WO2016072385A1 - Internal combustion engine - Google Patents
Internal combustion engine Download PDFInfo
- Publication number
- WO2016072385A1 WO2016072385A1 PCT/JP2015/080918 JP2015080918W WO2016072385A1 WO 2016072385 A1 WO2016072385 A1 WO 2016072385A1 JP 2015080918 W JP2015080918 W JP 2015080918W WO 2016072385 A1 WO2016072385 A1 WO 2016072385A1
- Authority
- WO
- WIPO (PCT)
- Prior art keywords
- cylinder
- bolt mounting
- mounting boss
- cylinder head
- combustion engine
- Prior art date
Links
Images
Classifications
-
- F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
- F02—COMBUSTION ENGINES; HOT-GAS OR COMBUSTION-PRODUCT ENGINE PLANTS
- F02F—CYLINDERS, PISTONS OR CASINGS, FOR COMBUSTION ENGINES; ARRANGEMENTS OF SEALINGS IN COMBUSTION ENGINES
- F02F1/00—Cylinders; Cylinder heads
-
- F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
- F02—COMBUSTION ENGINES; HOT-GAS OR COMBUSTION-PRODUCT ENGINE PLANTS
- F02F—CYLINDERS, PISTONS OR CASINGS, FOR COMBUSTION ENGINES; ARRANGEMENTS OF SEALINGS IN COMBUSTION ENGINES
- F02F1/00—Cylinders; Cylinder heads
- F02F1/24—Cylinder heads
- F02F1/26—Cylinder heads having cooling means
- F02F1/28—Cylinder heads having cooling means for air cooling
- F02F1/30—Finned cylinder heads
- F02F1/32—Finned cylinder heads the cylinder heads being of overhead valve type
-
- F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
- F02—COMBUSTION ENGINES; HOT-GAS OR COMBUSTION-PRODUCT ENGINE PLANTS
- F02F—CYLINDERS, PISTONS OR CASINGS, FOR COMBUSTION ENGINES; ARRANGEMENTS OF SEALINGS IN COMBUSTION ENGINES
- F02F1/00—Cylinders; Cylinder heads
- F02F1/24—Cylinder heads
- F02F1/42—Shape or arrangement of intake or exhaust channels in cylinder heads
Definitions
- the present invention relates to an internal combustion engine in which a cylinder head is miniaturized.
- a mounting boss of the stud bolt disposed around the cylinder bore is a valve formed on the cylinder head It is arranged in the mechanism storage room.
- Patent Document 1 a part of mounting bosses of a plurality of stud bolts is disposed outside a valve mechanism housing chamber of the cylinder head.
- Patent Document 1 discloses an air-cooled engine (internal combustion engine) in which a cylinder head having a valve operating mechanism accommodation chamber for accommodating a valve operating mechanism is fixed by a plurality of stud bolts in a cylinder integrated with a crankcase. It is done.
- the internal combustion engine disclosed in Patent Document 1 is an OHV air-cooled internal combustion engine having a push rod, which has a small number of parts used for a valve train, and is a part of a plurality of mounting bosses of a stud bolt.
- the cylinder head can be easily downsized by arranging the valve mechanism outside the valve operating mechanism accommodating chamber to make the valve operating mechanism accommodating chamber smaller, thereby achieving downsizing of the internal combustion engine.
- valve mechanism storage chamber In an OHC type internal combustion engine having a camshaft, the number of parts used in the valve operating mechanism is large, and even if a part of the plurality of mounting bosses of the stud bolt is arranged outside the valve operating mechanism accommodating chamber It is not easy to miniaturize the valve mechanism storage chamber.
- the stud bolts are evenly distributed in the circumferential direction of the cylinder bore close to the circumference of the cylinder bore to receive the pressure in the cylinder bore, a portion of the plurality of mounting bosses of the stud bolt is moved
- the valve operating mechanism, the mounting boss and the arrangement of the wall of the cylinder head interfere with each other, so the valve operating mechanism accommodating chamber is brought close to the periphery of the cylinder bore. It is not easy to put it outside.
- the cylinder head is miniaturized, it is necessary to consider securing of a tool space for the stud bolt and the like.
- the present invention is to solve the above-mentioned problems, and an object of the present invention is to provide an internal combustion engine which has good maintainability, and which is reduced in size and weight.
- an internal combustion engine has an outer peripheral wall having a crankcase, a cylinder block having a cylinder bore inside, and an outer peripheral wall forming a valve operating mechanism accommodating chamber for accommodating a valve operating mechanism. And a cylinder head having a plurality of cooling fins formed thereon, and the cylinder block and the cylinder head are sequentially stacked on the crankcase and integrally fastened by a plurality of stud bolts and fastening members attached to the stud bolts.
- a plurality of the stud bolts are arranged to circumferentially surround the cylinder bore in a cylinder center axis direction seen through a center line of the cylinder bore, and a plurality of the stud bolts pass through the cylinder head, respectively.
- a bolt mounting boss is formed, and the plurality of bolt mounting bosses are the cylinder head
- An internal combustion engine comprising: an inner bolt mounting boss portion disposed inside the valve operating mechanism housing chamber; and an outer bolt mounting boss portion disposed outside the valve operating mechanism housing chamber of the cylinder head.
- the outer peripheral wall has a recess formed so that a portion of the outer peripheral wall is recessed inward so as to avoid the bearing surface of the fastening member of the outer bolt mounting boss portion as viewed in the cylinder center axial direction. It is characterized by
- the bearing surface of the outer bolt mounting boss can be disposed close to the periphery of the cylinder bore, and the plurality of bolt mounting bosses can be disposed while the stud bolt is disposed approximately equally around the cylinder bore.
- the valve operating mechanism accommodating chamber can be made smaller.
- the cylinder block including the outer bolt mounting boss can be made smaller.
- tool spaces for stud bolts and fastening members can be formed on the outer peripheral wall to improve maintainability.
- the valve operating mechanism chamber and the outer bolt mounting boss portion small, the cylinder head can be made smaller and lighter, and an internal combustion engine with good maintainability, smaller and lighter is provided. can do.
- the bearing surface of the outer attachment boss portion is located closer to the cylinder block than at least a part of the plurality of cooling fins in a side view, and the plurality of cooling fins are The region overlapping with the seat surface may be avoided when viewed in the cylinder center axis direction.
- the bearing surface of the outer bolt mounting boss outside the valve mechanism accommodation chamber is positioned closer to the cylinder block than a part of the cooling fin, so the cylinder center axis of the outer bolt mounting boss is The height of the direction can be reduced, and the cylinder head can be made smaller and lighter. Furthermore, since the cooling fins are formed avoiding the tool space for the stud bolts, interference between the tool and the cooling fins can be avoided. Therefore, it is possible to miniaturize the cylinder head while maintaining maintainability, and it is possible to provide an internal combustion engine which is excellent in maintainability and which is reduced in size and weight.
- the internal combustion engine is an OHC type internal combustion engine in which a camshaft is disposed in the valve operating mechanism accommodation chamber, and a transmission mechanism for transmitting a driving force to the camshaft is the cylinder central axis view.
- the outer bolt mounting boss may be disposed on the opposite side of the cylinder bore.
- the outer bolt mounting boss portion can be formed without considering the space required for the disposition and maintenance of the transmission mechanism, and the working space around the stud bolt It is possible to secure and further maintain maintainability.
- the cylinder head is provided with an intake port and an exhaust port, and the bearing surface of the outer bolt boss portion is closer to the cylinder block than a ceiling wall of the intake port and the exhaust port in a side view. It may be located in
- the outer bolt mounting boss can be further reduced, and the cylinder head can be further reduced in size and weight.
