Source: http://www.allindianpatents.com/patents/204669-valve-gear-of-internal-combustion-engine
Timestamp: 2019-03-23 07:05:07
Document Index: 142704756

Matched Legal Cases: ['art 35', 'art 34', 'art 35', 'art 36', 'art 34', 'art 34', 'art 35', 'art 34', 'art 34', 'art 35', 'art, 35', 'art, 36', 'art, 37']

Indian Patents. 204669:VALVE GEAR OF INTERNAL COMBUSTION ENGINE
A valve gear for an internal combustion engine (1) in which out of suction and exhaust valves (16, 17), at least one valve (17) comprises not less than two poppet valves, characterized in that a rocker arm (30) is formed into a branched shape going round an ignition plug (38) on one valve side having not less than two poppet valves (17), and other valve (16) is directly driven to be opened and closed from a cam shaft (21).
"VALVE GEAR OF INTERNAL COMBUSTION ENGINE"
2 8 SEP 2001 GRANTED
The present invention relates to a valve gear of an internal combustion engine in which at least one of suction and exhaust valves comprises not less than two poppet valves.
There is a conventional valve gear of a 4-stroke cycle internal combustion engine wherein one valve of suction and exhaust valves is driven to be opened and closed through a rocker arm from a cam shaft, and the other valve is directly driven to be opened and closed from the cam shaft (Japanese Patent Application Laid-Open No. 5-133207 Publication).
According to the present invention there is provided an valve gear for an internal combustion engine in which out of suction and exhaust valves, at least one valve comprises not less than two poppet valves, characterized in that a rocker arm is formed into a branched shape going round an ignition plug on one valve side having not less than two poppet valves, and other valve is directly driven to be opened and closed from a cam shaft.
FIG. 1 is a longitudinal sectional side view of an
internal combustion engine provided with a valve gear according
FIG. 2 is a longitudinal sectional front view of the
internal combustion engine shown in FIG. 1.
FIG. 3 is a top view of the internal combustion engine with a cylinder head cover removed.
FIG. 4 is an enlarged perspective view of main parts of the valve gear.
One embodiment of the present invention shown in FIGS. 1 to 4 will be described hereinafter.
In a water cooling overhead valve spark ignition type single cylinder 4-cycle stroke internal combustion engine 1, a crank shaft 6 is mounted on a motorcycle not shown so as to be directed in the width direction, a cylinder block 3, a cylinder head 4 and a cylinder head cover 5 are sequentially placed on a crank case 2 as shown in FIG. 1, and the crank case 2, the cylinder block 3, the cylinder head 4 and the cylinder head cover 5 are connected integral with one another by means of bolts or the like not shown extending therethrough.
In the aforementioned valve gear, three suction poppet valves and two exhaust poppet valves are disposed per cylinder, a cam shaft provided with five cam crests per cylinder corresponding to 1 : 1 to each poppet valve is prepared, top ends of one three-suction poppet valves are placed in contact with three cam crests of the cam shaft, the other two-poppet valves are directly driven to be opened and closed the cam crests, and the other two-exhaust poppet valves are driven to be opened and closed by two cam crests of the cam shaft through two respective rocker arms. Therefore, many cam crests are necessary, two rocker arms are necessary going round an ignition plug, the number of parts increases, and the construction becomes complex, and there is a disadvantage in terms of productivity and costs.
[MEANS FOR SOLVING THE PROBLEM AND EFFECT] The present invention relates to an improvement in a valve gear of an internal combustion engine which overcomes these drawbacks. In an internal combustion engine in which at least one of suction and exhaust valves comprises not less than two poppet valves, a valve gear characterized in that a rocker arm is formed in the branched shape crossing an ignition plug on one valve side having said not less than two poppet valves, and other valve is directly driven to be opened and closed from a cam shaft.
The present invention being constituted as mentioned
above, in the poppet valve on the side driven to be opened and closed by the rocker arm, one cam crest is suffice, and one rocker arm is also suffice, the number of parts and the number of assembling steps are reduced, the valve gear becomes light-weighted, the construction can be simplified, and the considerable enhancement of productivity and cost down are achieved.
