Title of Invention

CAM CHAIN LIFTER SYSTEM FOR INTERNAL COMBUSTION ENGINES

Abstract [Problem]To provide a cam chain lifter system for internal combustion engines in which the cam chain lifter system can be disposed at the optimum position without pusizing the internal combustion engine. [Means for Resolution] In an internal combustion engine comprising a cam chain lifter with an oil lock mechanism, a cam chain lifter 31 for internal combustion engine wherein a cam chain lifter with oil lock mechanism is disposed in the cam chain chamber 9 with a push rod 32 slidably held in a guide cylilnder 34 so as to project upward therefrom, and the upper portion of the guide cylinder 34 from which the push rod 32 projects is opened upward to form an oil pit 35 in communication with the hydraulic chamber 46 in the guide cylinder via the interior of the push rod 32.
Full Text FORM 2
THE PATENTS ACT 1970
[39 OF 1970]
COMPLETE SPECIFICATION
[See Section 10]
"CAM CHAIN LIFTER SYSTEM FOR INTERNAL COMBUSTION ENGINES"
HONDA GIKEN KOGYO KABUSHIKI KAISHA, a corporation of Japan, having a place of business at 1-1, Minamiaoyama 2-chome, Minato-ku, Tokyo, Japan,
The following specification particularly describes the nature of the invention and the manner in which it is to be performed:-

The present invention relates to cam chain lifter system for internal combusion engines.
[0002] [Prior Art]
The cam chain lifter with an oil lock mechanism must always keep a hydraulic chamber within a guide cylinder for slidably holding a push rod filled with oil to enable oil lock so that the push rod applied with a pressure from a cam chain will not be moved excessively backward. [0003]
There are examples in which an oil pit is specially formed and the cam chain lifer is soaked into this oil pit (See Japanese Patent Laid-open No.280490/1999, Japanese Patent Publication No.14224/1988/ and Japanese Utility Model Laid-Open No.126138/1986). [0004]
[Problems that the Invention is to Solve] However, since the oil pifmust have dimensions as large as the cam chain lifter can be soaked, the position where such a large space can be retained is limited, and thus the freedom of layout of the cam chain lifter is low. [00.05] There is a case where a space cannot be retained at the


optimum position for the cam chain lifter, and in such a case, the oil pit is formed by swelling out the crankcase or the cylinder block as stated in the patent publications, which increases the size of the body of the internal combustion engine.
[0006]
With these circumstances in view, it is an object of the present invention to provide a cam chain lifter system for internal combustion engines in which the cam chain lifter system can be arranged at the optimum position without upsizing the internal combustion engine.
[0007]
[Means for Solving the Problems and Advantages]
In order to achieve the above described object, the invention according to Claim 1 is, in an internal combustion engine comprising a cam chain lifter with an oil lock mechanism, a cam chain lifter for internal combustion engine wherein a cam chain lifter with oil lock mechanism is disposed in the cam chain chamber with a push rod slidably held in a guide cylinder so as to project upward therefrom, and the upper portion of the guide cylinder from which the push rod projects is opened upward to form an oil pit in communication with the hydraulic chamber in the guide cylinder via the interior of the push rod.
[0008]


Since the cam chain lifter positioned in the cam chain chamber forms an oil pit opening upward at the upper portion of the guide cylinder from which the push rod projects, oil spattered in the cam chain chamber is collected in the oil pit and thus the interior of the guide cylinder in communication therewith is always filled with oil so as to enable oil lock.
[0009]
Since the oil pit for supplying oil to the hydraulic chamber in the guide cylinder is formed on the upper portion of the guide cylinder from which the push rod projects, a compact structure in which the cam chain lifter itself includes an oil pit thereon is realized, whereby the freedom of layout of the cam chain lifter is increased, and the cam chain lifter can be disposed at the optimum position without upsizing the internal combustion engine.
[0010]
The invention according to Claim 2 is a cam chain lifter system for internal combustion engine according to Claim 1, characterized in that an oil pit is formed by forming a groove on the upper portion of the guide cylinder being swelled out in the radial direction so as to be opened upward and toward the outside, and closing the opening of the groove facing toward the outside with an oil pit plate, and in that the outside of the oil pit plate faces toward the starter driven gear to serve as a thrust receiver.