- the cooling fin may be formed on the outer wall surface of the intake port and the exhaust port.
- the outer attachment wall surface of the intake port and the exhaust port exposed to the outside is cooled by positioning the seat surface of the outer mounting boss portion closer to the cylinder block than the ceiling surface of the intake port and the exhaust port. Fins will be formed. Therefore, the cooling performance of the entire cylinder head can be improved while achieving downsizing and weight reduction of the cylinder head.
- the valve mechanism may include one intake valve and one exhaust valve.
- the valve train can be miniaturized, and the cylinder head can be further miniaturized and reduced in weight.
- the outer bolt mounting boss portion is disposed outside the valve operating mechanism accommodation chamber, the degree of freedom in the arrangement of the valve operating mechanism is improved, and two valves can be easily arranged symmetrically with respect to the cylinder center axis. The fuel combustion efficiency can be improved.
- a head cover that covers the valve operating mechanism accommodation chamber is attached to the cylinder head, and an outer peripheral wall of the head cover is a part of the outer peripheral wall of the head cover in the axial direction of the cylinder center.
- a recess may be formed inward so as to avoid the bearing surface of the bolt mounting boss.
- the tool space around the stud bolt arranged in the outer bolt mounting boss can be formed also in the head cover, and the maintenance can be further improved.
- At least one of the seating surfaces of the fastening members of the inner bolt mounting boss may be provided with a cutout for discharging lubricating oil.
- the cylinder head is provided with a spark plug hole for inserting and supporting a spark plug, and the spark plug hole is positioned between a pair of outer bolt mounting bosses among the outer bolt mounting bosses. Also good.
- the spark plug hole can be formed integrally with the outer bolt mounting boss portion between the outer bolt mounting boss portions, and the cylinder head can be made smaller and lighter, and the smaller outer side can be formed. Since the spark plug hole is formed integrally with the bolt mounting boss, the heat capacity around the spark plug hole can be reduced, and the cooling effect of the spark plug can be improved.
- the bolt mounting boss portion of the stud bolt is disposed outside the valve operating mechanism accommodating chamber of the cylinder head to miniaturize the valve operating mechanism accommodating chamber. Further, the outer bolt mounting boss can be disposed close to the cylinder bore and can be formed small, and the cylinder head can be made smaller and lighter. Furthermore, since a part of the outer peripheral wall of the cylinder head is formed avoiding the stud bolt and the tool space for the fastening member, the tool and the outer peripheral can be obtained by making the outer bolt mounting boss portion adjacent to the outer peripheral wall of the cylinder head. Interference with the wall can be avoided. Therefore, it is possible to miniaturize the cylinder head while maintaining maintainability, and it is possible to provide an internal combustion engine which is excellent in maintainability and which is reduced in size and weight.
- FIG. 1 is a left side view of a partial cross section of an internal combustion engine according to an embodiment of the present invention.
- FIG. 1 is a partially enlarged right side view of an internal combustion engine according to an embodiment of the present invention.
- FIG. 3 is a top view according to arrow III of the internal combustion engine shown in FIG. 2;
- FIG. 4 is a top view of the internal combustion engine shown in FIG. 3 with the head cover removed.
- FIG. 5 is a cross-sectional view taken along line VV of FIG. 4; It is the top view which abbreviate
- the internal combustion engine E according to an embodiment of the present invention is an SOHC type two-valve single-cylinder four-stroke internal combustion engine mounted on a motorcycle (not shown) as a vehicle, and the crankshaft 11 is extended from the vehicle body (not shown). It is mounted on the vehicle with a directional orientation.
- the front, rear, left, right, and up and down directions follow the direction of the motorcycle.
- arrow FR indicates the front
- RE indicates the rear
- LT indicates the left
- RT Indicates the right side, respectively.
- FIG. 1 is a left side view of a partial cross section of an internal combustion engine E according to an embodiment of the present invention
- FIG. 2 is an enlarged right side of an internal combustion engine E according to an embodiment of the present invention
- FIG. 3 is a top view of the internal combustion engine E shown in FIG.
- the internal combustion engine E includes a crankcase 1 rotatably supporting a crankshaft 11, a cylinder block 2 having one cylinder bore 21, and a valve housing a valve mechanism 80.
- a cylinder head 3 having a mechanism accommodation chamber 32 and a head cover 6 covering a valve operating mechanism accommodation chamber 32 of the cylinder head 3 are provided.
- the cylinder center axis C1 passing through the center axis of the cylinder bore 21 is obliquely inclined forward to the upper front of the crankcase 1 so that the cylinder block 2 is overlapped, and the cylinder (not shown) is interposed on the cylinder block 2
- the heads 3 are overlapped, and these are fastened together by a stud bolt 70.
- a head cover 6 is superimposed on the cylinder head 3, and the head cover 6 is attached to the cylinder head 3 by bolts 75.
- crank shaft 11 is rotatably supported at the center of a front half of the crankcase 1, and a main shaft 12 and a counter shaft 13 are rotatably supported at the rear of the crank shaft 11.
- a gear type transmission mechanism 14 is disposed between the main shaft 12 and the counter shaft 13.
- an oil pump 17 is disposed at the lower front of the crankshaft 11.
- a piston 22 is slidably fitted in a cylinder bore 21 of the cylinder block 2 in a reciprocating manner.
- the piston 22 is connected to the crankshaft 11 by connecting the connecting rod 15 between the piston pin 22 a of the piston 22 and the crank pin 11 a of the crankshaft 11.
- a plurality of cooling fins 23 are formed on the outer wall surface 2 a of the cylinder block 2 so as to extend outward.
- a combustion chamber 33 is formed between the top surface 22 b of the piston 22 and the combustion chamber upper wall portion 33 a provided at the lower portion of the cylinder head 3.
- One intake valve port 33b and one exhaust valve port 33c are opened in the combustion chamber upper wall portion 33a so as to face the combustion chamber 33 at mutually opposite positions with respect to the cylinder center axis C1.
- An intake port 40 extends from the intake valve port 33b, and an exhaust port 42 extends from the exhaust valve port 33c in a direction away from each other while curving.
- An intake valve 81 is attached to the intake valve port 33b of the cylinder head 3, and an exhaust valve 82 is attached to the exhaust valve port 33c.
- the intake valve 81 and the exhaust valve 82 are disposed obliquely to the combustion chamber 33 so as to be substantially symmetrical with respect to the cylinder center axis C1.
- FIG. 4 is a top view of the internal combustion engine E shown in FIG. 3 with the head cover 6 removed
- FIG. 5 is a cross-sectional view taken along the line VV in FIG.
- the cylinder bores 21 of the cylinder block 2 are indicated by meshing.
- the intake valve 81 and the exhaust valve 82 are each biased in the closing direction by the valve spring 83, and the valve mechanism 80 disposed in the cylinder head 3 as shown in FIG.
- the opening and closing of the crankshaft 11 is performed at a predetermined timing.
- the cylinder head 3 has an outer peripheral wall 30 having a substantially rectangular shape in a direction of the cylinder center axis C1, and also referring to FIG. 1, a space surrounded by the outer peripheral wall 30 of the cylinder head 3.
- the valve operating mechanism accommodating chamber 32 in which the valve operating mechanism 80 is accommodated is formed in the upper part of the valve.
- valve operating mechanism 80 is an SOHC type valve operating mechanism 80 in which a single camshaft 84 is supported by being directed in the left-right direction on the upper portion of the cylinder head 3.
