion 26 of the oil flow-out hole 11 is formed below the side water passage 15 in the left and right direction. A guiding notch portion 27 is provided at a lower portion of an outlet peripheral wall, so that the oil 12 flowed out of the outlet 11a of the oil flow-out hole 11 is guided by the guiding notch portion 27 to the cam face of the valve operating cam 7.
The other structure is the same as that of the first embodiment. In Fig. 5, the same elements as those in the first embodiment are designated by the same numerals.
Further, this engine, in either of the first embodiment and the second embodiment, as shown in Fig. 4(A) and Fig. 5(A), takes a rotation direction 20 of the crank shaft 13 as a clockwise direction in the case where when seen in a direction parallel to a center axis 19 of the crank shaft 13, the cylinder 14 is directed in an upper and lower direction, and the valve operating

cam 7 is arranged at a right upper side of the crank shaft 13 and on a right lateral side of the cylinder 14 with the tappet 8 placed on the upper portion of the valve operating cam 7.







(Claims)
1. An overhead valve engine comprising a cylinder
head (1) provided with a push-rod insertion hole (2) and
a cylinder block (3) formed with a push-rod insertion
chamber (4), the push-rod insertion hole (2) being
communicated with the push-rod chamber (4),
a tappet guide hole (6) being downwardly inducted from a bottom wall (5) of the push-rod insertion chamber (4), a valve operating cam 7 being arranged below the tappet guide hole (6), which guides an up-and-down movement of the tappet (8) placed on the valve operating cam (7), a push rod (9) disposed on the tappet (8) being inserted through the push-rod insertion chamber (4) and the push-rod insertion hole (2) in series, an oil flow-out hole (11) being provided from the bottom wall (5) of the push-rod insertion chamber (4) into a crank case (10) , wherein
the oil flow-out hole (11) has an outlet (11a) arranged above a cam face of the valve operating cam (7), so that oil (12) flowed out of the outlet (11a) of the oil flow-out hole (11) falls on the cam face of the valve operating cam (7), and
on the assumption that a direction where a crank shaft (3) spans is taken as a front and rear direction and that a widthwise direction of the cylinder block (3) is deemed as a left and right (lateral) direction, there is provided laterally of the cylinder (14) a side water passage 15 extending in the front and rear direction, and cooling water (16) which flows out of a radiator is introduced into a cylinder jacket (17) through the side water passage (15), the oil flow-out hole (11) having a peripheral wall (18) opposed to the side water passage (15) .
2. The overhead valve engine as set forth in claim
1, wherein

when the valve operating cam (7) is at a position before it pushes up the tappet (8), the valve operating cam (7) has a push-up face (21) opposed to the outlet (11a) of the oil flow-out hole (11) from therebelow, so that the oil (12) flowed out of the outlet (11a) of the oil flow-out hole (11) falls on the push-up face (21) of the valve operating cam (7).
3. The overhead valve engine as set forth in claim
1 or claim 2, wherein
the tappet guide hole (6) is provided, at a peripheral edge portion of its upper opening, with a guide groove (22) , and this guide groove (22) guides oil (23) overflowed from the upper opening to the oil flow-out hole (11).
4. The overhead valve engine as set forth in any
one of claims 1 to 3, wherein
an oil flow-out hole (11) is provided between the tappet guide hole (6) and the side water passage (15), and disposed between a pair of front and rear oil flow-out holes (11), (11) is a water passage outlet (24) directed from the side water passage (15) to the cylinder jacket (17), the oil flow-out hole (11) having a peripheral wall (18) opposed to both of the side water passage (15) and the water passage outlet (24).
5. The overhead valve engine as set forth in any
one of claims 1 to 4, wherein
the side water passage (15) has a wall (25) curved to project in a direction away from the cylinder (14) and the oil flow-out hole (11) is formed to curve along the curved wall (25).
6. The overhead valve engine as set forth in claim
5, wherein
an outlet portion (26) of the oil flow-out hole (11) is formed below the side water passage (15) in the left and right direction, and a guiding notch portion

(27) is provided at a lower portion of an outlet peripheral wall and guides the oil (12) flowed out of the outlet (11a) of the oil flow-out hole (11) to the cam face of the valve operating cam (7).
7. The overhead valve engine as set forth in any one of claims 1 to 6, wherein
a rotation direction (2 0) of the crank shaft (13) is made to be taken as a clockwise direction in the case where when seen in a direction parallel to a center axis (19) of the crank shaft (13), the cylinder (14) is oriented in an up and down direction, and the valve operating cam (7) is arranged at a right upper side of the crank shaft (13) and on a right lateral side of the cylinder 14 with the tappet (8) placed on the valve operating cam (7).


Documents:

1167-che-2005 amended claims 07-04-2011.pdf

1167-CHE-2005 AMENDED PAGES OF SPECIFICATION 23-02-2011.pdf

1167-CHE-2005 AMENDED CLAIMS 23-02-2011.pdf

1167-CHE-2005 CORRESPONDENCE OTHERS 07-04-2011.pdf

1167-CHE-2005 EXAMINATION REPORT REPLY RECEIVED 23-02-2011.pdf

1167-CHE-2005 FORM-13 07-04-2011.pdf

1167-che-2005 form-3 23-02-2011.pdf

1167-CHE-2005 OTHER PATENT DOCUMENT 23-02-2011.pdf

1167-CHE-2005 POWER OF ATTORNEY 23-02-2011.pdf

1167-CHE-2005 FORM 18.pdf

1167-che-2005-abstract.pdf

1167-che-2005-claims.pdf

1167-che-2005-correspondnece-others.pdf

1167-che-2005-description(complete).pdf

1167-che-2005-drawings.pdf

1167-che-2005-form 1.pdf

1167-che-2005-form 26.pdf

1167-che-2005-form 3.pdf

1167-che-2005-form 5.pdf


Patent Number 247781
Indian Patent Application Number 1167/CHE/2005
PG Journal Number 20/2011
Publication Date 20-May-2011
Grant Date 18-May-2011
Date of Filing 22-Aug-2005
Name of Patentee KUBOTA CORPORATION
Applicant Address 2-47, SHIKITSUHIGASHI 1-CHOME, NANIWA-KU, OSAKA-SHI OSAKA
Inventors:
# Inventor's Name Inventor's Address
1 IWANAGA, WATARU C/O KUBOTA CORP., SAKAI-RINKAI FACTORY 8, CHIKKO SHINMACHI,SAKAI-SHI OSAKA.
2 ANAMI, HIROYUKI C/O KUBOTA CORP., SAKAI-RINKAI FACTORY 8, CHIKKO SHINMACHI,SAKAI-SHI OSAKA, JAPAN
PCT International Classification Number F01M 9/10
PCT International Application Number N/A
PCT International Filing date
PCT Conventions:
# PCT Application Number Date of Convention Priority Country
1 2004-241967 2004-08-23 Japan