[0011]
Sine the oil pit plate constitutes the oil pit and faces toward the starter driven gear so as to serve as a thrust receiver, it serves as an oil pit and as a thrust receiver, thereby reducing the number of components and thus lowering the cost.
[Brief Description of the Drawings]
[Fig. 1]
Fig. 1 is a side view showing the cam chain chamber on the left side of the internal combustion engine according to the present invention.
[Fig. 2] .
Fig. 2 is a cross sectional view of the cam chain chamber.
[Fig. 3]
Fig. 3 is a side view of the principal portion of the crankcase.
[Fig. 4]
Fig. 4 is a cross sectional view of the cam chain lifter.


[0012]
[Mode for Carrying Out the Invention]
Referring now to Fig. 1 through Fig. 4, an embodiment of the present invention will be described.
The body of a single cylinder OHC 4-stroke cycle internal combustion engine 1 mounted on a motorcycle (not shown) is constructed in such a manner that, as shown in Fig. 1, a cylinder block 3 having a substantially horizontally oriented cylinder bore is projected forwardly (left side in Fig. 1) of the left and right halves of crankcases 2 , 2, a cylinder head 4 is covered on the front end of the cylinder block 3, and the cylinder head 4, the cylinder block 3, and the left and right crankcases 2, 2 are integrally joined with bolts 5 screwed through the cylinder head 4 and the cylinder block 3 into the left and right crankcases 2, 2 from the front of the vehicle body.
[0013]
A crankshaft 6 oriented in the direction of the width of the vehicle is rotatably supported by the left and right crankcases 2, 2 via a ball bearing 7.


As shown in Fig. 2, the ball bearing 7 is fitted into a circular opening formed on a sidewall 2a of the left crankcase 2, and the crankshaft 6 is passed through the inner lace of the ball bearing 7 and projected toward the left.
[0014]
The left side of the sidewall 2a of the left crankcase 2 and the left sides of the cylinder block 3 and the cylinder head 4 are covered by a chain cover 8, so that a common cam chain chamber 9 is formed therein.
[0015]
An AC generator 10 is mounted at the left end of the crankshaft 6 projected into the cam chain chamber 9, and a drive sprocket 15 is fitted on the crankshaft 6 between the AC generator 10 and the sidewall 2a of the left crankcase 2.
[0016]
A starter driven gear 12 is rotatably supported on the crankshaft 6 on the left side of the drive sprocket 15 near the AC generator 10 via a one-way clutch 11, and the starter driven gear 12 engages an intermediate gear 13 so that the starter driven gear 12 transmits a power unidirectionally from the starter motor, not shown, to the crankshaft 6.
[0017]
As shown in Fig. 1, a driven sprocket 16 fitted on a cam shaft 14 is provided in the cam chain chamber 9 of the cylinder head 4, and an endless cam chain 17 is routed between the driven


sprocket 16 and the drive sprocket 15.
[0018]
A cylindrical boss 21 is provided on the sidewall 2a of the left crankcase 2 above and obliquely behind the crankshaft 6 so as to project toward the left, and a tensioner arm 23 of the cam chain lifter system 2 0 is pivotally supported by a shaft 22 to be screwed into the boss 21.
[0019]
The tensioner arm 23 extends forward and backward from the shaft 22, and the front end of the arm extending forward rotatably supports a tension sprocket 24, and the tension sprocket 24 engages the cam chain 17 and presses the same from above (See Fig. 1).
[0020]
The rear end of the arm extending obliquely toward the lower rear of the tension arm 23 abuts against a rod head 33 at the upper end of the push rod 32 of the cam chain lifter 31 with an oil lock mechanism.
[0021]
A cam chain lifter 31 is integrally formed in such a manner that a guide cylinder 34, which is inclined slightly toward the rear with respect to the vertical line, passes obliquely through the bottom wall of the cam chain chamber 9 of the left crankcase 2 as shown in Fig. 3, and a push rod 32 is slidably inserted into the circular boar of the guide