- a rocker arm shaft 85, an intake rocker arm 86 and an exhaust rocker arm 87 are provided.
- a left bearing portion 34L and a right bearing portion 34R are formed so as to protrude upward facing the upper portion of the combustion chamber upper wall portion 33a of the combustion chamber 33 of the cylinder head 3 in the left-right direction.
- a camshaft 84 is rotatably mounted on the left and right bearing portions 34L, 34R via bearings (not shown).
- a single rocker arm shaft 85 is mounted in parallel with the camshaft 84 on the upper portions 34La, 34Ra of the left and right bearing portions 34L, 34R.
- An intake rocker arm 86 and an exhaust rocker arm 87 are adjacently supported by the rocker arm shaft 85 so as to be freely pivotable.
- a driven cam chain sprocket 92 of a chain sprocket mechanism 90 which is a transmission mechanism, is fitted to a left end portion 84L of a camshaft 84 which penetrates a bearing (not shown) provided on the left bearing portion 34L of the cylinder head 3.
- a cam chain chamber 2 c communicating with the cam chain chamber 3 c of the cylinder head 3 is formed penetrating vertically.
- a cam chain 93 is bridged between the driven cam chain sprocket 92 and a drive cam chain sprocket (not shown) fitted to the crankshaft 11 through the cam chain chamber 2 c of the cylinder block 2.
- the rotational driving force of the crankshaft 11 which is rotationally driven by the movement of the piston 22 in the sliding direction, is transmitted to the camshaft 84 at a half rotational speed via the chain sprocket mechanism 90.
- the intake valve 81 and the exhaust valve 82 are opened and closed in synchronization with the rotation of the crankshaft 11 in conjunction with the rotation of the camshaft 84.
- the cylinder head 3 is crankcased by four stud bolts 70 arranged so as to circumferentially substantially equally surround the circumference of the cylinder bore 21 when viewed in the direction of the cylinder center axis C1. 1 and the cylinder block 2 are fastened together.
- four bolt mounting bosses 50 for mounting the stud bolts 70 are formed in the cylinder head 3 so as to surround the cylinder bore 21 as viewed in the direction of the cylinder center axis C1.
- a bolt insertion hole 50b through which the stud bolt 70 passes is formed along the direction of the cylinder center axis C1.
- the upper opening surface of the bolt insertion hole 50b of the bolt mounting boss 50 is formed as a circular seating surface 50a to which a nut 71, which is a fastening member for fixing the stud bolt 70, is fixed via the washer 72.
- the four bolt insertion holes 50b formed in this manner are disposed at positions substantially equally surrounding the periphery of the cylinder bore 21 in the circumferential direction as viewed in the direction of the cylinder center axis C1.
- the bolt mounting bosses 50 are formed in a substantially cylindrical shape so as to surround the bolt insertion holes 50 b, and are provided with two inner bolt mounting bosses 51 disposed inside the valve mechanism accommodation chamber 32. And two outer bolt mounting bosses 55 disposed outside the valve operating mechanism housing 32.
- the inner bolt mounting boss portion 51 is located on the left diagonal rear of the cylinder bore 21 and is integrally formed with the left bearing portion 34L when viewed in the cylinder center axis C1 direction, and the left of the cylinder bore 21
- a second inner bolt mounting boss 53 is formed obliquely with the front and integrally formed with the left bearing 34L.
- the bearing surface 51 a of the inner bolt mounting boss 51 is located between the camshaft 84 and the head cover side mating surface 3 e of the cylinder head 3 in a cross sectional side view.
- a notch 52c is cut out toward the upper end of the intake valve 81 located radially outward from the bolt insertion hole 52b. Is formed.
- the bolt insertion hole 52b formed in the first inner bolt mounting boss portion 52 is communicated with an oil supply passage (not shown) provided in the crankcase 1 and doubles as a part of the oil supply passage.
- the oil supplied from the oil pump 17 is discharged from the notch 52c toward the valve mechanism 80, so that lubricating oil can be reliably supplied to the valve mechanism 80.
- the region from the approximate center of the front half to the end of the rear half in the front-rear direction of the cylinder block side end 30Rb of the right side wall 30R The right bulging portion 31 is formed by bulging.
- An outer bolt mounting boss 55 is integrally formed on the right bulging portion 31.
- the outer bolt mounting boss 55 is positioned diagonally to the right rear of the cylinder bore 21 and integrally formed at the right rear end of the right bulging portion 31 in the direction of the cylinder center axis C1. It comprises an outer bolt mounting boss portion 56 and a second outer bolt mounting boss portion 57 positioned diagonally forward to the right of the cylinder bore 21 and integrally formed at the right front end of the right bulging portion 31.
- the bearing surface 55 a of the outer bolt mounting boss 55 is more cylindrical than the ceiling wall 41 b of the wall 41 of the intake port 40 and the ceiling 43 b of the wall 43 of the exhaust port 42 in side view. It is located on the block 2 side, substantially in the center of the lower half of the cylinder head 3 in the direction of the cylinder center axis C1 (that is, approximately one-fourth the height of the cylinder head 3).
- the bearing surface 52a of the first inner bolt mounting boss 52 is located on the left rear of the cylinder bore 21 and the bearing surface 53a of the second inner bolt mounting boss 53. Is located on the left front side of the cylinder bore 21, and the seating surface 52a of the first inner bolt mounting boss 52 and the seating surface 53a of the second inner bolt mounting boss 53 pass through the axial center of the camshaft 84.
- the bearing surface 56a of the first outer bolt mounting boss 56 is located on the right rear of the cylinder bore 21, and the bearing surface 57a of the second outer bolt mounting boss 57 is located on the right front of the cylinder bore 21, and the first outer bolt mounting boss is
- the seating surface 56a of the portion 56 and the seating surface 57a of the second outer bolt mounting boss 57 are disposed substantially symmetrically with respect to the camshaft center axis C2.
- the bearing surfaces 52a, 53a, 56a, 57a of the bolt mounting bosses 52, 53, 56, 57 are first inner bolts when viewed in the cylinder center axis C1 direction.
- the left end 21a of the cylinder bore 21 is positioned between the bearing surface 52a of the mounting boss 52 and the bearing surface 53a of the second inner bolt mounting boss 53, and the first outer bolt mounting of the bearing surface 52a of the first inner bolt mounting boss 52
- the rear end 21 b of the cylinder bore 21 is located between the bearing surface 56 a of the boss 56 and the bearing surface 53 a of the second inner bolt mounting boss 53 and the bearing surface 57 a of the second outer bolt mounting boss 57.
- the front end 21d approaches the cylinder bore 21 so that the right end 21c of the cylinder bore 21 is positioned between the seating surface 56a of the first outer bolt mounting boss 56 and the seating surface 57a of the second outer bolt mounting boss 57 respectively.
- the region between the first outer bolt mounting boss 56 and the second outer bolt mounting boss 57 is a spark plug mounting boss to which the spark plug 39 is mounted. It is formed as 59.
- the spark plug mounting boss 59 is formed with a spark plug hole 59 a opening toward the combustion chamber 33.
- the spark plug 39 is inserted into the spark plug hole 59 a, and the tip of the spark plug 39 is disposed facing the combustion chamber 33.
- the spark plug mounting boss 59 and the outer bolt mounting boss 55 are integrated. As it can be made smaller and the cylinder head 3 can be made smaller and lighter, the heat capacity of the spark plug mounting boss 59 and the outer bolt mounting boss 55 can be reduced to improve the cooling effect of the spark plug 39. It has become.