Further, since the rocker arm is branched and formed in a U- shape so as to go round the ignition plug, a nipping angle between one poppet valve and the other poppet valve'is smail, a combustion chamber enabling higher compression and higher combustion efficiency is constituted easily, and the performance of the internal combustion engine is materially enhanced.
The crank shaft 6 is pivotally supported on the crank case 2, a piston 8 is vertically slidably fitted in a cylinder bore 7 of the cylinder block 3, both ends of a connecting rod 11 are pivotally mounted on a piston pin 9 of the piston 8 and a crank pin 10 of the crank shaft 6, the piston 8 is pressed downward by combustion gases ignited intermittently by an ignition plug (see FIG. 3) 13 in the vicinity of a top dead center of the piston 8 within a combustion chamber 12 defined by a generally triangular (in section) depressed surface in the central part of the lower surface of the cylinder head 4, the cylinder bore 7 and the top surface of the piston 8, and the crank shaft 6 is driven to be rotated by that pressing force.
Further, a pair of left and right suction ports 14 are formed on the rear side (right side in FIG. 1) of the vehicle body of the cylinder head 4, a pair of left and right exhaust ports 15 are formed on the front side (left side in FIG. 1) of the vehicle body of the cylinder head 4, a suction poppet valve 16 and an exhaust poppet valve 17 for opening and closing openings of the suction port 14 and the exhaust port 15 are slidably fitted in a guide tube 18 at a small angle of a valve nipping angle, and valve springs 20 are disposed on lifers 37 (on the side of the suction poppet valve 16) and retainers 19 (on the side of the exhaust poppet valve 17) provided on the top ends of the suction poppet valve 16 and the exhaust poppet valve 17, and the top surface of the cylinder head 4, and the suction poppet valve 16 and the exhaust poppet valve 17 are
always closed by the spring force of the valve springs 20.
Furthermore, as shown in FIG. 2, a diecast cam shaft holder 25 for pivotally supporting the cam shaft 21 through a rolling bearing 39 so that the cam shaft 21 is parallel with the crank shaft 6 is mounted integral with the cylinder head 4 by bolts not shown, the cam shaft holder 25 having a plane shape formed in a generally U-shape, a drive sprocket 26 is fitted integrally on the left end (this side in FIGS. 3 and 4) of the cam shaft 21, an endless cam chain 28 is extended between a drive sprocket 27 fitted on the left side of the crank shaft 6 and the drive sprocket 26, the number of teeth of the drive sprocket 27 and the drive sprocket 26 is set to 2 : 1, and when the crank shaft 6 is rotated, the cam shaft 21 is rotated at a rotational speed of 1/2.
One mounting hole out of mounting hoes of the cam shaft holder 25 with respect to the cylinder head 4 serves as an oil passage, and lubricating oil is discharged towards the cam crests 22, 23, 24 of the cam shaft 21 from the oil passage of the cam shaft holder 25.
Further, as shown in FIG. 1, a rocker arm shaft 29 is positioned downward on the body front side (left side) with respect to the cam shaft 21 and fitted in the cam shaft holder 25, the rocker arm shaft 29 is, so as not to be come out and as to be locked by bolts not shown for mounting the cam shaft holder 25 to the cylinder head 4, partly stopped by bolts, a
rocker arm 30 is pivotally supported on the rocker arm shaft 29, a roller 33 is supported rotatably through a shaft 32 on a pair of left and right brackets 31 one end (vehicle body rear side) of the rocker arm 30, the other end of the rocker arm 30 is branched in a U-shape to left and right, both ends thereof are respectively placed in contact with the top end of the two exhaust poppet valves 17 positioned forward of the body (left side in FIG. 1), and a roller 33 on one end of the rocker arm 30 is placed in contact with the cam crest 22 in the central part of the cam shat 21 at a position forward of the body.
As shown in FIG. 1, a bottom part 35 is formed obliquely, forwardly and upwardly from the lower end of a wall part 34 at the rear of the body of the cam shaft holder 25, the bottom part 35 is formed with a tube part 36 capable of loosely receiving a lifter 37 of the suction poppet valve 16.