cylinder 34.
[0022]
The guide cylinder 34 projects to the outside at its lower end, and an opening formed at the lower end thereof is closed by a sealing bolt 41 screwed therein (See Fig. 1, Fig. 4).
On the other hand, the upper portion of the guide cylinder 34, being located within the cam chain chamber 9, is swelled out in the radial direction in the square shape, and formed with an oil pit 3 5 therein.
[0023]
As shown in Fig. 3, the upper end surface (dot-dashed line Lc) of the opening of the guide cylinder 34 which is swelled into the square shape is substantially horizontal, the left wall of the oil pit 35 is vertically notched and thus opened to form a groove 36, and the notched surface serves as a mating surface 37 against which an oil pit plate 38 is abutted to close the left opening of the groove 36 so that the oil pit 35 having a square opening only on the top thereof is formed.
[0024]
A boss 39 for mounting the oil pit plate 38 is integrally formed at the front of the guide cylinder 34 along the upper portion thereof.
As shown in Fig. 2, the oil pit plate 38 forms an oil pit 3 5 in such a manner that a distal end 38b bent into a crank shape from a mounting proximal end 38a to be secured by screwing

a bolt 40 through the boss 39 abuts against the mating surface 37 of the groove 36 and closes the left opening so that the oil pit 35 is formed.
[0025]
The distal end 38b that closes the left opening of the groove 36 of the oil pit plate 38 is formed with a projection 3 8c swelling partially toward the left.
The oil pit plate 3 8 is located below and obliquely behind the crankshaft 6 and within the outer periphery of the starter driven gear 12 as shown in Fig. 1, and the distal end 3 8b faces toward the right side surface of the starter driven gear 12 with the projection 38c being in contact therewith to serve as a thrust receiver for preventing axial displacement of the starter driven gear 12 as shown in Fig. 2.
[0026]
In the cam chain lifter 31, as shown in Fig. 4, since the push rod 32 is slidably inserted into the circular bore in the guide cylinder 34, and the circular bore opens toward the oil pit 35, the push rod 31 seems to project upward from the bottom of the oil pit 35.
[0027] •
The push rod 32, being cylindrical in shape, is formed with a plurality of communicating holes 32a along the appropriate length of the central portion thereof and fitted with the rod head 33 on the opening at the upper end, and a


vent hole 3 2b is formed in the vicinity of the rod head 33.
[0028]
A ball 43 is loosely fitted between the ball seat 42 in the shape of a cap and a valve cap 44 at the opening at the lower end of the push rod 32.
Openings 42a, 44a, each having a size through which the ball 43 cannot pass through, are formed on the ball seat 42 and on the bottom wall of the valve cap 44, so that a check valve in which the ball 43 opens and closes the opening 42a of the ball seat 42 is constructed.
[0029]
A spring 45 is interposed between the sealing bolt 41 to be screwed into the lower end of the guide cylinder 34 and the lower end of the push rod 32 for urging the push rod 32 upward.
A space below the ball seat 42 in which the spring 45 is interposed forms a hydraulic chamber 46.
[0030]
Since the push rod 32 is adapted in such a manner that it is inserted to a substantially half of it into the guide cylinder 34 and any one of the plurality of communicating holes 32a at the center thereof is aligned with the oil pit 35, the oil pit 35 comes into communication with the interior of the push rod 32 via the communicating hole 32a, and the interior of the push rod 32 is in communication with the hydraulic