- the chain sprocket mechanism 90 which is the above-described transmission mechanism, has a cylinder bore 21 in the left-right direction, which is the direction of the camshaft center axis C2, from the outer bolt mounting boss 55 in the cylinder center axis C1 direction. Is placed on the other side across the. Therefore, even in the internal combustion engine E provided with the OHC type valve operating mechanism 80, the outer bolt mounting boss portion 55 can be used as the cylinder head 3 without considering the space required for the arrangement and maintenance of the chain sprocket mechanism 90 which is the transmission mechanism. It can be formed close to the right side wall 30R, and a working space around the stud bolt 70 can be secured.
- the front half and the rear half of the upper half of the right side wall 30R that separates the valve operating mechanism 80 from the outer bolt mounting boss 55 The head is concavely curved inward to avoid the bearing surface 56a of the first outer bolt mounting boss 56 which is the outer bolt mounting boss 55 and the bearing surface 57a of the second bolt mounting boss 57 in a direction view It is formed as a side recess 35.
- the head-side recess 35 is located to the left of the bearing surface 56a of the first outer bolt mounting boss 56 and the bearing surface 57a of the second outer bolt mounting boss 57 in the direction of the cylinder center axis C1.
- the side recess 35 is formed in a substantially concentric circular arc shape with the seat surface 56 a of the first outer bolt mounting boss 56 and the head side recess 35 on the front side with the seat 57 a of the second outer bolt mounting boss 57. Further, as shown in FIG. 2 by hatching, the head-side recess 35 is located obliquely forward and upward along the cylinder center axis C1 with respect to the bearing surface 55a of the outer bolt mounting boss 55 in a side view.
- the head-side recess 35 is curved with substantially the same thickness as the other outer peripheral wall 30 of the cylinder head 3, and the rigidity of the cylinder head 3 is extreme at the head-side recess 35. It does not fall.
- the bolt mounting boss 55 is a part of the cylinder bore 21 between the bearing surface 56 a of the first outer bolt mounting boss 56 and the bearing surface 57 a of the second outer bolt mounting boss 57 in the direction of the cylinder center axis C1. It can be disposed close to the periphery of the cylinder bore 21 to such an extent that a certain right end 21c is located.
- the width of the valve operating mechanism accommodation chamber 32 of the cylinder head 3 in the direction of the camshaft center axis C2 is made small, so that the cylinder head 3 can be miniaturized and reduced in weight. Further, in the direction of the cylinder center axis C1, the bearing surfaces 56a, 57a of the outer bolt mounting bosses 56, 57 and the right side wall 30R do not overlap, and the stud bolts 70 and fastening members attached to the outer bolt mounting boss 55 The tool space for the nut 71 is secured to improve maintainability.
- the first outer bolt mounting boss 56 is provided between the head-side recesses 35 on the head cover side end 3 d of the right side wall 30R of the cylinder head 3 as viewed in the direction of the cylinder center axis C1.
- a projecting portion 36 is formed between the second and second outer bolt mounting bosses 57 so as to project in a circular arc toward the right.
- An upper portion 34Ra of the right bearing portion 34R of the cylinder head 3 is disposed slightly to the right of the right bearing portion 34R on the valve operating mechanism accommodation chamber 32 side of the projecting portion 36.
- the formation of the projection 36 enables the rocker arm shaft 85 to be disposed further to the right, and the entire valve mechanism 80 to be disposed further to the right. Therefore, the width of the valve operating mechanism accommodation chamber 32 in the left-right direction, which is the direction of the camshaft axis center line C2, can be reduced, and further downsizing and weight reduction of the cylinder head 3 can be achieved.
- the height of the outer bolt mounting boss 55 in the direction of the cylinder center axis C1 is made lower than the ceiling walls 41b and 43b of the intake port 40 and the exhaust port 42 toward the cylinder block 2 as shown in FIG.
- wall portions 41 of the intake port 40 and the exhaust port 42 integrally formed with the right side wall 30R of the cylinder head 3 A part of 43 is exposed to the outside (right side of the cylinder head 3).
- a wall portion exposed to the right from the right side wall 30R of the cylinder head 3 (hereinafter referred to as the intake port wall exposed portion 41c) is a wall portion of the intake port 40 formed in a tubular shape.
- the intake port wall exposed portion 41c corresponds to the substantially right front half portion 41 of the right side wall 30R of the cylinder head 3 from the rear upper end of the spark plug mounting boss 59 and the upper end of the first outer bolt mounting boss 56 in a side view. It is exposed to the right of the cylinder head 3 over the rear end.
- a wall portion exposed to the right from the right side wall 30R of the cylinder head 3 (hereinafter referred to as the exhaust port wall exposed portion 43c) is formed of a cylindrical exhaust port 42.
- the exhaust port wall exposed portion 43c corresponds to the substantially right half portion of the wall portion 43, and the right side of the cylinder head 3 from the front upper end of the spark plug mounting boss 59 and the upper end of the second outer bolt mounting boss 57 in side view It is exposed on the right side of the cylinder head 3 across the front end of the wall 30R.
- the intake port wall exposed portion 41c and the exhaust port wall exposed portion 43c are exposed from the right side wall 30R of the cylinder head 3 to the right side of the cylinder head 3, whereby the intake port wall exposed portion 41c and the exhaust port wall exposed portion 43c also plays a role as a part of the right side wall 30R of the cylinder head 3.
- a plurality of cooling fins 37 are formed on the outer wall surface 3 a of the cylinder head 3.
- the cooling fins 37 are arranged in seven rows at substantially equal intervals from the cylinder block side end 3b of the cylinder head 3 to the head cover side end 3d in the direction of the cylinder center axis C1.
- the outer bolt mounting boss 55 seating surface 55a has the same height as the cooling fins 37 in the second row from the cylinder block side end 3b among the plurality of cooling fins 37 in the direction of the cylinder center axis C1.
- And is formed closer to the cylinder block 2 than a part of the cooling fins 37.
- the cooling fins 37 overlap the seating surface 56 a of the first outer bolt mounting boss 56 and the seating surface 57 a of the second outer bolt mounting boss 57 in the direction of the cylinder center axis C1. It is formed avoiding the area. Therefore, a tool space for the stud bolt 70 attached to the outer bolt attachment boss 55 and the nut 71 which is a fastening member is secured.
- the cooling fin 37 is a portion of the intake port 40 and the exhaust port 42 that is exposed to the right from the right side wall 30R of the cylinder head 3 among the walls 41 and 43 and the exhaust.
- the port wall exposed portion 43c is also formed. Therefore, it is possible to improve the cooling performance of the entire cylinder head 3 while reducing the size and weight of the cylinder head 3.
- a part of the cylinder block side end 30Lb of the left side wall 30L bulges toward the cam chain chamber 3c to form a bulging portion 44.
- a bolt insertion hole 44b through which a bolt 73 described later passes is formed at the front and rear of the bulging portion 44, and a seat surface 44a is formed at the upper opening surface of the bolt insertion hole 44b. It is done.
- Hexagon bolt heads 70c to be hung are respectively formed.
- the bolt 73 is a normal bolt having a screw portion 73a at its lower end and a hexagonal bolt head 73b at its upper end.
- the stud bolt 70 penetrates the bolt insertion hole 2b of the cylinder block 2 and the bolt insertion hole 50b of the cylinder head 3 to lower the threaded portion in the stud screw hole 1b of the crankcase 1.
- 70a is screwed and implanted.
- a nut 71 is screwed onto the upper screw portion 70b which protrudes from the bearing surface 52a, 53a, 56a, 57a of each bolt mounting boss 52, 53, 56, 57 to the head cover 6 side.