The cam crests 23, 24 positioned on both left and right sides of the body of the central cam crest 22 are, through the lifter 37, placed in contact with the top end of two suction poppet valve 16 positioned at the rear (right side in FIG. 1) of the body, and these cam crests 22, 23, 24 of the cam shaft 21 are respectively formed in the fixed shape so as to impart the suction characteristic and the exhaust characteristic adapted to the fixed operating circumstances of the water cooling overhead valve spark ignition type single cylinder 4-cycle stroke internal combustion engine 1 to the suction poppet valve 16 and the exhaust poppet valve 17.
Furthermore, as shown in FIG. 1, an ignition plug guide tube 38 is formed integral with the cylinder head 4 positioned in the approximately central position of the suction poppet valve 16 and the exhaust poppet valve 17 as viewed from the side and in the state being somewhat inclined forward, and the ignition plug 13 is detachably mounted on the lower end of the ignition plug guide tube 38. It is noted that the ignition plug guide tube 38 may be integrally pressed into the cylinder head 4 or may be integrally cast into the cylinder head 4.
In the embodiments shown in FIGS. 1 to 4, as mentioned above, the suction poppet valve 16 having a large diameter and a great weight directly driven to be opened and closed by the cam crests 23, 24 of the cam shaft 21, and the exhaust poppet valve 17 having a light weight indirectly driven to be opened and closed by the cam crests 22 through the rocker arm 30. Therefore, the equivalent weight of the suction system and exhaust system is uniformed, and the valve operating and closing following characteristic in the high speed rotational area is excellent.
Further, a single cam shaft 21 is used, the rocker arm 30 is formed into a shape branched in a U-shape so as to go round the wall part 34 in which the ignition plug 13 is enveloped. Therefore, a nipping angle between the suction poppet valve 16 and the exhaust poppet valve 17 is set to be small, and as a result, a combustion chamber which is high in compression
ratio, and high in combustion efficiency is constituted easily to obtain the high performance water cooling overhead valve spark ignition type single cylinder 4-cycle stroke internal combustion engine 1.
Further, one cam shaft 21 will suffice, the cam shaft 21 and the rocker arm shaft 29 are pivotally supported by the single cam shaft holder 25, and two exhaust poppet valve 17 are driven to be opened and closed by the single rocker arm 30. Therefore, the number of parts is materially reduced, the construction is simplified, and the considerably cost down and light-weighting become enabled.
Furthermore, as shown in FIG. 1, the cam shaft holder 25 is formed with the wall part 34 at the rear thereof, and the bottom part 35 somewhat inclined forwardly and upwardly is formed at the lower edge of the bottom part 34. Therefore, the corners of the wall part 34 and the bottom part 35 serve as a lubricating oil reservoir to lubricate the contact part between the cam crest 22 and the lifter 37 sufficiently.
Moreover, the lifter 37 of the position of the suction poppet valve 16 in contact with the cam crests 23, 24 and the position of the roller 33 of the rocker arm 30 of the exhaust poppet valve 17 in contact with the cam crest 22 are in a relation away by approximately 90° about the center axis of the cam shaft 21, and the opening timing of the suction poppet valve 16 and the exhaust poppet valve 17 is separated by 180° of a rotational
angle of the crank shaft 6 and by 90 of a rotational angle oF The cam shaft 21, because of which the cam crests of the cam crest 22 and the cam crest 23, 24 are at approximately same phase angle.
Further, the direction of an opening reaction of the suction poppet valve 16 and the direction of an opening reaction of the exhaust poppet valve 17 are directions different by approximately 90 from each other. Therefore, a great valve opening reaction does not exert on the cam shaft 21, thus requiring no great rigidity of the cam shaft 21> reducing the weight, and also capable of dealing with the higher speed.
Further, since the roller 33 is pivotally supported on one end of the rocker arm 30, the rotational friction force of the cam shaft 21 is reduced, and the cam crest 22 is less in friction.