chamber 46 via the normally opened opening 42a of the ball seat 42 and the opening 44a of the valve cap 44.
[0031]
The interior of the guide cylinder 34 is filled with oil, and the hydraulic chamber 46 is filled with oil to the lower half of the interior of the inserted push rod 32 and to the oil pit 35 as a matter of course, and thus oil is filled to the upper end surface of the guide cylinder 34 shown by the dash-dotted line Lc in Fig. 4.
[0032]
In the cam chain lifter system 2 0 having such a structure as described above, oil is stored at the lower portion of the crankcase 2, while in the cam chain chamber 9, oil is accumulated to the level shown by the dash-dotted line Lo in Fig. 1, so that the guide cylinder 34 of the cam chain lifer 31 is partially soaked into oil.
[0033]
Oil spattered by the revolution of the starter driven gear 12 or the rotation of cam chain 17 caused by driving of internal combustion engine 1 is collected into the oil pit 35 opening upward at the upper end of the guide cylinder 34 and thus oil is always refilled.
[0034]
With the cam chain lifter system 20, the push rod 32 is urged upward by the spring 45 of the cam chain lifter 31 and


the tensioner arm 23 is pivoted about the shaft 22, so that the tensioner sprocket 24 presses against the cam chain 17 to maintain an appropriate tension on the cam chain 17.
[0035]
Stretch of the cam chain 17 may be accommodated by advancing the push rod 32 forward by an urging force of the spring 45.
[0036]
In the case where the cam chain 17 is excessively tensed, and the push rod 32 moves rearward against the urging force of the spring 45 by the pressure applied from the cam chain 17, the ball seat 42 moves backward with the push rod 32 and thus the opening 42a which is normally in the communicated state is closed by the ball 43, thereby shutting oil in the hydraulic chamber 46 and preventing excessive backward movement of the push rod 32.
[0037]
In order to ensure this oil lock mechanism, the guide cylinder 34 has to be filled with oil all the time.
In the case of the cam chain lifter system 20 of the present invention, oil spattered in the cam chain chamber 9 is collected in the oil pit 35 opening upward at the upper end of the guide cylinder 34, and thus oil is always refilled.
[0038]
Since the oil pit 35 for supplying oil to the hydraulic


chamber 4 6 of the cam chain lifter 31 is formed on the upper portion of the guide cylinder 34 from which the push rod 32 projects, a compact structure in which the cam chain lifter 31 itself includes an oil pit thereon is realized, whereby the freedom of layout of the cam chain lifter.31 is increased, and the cam chain lifter 31 can be disposed at the optimum position without upsizing the internal combustion engine.
[0039]
Since the oil pit plate 38 constitutes the oil pit 35 and faces toward the starter driven gear 12 to serve also as a thrust receiver, it serves as an oil pit and as a thrust receiver, thereby decreasing the number of components and thus lowering the cost.


[Description of the Reference Numerals and Signs] 1...internal combustion engine, 2...crankcase, 3...cylinder block, 4...cylinder head, 5...bolt, 6...crankshaft, 7...ball bearing, 8...chain cover, 9...cam chain chamber, 10...AC generator, 11...one-way clutch, 12...starter driven gear, 13 ... intermediate gear, 14...cam shaft, 15...drive sprocket, 16..driven sprocket, 17...cam chain, 20...cam chain lifter system, 21...boss, 22...shaft, 23...tensioner arm, 24...tension sprocket, 31...cam chain lifter, 32...push rod, 33...rod head, 34...guide cylinder, 35...oil pit, 36...groove, 37...mating surface, 38...oil pit plate, 39...boss, 40...bolt, 41...sealing bolt, 42...ball seat, 43...ball, 44...valve cap, 45...spring, 46...hydraulic chamber