- the bearing surfaces 52a, 53a, 56a, 57a of the bolt mounting bosses 52, 53, 56, 57 are pressed through washers 72 and fixed to the bearing surfaces 52a, 53a, 56a, 57a. Further, the bolt 73 penetrates the bolt insertion hole 2 d of the cylinder block 2 and the bolt insertion hole 44 b of the cylinder head 3, and the threaded portion 73 a of the bolt 73 is screwed into the insertion screw hole 1 b of the crankcase 1. Are fixed to the bearing surface 44 a of the bulging portion 44 via
- the head cover 6 covering the valve operating mechanism accommodation chamber 32 of the cylinder head 3 covers the upper end of the substantially rectangular outer peripheral wall 61 and the outer peripheral wall 61 and faces the valve operating mechanism accommodating chamber 32. And the ceiling wall 63.
- a plurality of ribs 65 are formed on the outer side surface 63 a and the inner side surface 63 b of the ceiling wall 63 to increase the rigidity of the head cover 6.
- the end on the cylinder block side of the outer peripheral wall 61 of the head cover 6 is a flange portion 6a that bulges outward, and a boss portion 64 for a bolt 75 is provided at each of the four corners of the flange portion 6a. It is formed higher in the direction of the cylinder center axis C1 than the portion 6a.
- a bolt insertion hole 64 a is formed in the boss portion 64. As shown in FIG. 3, the bolt 75 penetrating the bolt insertion hole 64a through the washer 76 is screwed into the screw hole 3f formed in the head cover side mating surface 3e of the cylinder head 3, and the head cover 6 It is attached to the head 3.
- the first half and the second half in the front-rear direction of the right side wall 61 R are substantially in the center and the second half, respectively. It is formed as a cover-side recess 62 which is recessed so as to curve inward so as to avoid 56 and the second outer bolt mounting boss 57.
- the cover-side recess 62 is a cylinder so that the seat surface 56a of the first outer bolt mounting boss 56 and the seat surface 57a of the second outer bolt mounting boss 57 do not overlap with the right side wall 61R when viewed in the direction of the cylinder center axis C1. It is formed along the head-side recess 35 of the head 3. Further, as shown in FIGS.
- the cover-side concave portion 62 is most curved in the flange portion 6a, and formed so as to be slightly inclined inward from the flange portion 6a toward the ceiling wall 63. ing.
- a part of the right side wall 30R is a first outer bolt mounting boss 56 and a second outer bolt mounting boss which are outer bolt mounting bosses 55 when viewed in the direction of the cylinder center axis C1. It is formed as a head-side recess 35 that curves inward so as to avoid the 57 bearing surfaces 56a and 57a. According to such a configuration, the respective bearing surfaces 56a, 57a of the outer bolt mounting boss 55 can be disposed close to the periphery of the cylinder bore 21.
- the inside of the bolt attachment boss 50 is a part of the outer bolt attachment boss 55
- the valve operating mechanism housing chamber 32 can be made smaller by arranging the valve operating mechanism housing chamber 32 outside. Further, the right bulging portion 31 including the outer bolt mounting boss 55 can be formed small, and the width in the left-right direction of the cylinder head 3 can be reduced. Furthermore, the head side recess 35 formed in the right side wall 30R of the cylinder head 3 can secure a tool space for the stud bolt 70 and the nut 71 which is a fastening member, and can improve maintainability. Therefore, the cylinder head 3 can be miniaturized while maintaining the maintainability, and it is possible to provide the internal combustion engine E which is excellent in maintainability and reduced in size and weight.
- the bearing surfaces 56 a and 57 a of the outer bolt mounting boss 55 are located closer to the cylinder block 2 than a part of the plurality of cooling fins 37 in a side view, the cylinder center of the outer bolt mounting boss 55 The height in the direction of the axis C1 can be formed low, and the size and weight of the cylinder head 3 can be reduced. Further, since the cooling fins 37 are formed so as to avoid the area overlapping with the bearing surfaces 56a, 57a of the outer bolt mounting boss 55 in the direction of the cylinder center axis C1, the studs arranged in the outer bolt mounting boss 55 A tool space for the bolt 70 and the nut 71 which is a fastening member is secured, and maintainability can be secured.
- the internal combustion engine E is an OHC type internal combustion engine E in which a camshaft 84 is disposed in the valve operating mechanism accommodation chamber 32, and a chain sprocket mechanism 90 which is a transmission mechanism viewed from the cylinder center axis C1 direction. And 55 are disposed on the opposite side across the cylinder bore 21. Therefore, even in the case of the OHC type internal combustion engine E, the outer bolt attachment boss 55 can be formed close to the cylinder bore 21 without considering the space required for the arrangement and maintenance of the chain sprocket mechanism 90 which is the transmission mechanism. At the same time, the working space around the stud bolt 70 can be secured, and the maintainability can be further secured.
- the right side wall 30R of the cylinder head 3 is positioned such that the bearing surfaces 56a and 57a are positioned closer to the cylinder block 2 than the ceiling walls 41b and 43b of the intake port 40 and the exhaust port 42 in a side view. Is formed. Therefore, the height of the outer bolt mounting boss 55 in the direction of the cylinder center axis C1 can be reduced, and the outer bolt mounting boss 55 can be formed smaller, and the cylinder head 3 can be further miniaturized and lightened. Can be implemented.
- cooling fins 37 are formed on the intake port wall exposed portion 41c and the exhaust port wall exposed portion 43c, the cooling performance of the entire cylinder head 3 can be improved while achieving downsizing and weight reduction of the cylinder head 3. .
- the valve mechanism 80 As the internal combustion engine E becomes a two-valve internal combustion engine E in which the valve mechanism 80 includes one intake valve 81 and one exhaust valve 82, the valve mechanism 80 is miniaturized, and the cylinder head 3 Size and weight can be reduced. Further, since the outer bolt mounting boss 55 is disposed outside the valve operating mechanism accommodation chamber 32, the degree of freedom in the arrangement of the valve operating mechanism 80 is improved, and the intake and exhaust valves 81, 82 are set to the cylinder center axis C1. It is easy to arrange symmetrically, and the fuel combustion efficiency can be improved.
- a portion of the right side wall 61R is curved inward so as to avoid the outer bolt mounting boss 55 when viewed in the direction of the cylinder center axis C1. Since it is formed as the side recess 62, the tool space of the stud bolt 70 and the nut 71 arranged in the outer bolt mounting boss 55 can be formed also in the head cover 6, and the maintenance can be further improved.
- a notch 52c for lubricating oil discharge is formed in the bearing surface 52a of the first inner bolt mounting boss 52 which is the inner bolt mounting boss 51, a part of the plurality of bolt mounting bosses 50 is Even if disposed outside the valve operating mechanism accommodation chamber 32, the lubricating oil can be reliably supplied to the valve operating mechanism 80.
- an ignition plug mounting boss portion 59 is formed in which an ignition plug hole 59a for inserting and supporting the ignition plug 39 is formed. It is done. Therefore, the spark plug mounting boss portion 59 and the outer bolt mounting boss portion 55 are integrally formed small to achieve downsizing and weight reduction of the cylinder head 3, and the heat capacity of the spark plug mounting boss portion 59 and the outer bolt mounting boss portion 55. Can be reduced to improve the cooling effect of the spark plug 39.
- the transmission mechanism 90 is not limited to the cam chain sprocket mechanism, and may be a so-called cam gear mechanism using a plurality of gears instead of the cam chain 93.