Furthermore, since the cam shaft 21 is fitted in the cam shaft holder 25 through the rolling bearing 39 larger in diameter than the cam crests 22, 23, 24 of the cam shaft 21, the cam shaft 21 can be mounted from the side of the cam shaft holder 25 to considerably enhance the mounting properties.
1 ... Water cooling overhead valve spark ignition single cylinder 4-cycle stroke internal combustion engine, 2 ... crank case, 3 ... cylinder block, 4 ... cylinder head, 5 ... cylinder head cover, 6 ... crank shaft, 7 ... cylinder bore, 8 ... piston, 9 ... piston pin, 10 ... crank pin, 11 ... connecting rod, 12 ... combustion chamber, 13 ... ignition plug, 14 ... suction port, 15 ... exhaust port, 16 ... suction poppet valve, 17 ... exhaust poppet valve, 18 ... guide tube, 19 ... retainer, 2 0 ... valve spring, 21 ... cam shaft, 22 ...cam crest, 23 ... cam crest, 24 ... cam crest, 25 ... cam shaft holder, 26 ... drive sprocket, 27 ... drive sprocket, 28 ... cam chain, 29 ... rocker arm shaft, 30 ... rocker arm, 31 ... bracket, 32 ... shaft, 33 ... roller, 34 ... wall part, 35 ... bottom part, 36 ... tube part, 37 ... lifter, 38 ... ignition plug guide tube, 39 ... rolling bearing.
1.	A valve gear for an internal combustion engine (1) in which out of suction and exhaust valves (16, 17), at least one valve (17) comprises not less than two poppet valves, characterized in that a rocker arm (30) is formed into a branched shape going round an ignition plug (38) on one valve side having not less than two poppet valves (17), and other valve (16) is directly driven to be opened and closed from a cam shaft (21).
2.	A valve gear for an internal combustion engine substantially as herein described with reference to the accompanying drawings.
Dated	this the 28th day of	September,	2001
Of Refry & Sagar
934-mum-2001-cancelled pages(8-3-2006).pdf
934-mum-2001-claims(granted)-(8-3-2006).doc
934-mum-2001-claims(granted)-(8-3-2006).pdf
934-mum-2001-correspondence(3-1-2007).pdf
934-mum-2001-correspondence(ipo)-(25-7-2006).pdf
934-mum-2001-drawings(23-10-2001).pdf
934-mum-2001-form 1(28-9-2001).pdf
934-mum-2001-form 1(8-3-2006).pdf
934-mum-2001-form 18(2-9-2005).pdf
934-mum-2001-form 2(granted)-(8-3-2006).doc
934-mum-2001-form 2(granted)-(8-3-2006).pdf
934-mum-2001-form 3(15-11-2001).pdf
934-mum-2001-form 3(8-3-2006).pdf
934-mum-2001-form 5(28-9-2001).pdf
934-mum-2001-petition under rule 137(8-3-2006).pdf
934-mum-2001-power of authority(10-1-2002).pdf
934-mum-2001-power of authority(8-3-2006).pdf
934/MUM/2001
BUSINESS AT 1-1, MINAMIAOYAMA 2-CHOME, MINATO-KU, TOKYO, JAPAN
1 AKIFUMI NOMURA C/O KABUSHIKI KAISHA HONDA GIJUTSU KENKYUSHO, 4-1, CHUO 1-CHOME, WAKO-SHI, SAITAMA, JAPAN
2 YASUO SHIMURA C/O KABUSHIKI KAISHA HONDA GIJUTSU KENKYUSHO, 4-1, CHUO 1-CHOME, WAKO-SHI, SAITAMA,
3 KAZUSHISA TAKEMOT C/O KABUSHIKI KAISHA HONDA GIJUTSU KENKYUSHO, 4-1, CHUO 1-CHOME, WAKO-SHI, SAITAMA, JAPAN
4 AKIRA TOKITO C/O KABUSHIKI KAISHA HONDA GIJUTSU KENKYUSHO, 4-1, CHUO 1-CHOME, WAKO-SHI, SAITAMA, JAPAN
F 01 L 1/00
1 2000-314086 2000-10-13 Japan