WE CLAIM:
1. In an internal combustion engine comprising a cam chain lifter (31)
with an oil lock mechanism,
a cam chain lifter (31) for internal combustion engine wherein a cam chain lifter (31) with oil lock mechanism is disposed in the cam chain chamber (9) with a push rod (32) slidably held in a guide cylinder (34) so as to project upward therefrom,
and the upper portion of the guide cylinder (34) from which the push rod (32) projects is opened upward to form an oil pit (35) in communication with the hydraulic chamber (46) in the guide cylinder (34) via the interior of the push rod (32).
2. A cam chain lifter (31) system for internal combustion engine as
claimed in claim 1, wherein an oil pit (35) is formed by forming a groove (36)
on the upper portion of the guide cylinder (34) being swelled out in the
radial direction so as to be opened upward and toward the outside, and
closing the opening of the groove facing toward the outside with an oil pit
plate (38), and
the outside of the oil pit plate (38) faces toward the starter driven gear to serve as a thrust receiver.
3 A cam chain lifter (31) system for internal combustion engine
substantially as herein described with reference to the accompanying drawings.
Dated this 21st March, 2002.
[VINEET ROHILLA]
OF REMFRY & SAGAR
ATTORNEY FOR THE APPLICANT[S]

Documents:

270-mum-2002-cancelled pages(11-12-2007).pdf

270-mum-2002-claims(granted)-(11-12-2007).doc

270-mum-2002-claims(granted)-(11-12-2007).pdf

270-mum-2002-correspondence(26-12-2007).pdf

270-mum-2002-correspondence(ipo)-(24-12-2007).pdf

270-mum-2002-drawing(11-12-2007).pdf

270-mum-2002-form 1(11-12-2007).pdf

270-mum-2002-form 1(21-03-2002).pdf

270-mum-2002-form 13(11-12-2007).pdf

270-mum-2002-form 18(10-02-2006).pdf

270-mum-2002-form 2(granted)-(11-12-2007).doc

270-mum-2002-form 2(granted)-(11-12-2007).pdf

270-mum-2002-form 3(11-12-2007).pdf

270-mum-2002-form 3(12-04-2004).pdf

270-mum-2002-form 3(21-03-2002).pdf

270-mum-2002-form 5(11-12-2007).pdf

270-mum-2002-form 5(21-03-2002).pdf

270-mum-2002-petition under rule 137(11-12-2007).pdf

270-mum-2002-petition under rule 138(11-12-2007).pdf

270-mum-2002-power of authority(11-12-2007).pdf

270-mum-2002-power of authority(28-05-2002).pdf

abstract1.jpg


Patent Number 213193
Indian Patent Application Number 270/MUM/2002
PG Journal Number 04/2008
Publication Date 25-Jan-2008
Grant Date 24-Dec-2007
Date of Filing 21-Mar-2002
Name of Patentee HONDA GIKEN KOGYO KABUSHIKI KAISHA
Applicant Address 1-1, MINAMIAOYAMA 2-CHOME, MINATO-KU, TOKYO, JAPAN
Inventors:
# Inventor's Name Inventor's Address
1 TOSHIHARU AKUTSU C/O KABUSHIKI KAISHA HONDA GIJUTSU KENKYUSHO, 4-1, CHUO 1-CHOME, WAKO-SHI, SAITAMA, JAPAN
2 YOSHINOBU SAWAMURA c/o Kabushiki Kaisha Honda Gijutsu Kenkyusho, of 4-1, Chuo 1-Chome, Wako-shi, Saitama,
3 YUICHI WASADA c/o Kabushiki Kaisha Honda Gijutsu Kenkyusho, of 4-1, Chuo 1-Chome, Wako-shi, Saitama,
4 HIDEO KOBAYASHI c/o Kabushiki Kaisha Honda Gijutsu Kenkyusho, of 4-1, Chuo 1-Chome, Wako-shi, Saitama,
PCT International Classification Number F02B 67/06
PCT International Application Number N/A
PCT International Filing date
PCT Conventions:
# PCT Application Number Date of Convention Priority Country
1 2001-116887 2001-04-16 Japan