- the head side recessed part 35 and the cover side recessed part 62 are formed in two places on the right side wall 30R of the cylinder head 3, you may form as one recessed part.
Landscapes
- Engineering & Computer Science (AREA)
- Chemical & Material Sciences (AREA)
- Combustion & Propulsion (AREA)
- Mechanical Engineering (AREA)
- General Engineering & Computer Science (AREA)
- Cylinder Crankcases Of Internal Combustion Engines (AREA)
Abstract
An internal combustion engine E is configured such that a cylinder block 2 and a cylinder head 3, in which a valve operation mechanism receiving chamber 32 for receiving a valve operation mechanism 80 is formed by the outer peripheral wall 30 of the cylinder head 3, are sequentially stacked on a crankcase 1, and the crankcase 1, the cylinder block 2, and the cylinder head 3 are fastened together by a plurality of stud bolts 70 and a plurality of fastening members 71, the plurality of stud bolts 70 and the plurality of fastening members 71 being arranged surrounding a cylinder bore 21 in the circumferential direction when viewed in the direction of the center axis C1 of the cylinder. The cylinder head 3 has formed thereon a plurality of bolt mounting boss sections 50 through which the stud bolts 70 pass respectively, the plurality of bolt mounting boss sections 50 consisting of inner bolt mounting boss sections 51 disposed inside the valve operation mechanism receiving chamber 32 in the cylinder head 3, the plurality of bolt mounting boss sections 50 further consisting of outer bolt mounting boss sections 55 disposed outside the valve operation mechanism receiving chamber 32. When viewed in the direction of the center axis C1 of the cylinder, portions of the outer peripheral wall 30 of the cylinder head 3 are recessed inward to form recesses 35 so that the outer peripheral wall 30 does not interfere with seat surfaces 56a, 57a for the fastening members 71, the seat surfaces 56a, 57a being located on the outer bolt mounting boss sections 55. The provided internal combustion engine can be maintained easily, is compact, and is lightweight.
Description
本発明は、シリンダヘッドが小型化された内燃機関に関する。
The present invention relates to an internal combustion engine in which a cylinder head is miniaturized.
従来、クランクケースにシリンダブロックおよびシリンダヘッドを重ねて複数のスタッドボルトにより一体に締結される内燃機関では、シリンダボアの周囲に配置されるスタッドボルトの取付けボス部は、シリンダヘッドに形成される動弁機構収容室内に配置されている。
このシリンダヘッドを小型化するために、複数のスタッドボルトの取付けボス部の内の一部をシリンダヘッドの動弁機構収容室の外に配置したものがある(特許文献1)。 Conventionally, in an internal combustion engine in which a cylinder block and a cylinder head are stacked on a crankcase and integrally fastened by a plurality of stud bolts, a mounting boss of the stud bolt disposed around the cylinder bore is a valve formed on the cylinder head It is arranged in the mechanism storage room.
In order to miniaturize the cylinder head, there is one in which a part of mounting bosses of a plurality of stud bolts is disposed outside a valve mechanism housing chamber of the cylinder head (Patent Document 1).
このシリンダヘッドを小型化するために、複数のスタッドボルトの取付けボス部の内の一部をシリンダヘッドの動弁機構収容室の外に配置したものがある(特許文献1)。 Conventionally, in an internal combustion engine in which a cylinder block and a cylinder head are stacked on a crankcase and integrally fastened by a plurality of stud bolts, a mounting boss of the stud bolt disposed around the cylinder bore is a valve formed on the cylinder head It is arranged in the mechanism storage room.
In order to miniaturize the cylinder head, there is one in which a part of mounting bosses of a plurality of stud bolts is disposed outside a valve mechanism housing chamber of the cylinder head (Patent Document 1).
特許文献1には、クランクケースに一体化されたシリンダに、動弁機構を収容する動弁機構収容室を有するシリンダヘッドが複数のスタッドボルトにより定着された空冷式のエンジン(内燃機関)が開示されている。
特許文献1に開示された内燃機関は、プッシュロッドを有するOHV方式の空冷式の内燃機関であり、動弁機構に用いられる部品点数が少なく、スタッドボルトの複数の取付けボス部の内の一部を動弁機構収容室の外に配置して動弁機構収容室を小さくすることで、シリンダヘッドの小型化を容易にすることができ、内燃機関の小型化が図られている。Patent Document 1 discloses an air-cooled engine (internal combustion engine) in which a cylinder head having a valve operating mechanism accommodation chamber for accommodating a valve operating mechanism is fixed by a plurality of stud bolts in a cylinder integrated with a crankcase. It is done.
The internal combustion engine disclosed inPatent Document 1 is an OHV air-cooled internal combustion engine having a push rod, which has a small number of parts used for a valve train, and is a part of a plurality of mounting bosses of a stud bolt. The cylinder head can be easily downsized by arranging the valve mechanism outside the valve operating mechanism accommodating chamber to make the valve operating mechanism accommodating chamber smaller, thereby achieving downsizing of the internal combustion engine.
特許文献1に開示された内燃機関は、プッシュロッドを有するOHV方式の空冷式の内燃機関であり、動弁機構に用いられる部品点数が少なく、スタッドボルトの複数の取付けボス部の内の一部を動弁機構収容室の外に配置して動弁機構収容室を小さくすることで、シリンダヘッドの小型化を容易にすることができ、内燃機関の小型化が図られている。
The internal combustion engine disclosed in
しかし、カムシャフトを有するOHC方式の内燃機関では、動弁機構に用いられる部品点数が多く、スタッドボルトの複数の取付けボス部の内の一部を動弁機構収容室の外に配置しても動弁機構収容室の小型化が容易ではない。また、スタッドボルトは、シリンダボア内の圧力を受けるためにシリンダボアの周囲に近づけてシリンダボアの周方向に均等に配置されることが望ましいが、スタッドボルトの複数の取付けボス部の内の一部を動弁機構収容室の外に配置する場合には、動弁機構、取付けボス部およびシリンダヘッドの壁部の配置が相互に干渉するため、取付けボス部をシリンダボアの周囲に近づけながら動弁機構収容室の外に配置することは容易ではない。さらに、シリンダヘッドを小型化すると、スタッドボルトのための工具スペースの確保等も考慮する必要がある。
However, in an OHC type internal combustion engine having a camshaft, the number of parts used in the valve operating mechanism is large, and even if a part of the plurality of mounting bosses of the stud bolt is arranged outside the valve operating mechanism accommodating chamber It is not easy to miniaturize the valve mechanism storage chamber. Also, although it is desirable for the stud bolts to be evenly distributed in the circumferential direction of the cylinder bore close to the circumference of the cylinder bore to receive the pressure in the cylinder bore, a portion of the plurality of mounting bosses of the stud bolt is moved When arranged outside the valve mechanism accommodating chamber, the valve operating mechanism, the mounting boss and the arrangement of the wall of the cylinder head interfere with each other, so the valve operating mechanism accommodating chamber is brought close to the periphery of the cylinder bore. It is not easy to put it outside. Furthermore, when the cylinder head is miniaturized, it is necessary to consider securing of a tool space for the stud bolt and the like.
本発明は、前記課題を解決するものであり、整備性が良好で、小型化および軽量化された内燃機関を提供することにある。
The present invention is to solve the above-mentioned problems, and an object of the present invention is to provide an internal combustion engine which has good maintainability, and which is reduced in size and weight.
前記課題を解決するため、本発明に係る内燃機関は、クランクケースと、内部にシリンダボアを有するシリンダブロックと、動弁機構を収容する動弁機構収容室を形成する外周壁を有しその外壁面に複数の冷却フィンが形成されるシリンダヘッドとを具備し、前記クランクケースに、前記シリンダブロックと前記シリンダヘッドとを順次重ねて複数のスタッドボルトおよび該スタッドボルトに取付ける締結部材により一体に締結し、複数の前記スタッドボルトを、前記シリンダボアの中心線を通るシリンダ中心軸線方向視で、前記シリンダボアを周方向に囲むように配置し、前記シリンダヘッドに、複数の前記スタッドボルトがそれぞれ貫通する複数のボルト取付けボス部を形成し、複数の前記ボルト取付けボス部は、前記シリンダヘッドの前記動弁機構収容室の内側に配置される内側ボルト取付けボス部と、前記シリンダヘッドの前記動弁機構収容室の外側に配置される外側ボルト取付けボス部とからなる内燃機関において、前記シリンダヘッドの前記外周壁は、前記シリンダ中心軸線方向視で、該外周壁の一部が前記外側ボルト取付けボス部の前記締結部材の座面を避けるように内側へ向けて凹んで形成された凹部を有することを特徴とする。
In order to solve the above-mentioned problems, an internal combustion engine according to the present invention has an outer peripheral wall having a crankcase, a cylinder block having a cylinder bore inside, and an outer peripheral wall forming a valve operating mechanism accommodating chamber for accommodating a valve operating mechanism. And a cylinder head having a plurality of cooling fins formed thereon, and the cylinder block and the cylinder head are sequentially stacked on the crankcase and integrally fastened by a plurality of stud bolts and fastening members attached to the stud bolts. A plurality of the stud bolts are arranged to circumferentially surround the cylinder bore in a cylinder center axis direction seen through a center line of the cylinder bore, and a plurality of the stud bolts pass through the cylinder head, respectively. A bolt mounting boss is formed, and the plurality of bolt mounting bosses are the cylinder head An internal combustion engine comprising: an inner bolt mounting boss portion disposed inside the valve operating mechanism housing chamber; and an outer bolt mounting boss portion disposed outside the valve operating mechanism housing chamber of the cylinder head. The outer peripheral wall has a recess formed so that a portion of the outer peripheral wall is recessed inward so as to avoid the bearing surface of the fastening member of the outer bolt mounting boss portion as viewed in the cylinder center axial direction. It is characterized by
この構成によれば、外側ボルト取付けボス部の座面をシリンダボアの周囲に近づけて配置することが可能となり、スタッドボルトをシリンダボアの周囲に略均等に近づけて配置しつつ、複数のボルト取付けボス部の一部を動弁機構収容室の外に配置することで動弁機構収容室を小さくすることができる。また、外側ボルト取付けボス部を含むシリンダブロックを小さくすることができる。さらに、外周壁にスタッドボルトおよび締結部材のための工具スペースを形成し、整備性を向上することができる。このように、動弁機構収容室および外側ボルト取付けボス部を小さく形成することでシリンダヘッドの小型化および軽量化が可能となり、整備性が良好で、小型化および軽量化された内燃機関を提供することができる。
According to this configuration, the bearing surface of the outer bolt mounting boss can be disposed close to the periphery of the cylinder bore, and the plurality of bolt mounting bosses can be disposed while the stud bolt is disposed approximately equally around the cylinder bore. By arranging a part of the valve outside the valve operating mechanism accommodating chamber, the valve operating mechanism accommodating chamber can be made smaller. Also, the cylinder block including the outer bolt mounting boss can be made smaller. Furthermore, tool spaces for stud bolts and fastening members can be formed on the outer peripheral wall to improve maintainability. As described above, by forming the valve operating mechanism chamber and the outer bolt mounting boss portion small, the cylinder head can be made smaller and lighter, and an internal combustion engine with good maintainability, smaller and lighter is provided. can do.
前記構成において、前記外側取付けボス部の前記座面が、側面視で、複数の前記冷却フィンの内、少なくとも一部の冷却フィンよりも前記シリンダブロック寄りに位置し、複数の前記冷却フィンを、前記シリンダ中心軸線方向視で、前記座面と重なる領域を避けて形成しても良い。
In the above configuration, the bearing surface of the outer attachment boss portion is located closer to the cylinder block than at least a part of the plurality of cooling fins in a side view, and the plurality of cooling fins are The region overlapping with the seat surface may be avoided when viewed in the cylinder center axis direction.
この構成によれば、動弁機構収容室の外にある外側ボルト取付けボス部の座面が冷却フィンの一部よりシリンダブロック寄りに位置しているために、外側ボルト取付けボス部のシリンダ中心軸線方向の高さを低くすることができ、シリンダヘッドの小型化および軽量化が可能となる。さらに、冷却フィンが、スタッドボルトのための工具スペースを避けて形成されるため、工具と冷却フィンとの干渉を回避することができる。そのため、整備性を確保しつつシリンダヘッドの小型化が可能となり、整備性が良好で、小型化および軽量化された内燃機関を提供することができる。
According to this configuration, the bearing surface of the outer bolt mounting boss outside the valve mechanism accommodation chamber is positioned closer to the cylinder block than a part of the cooling fin, so the cylinder center axis of the outer bolt mounting boss is The height of the direction can be reduced, and the cylinder head can be made smaller and lighter. Furthermore, since the cooling fins are formed avoiding the tool space for the stud bolts, interference between the tool and the cooling fins can be avoided. Therefore, it is possible to miniaturize the cylinder head while maintaining maintainability, and it is possible to provide an internal combustion engine which is excellent in maintainability and which is reduced in size and weight.
前記構成において、前記内燃機関を、前記動弁機構収容室にカムシャフトが配置されるOHC型内燃機関とし、前記カムシャフトに駆動力を伝達する伝達機構を、前記シリンダ中心軸線方向視で、前記外側ボルト取付けボス部とは前記シリンダボアを挟んで反対側に配置しても良い。
In the above-mentioned configuration, the internal combustion engine is an OHC type internal combustion engine in which a camshaft is disposed in the valve operating mechanism accommodation chamber, and a transmission mechanism for transmitting a driving force to the camshaft is the cylinder central axis view. The outer bolt mounting boss may be disposed on the opposite side of the cylinder bore.
この構成によれば、OHC型内燃機関であっても伝達機構の配設やメンテナンスに必要な空間を考慮することなく外側ボルト取付けボス部を形成することができるとともに、スタッドボルト周辺の作業空間を確保することが可能となり、さらに整備性を確保することができる。
According to this configuration, even in the case of an OHC internal combustion engine, the outer bolt mounting boss portion can be formed without considering the space required for the disposition and maintenance of the transmission mechanism, and the working space around the stud bolt It is possible to secure and further maintain maintainability.
前記構成において、前記シリンダヘッドには、吸気ポートと排気ポートとが設けられ、前記外側ボルトボス部の前記座面が、側面視で、前記吸気ポートおよび前記排気ポートの天井壁よりも前記シリンダブロック寄りに位置しても良い。
In the above configuration, the cylinder head is provided with an intake port and an exhaust port, and the bearing surface of the outer bolt boss portion is closer to the cylinder block than a ceiling wall of the intake port and the exhaust port in a side view. It may be located in
この構成によれば、外側ボルト取付けボス部をさらに小さくすることができ、シリンダヘッドの更なる小型化および軽量化が可能となる。
According to this configuration, the outer bolt mounting boss can be further reduced, and the cylinder head can be further reduced in size and weight.
前記構成において、前記冷却フィンを、前記吸気ポートおよび前記排気ポートの外壁面にも形成しても良い。
In the above configuration, the cooling fin may be formed on the outer wall surface of the intake port and the exhaust port.
この構成によれば、外側取付けボス部の座面を吸気ポートおよび排気ポートの天井面よりもシリンダブロック寄りに位置させたことで外部に露出した吸気ポートおよび排気ポートの壁部の外壁面に冷却フィンが形成されることとなる。そのため、シリンダヘッドの小型化および軽量化を図りつつ、シリンダヘッド全体の冷却性を向上させることができる。
According to this configuration, the outer attachment wall surface of the intake port and the exhaust port exposed to the outside is cooled by positioning the seat surface of the outer mounting boss portion closer to the cylinder block than the ceiling surface of the intake port and the exhaust port. Fins will be formed. Therefore, the cooling performance of the entire cylinder head can be improved while achieving downsizing and weight reduction of the cylinder head.
前記構成において、前記動弁機構は、一つの吸気バルブおよび一つの排気バルブを備えても良い。
In the above configuration, the valve mechanism may include one intake valve and one exhaust valve.
この構成によれば、内燃機関がいわゆる2バルブ式内燃機関となることで、動弁機構が小型化され、シリンダヘッドの更なる小型化および軽量化が可能となる。また、外側ボルト取付けボス部が動弁機構収容室の外に配置されていることから、動弁機構の配置の自由度が向上し、二つのバルブをシリンダ中心軸線に対して対称に配置させ易く、燃料の燃焼効率を向上させることができる。
According to this configuration, by making the internal combustion engine a so-called two-valve internal combustion engine, the valve train can be miniaturized, and the cylinder head can be further miniaturized and reduced in weight. In addition, since the outer bolt mounting boss portion is disposed outside the valve operating mechanism accommodation chamber, the degree of freedom in the arrangement of the valve operating mechanism is improved, and two valves can be easily arranged symmetrically with respect to the cylinder center axis. The fuel combustion efficiency can be improved.
前記構成において、前記シリンダヘッドには、前記動弁機構収容室を覆うヘッドカバーが取付けられ、該ヘッドカバーの外周壁は、前記シリンダ中心軸線方向視で、該ヘッドカバーの外周壁の一部を、前記外側ボルト取付けボス部の前記座面を避けるように内側へ向けて凹む凹部を形成しても良い。
In the above configuration, a head cover that covers the valve operating mechanism accommodation chamber is attached to the cylinder head, and an outer peripheral wall of the head cover is a part of the outer peripheral wall of the head cover in the axial direction of the cylinder center. A recess may be formed inward so as to avoid the bearing surface of the bolt mounting boss.
この構成によれば、外側ボルト取付けボス部に配置されるスタッドボルト周辺の工具スペースをヘッドカバーにも形成することができ、さらに整備性を向上することができる。
According to this configuration, the tool space around the stud bolt arranged in the outer bolt mounting boss can be formed also in the head cover, and the maintenance can be further improved.
前記構成において、前記内側ボルト取付けボス部の前記締結部材の座面の内、少なくとも一つの座面に、潤滑油排出用の切欠き部を設けても良い。
In the above-mentioned configuration, at least one of the seating surfaces of the fastening members of the inner bolt mounting boss may be provided with a cutout for discharging lubricating oil.
この構成によれば、複数のボルト取付けボス部の内の一部を動弁機構収容室の外に配置しても、内側ボルト取付けボス部から動弁機構への潤滑油の供給を確実に行うことができる。
According to this configuration, even if a part of the plurality of bolt mounting bosses is disposed outside the valve operating mechanism accommodation chamber, the lubricating oil is reliably supplied from the inner bolt mounting boss to the valve operating mechanism. be able to.
前記構成において、前記シリンダヘッドに、点火栓を挿通支持する点火栓孔を形成し、該点火栓孔は、前記外側ボルト取付けボス部の内、一対の外側ボルト取付けボス部の間に位置しても良い。
In the above configuration, the cylinder head is provided with a spark plug hole for inserting and supporting a spark plug, and the spark plug hole is positioned between a pair of outer bolt mounting bosses among the outer bolt mounting bosses. Also good.
この構成によれば、点火栓孔を外側ボルト取付けボス部の間に外側ボルト取付けボス部と一体に形成することが可能となり、シリンダヘッドの小型化および軽量化が図れるとともに、小さく形成される外側ボルト取付けボス部と一体に点火栓孔が形成されるために点火栓孔の周囲の熱容量が小さくなり点火栓の冷却効果を向上させることができる。
According to this configuration, the spark plug hole can be formed integrally with the outer bolt mounting boss portion between the outer bolt mounting boss portions, and the cylinder head can be made smaller and lighter, and the smaller outer side can be formed. Since the spark plug hole is formed integrally with the bolt mounting boss, the heat capacity around the spark plug hole can be reduced, and the cooling effect of the spark plug can be improved.
シリンダヘッドの動弁機構収容室の外にスタッドボルトのボルト取付けボス部が配置されて動弁機構収容室が小型化される。また、外側ボルト取付けボス部をシリンダボアに近づけて配置して小さく形成することができ、シリンダヘッドの小型化および軽量化が可能となる。さらに、シリンダヘッドの外周壁の一部が、スタッドボルトや締結部材のための工具スペースを避けて形成されるため、外側ボルト取付けボス部をシリンダヘッドの外周壁に隣接させることによる、工具と外周壁との干渉を回避することができる。そのため、整備性を確保しつつシリンダヘッドの小型化が可能となり、整備性が良好で、小型化および軽量化された内燃機関を提供することができる。
The bolt mounting boss portion of the stud bolt is disposed outside the valve operating mechanism accommodating chamber of the cylinder head to miniaturize the valve operating mechanism accommodating chamber. Further, the outer bolt mounting boss can be disposed close to the cylinder bore and can be formed small, and the cylinder head can be made smaller and lighter. Furthermore, since a part of the outer peripheral wall of the cylinder head is formed avoiding the stud bolt and the tool space for the fastening member, the tool and the outer peripheral can be obtained by making the outer bolt mounting boss portion adjacent to the outer peripheral wall of the cylinder head. Interference with the wall can be avoided. Therefore, it is possible to miniaturize the cylinder head while maintaining maintainability, and it is possible to provide an internal combustion engine which is excellent in maintainability and which is reduced in size and weight.
本発明の一実施の形態に係る内燃機関Eについて、図面を参照して以下に説明する。
本発明に係る内燃機関Eは、車両としての自動二輪車(不図示)に搭載されるSOHC型二バルブ式単気筒四ストローク内燃機関であり、車体(不図示)に対してクランク軸11を車体幅方向に指向させて車両に搭載されている。
なお、特許請求の範囲および本明細書の説明における前後、左右、上下の方向は、自動二輪車の向きに従うものとし、図中矢印FRは前方を、REは後方を、LTは左方を、RTは右方を、それぞれ示す。 An internal combustion engine E according to an embodiment of the present invention will be described below with reference to the drawings.
The internal combustion engine E according to the present invention is an SOHC type two-valve single-cylinder four-stroke internal combustion engine mounted on a motorcycle (not shown) as a vehicle, and thecrankshaft 11 is extended from the vehicle body (not shown). It is mounted on the vehicle with a directional orientation.
In the claims and in the description of this specification, the front, rear, left, right, and up and down directions follow the direction of the motorcycle. In the figure, arrow FR indicates the front, RE indicates the rear, LT indicates the left, and RT Indicates the right side, respectively.
本発明に係る内燃機関Eは、車両としての自動二輪車(不図示)に搭載されるSOHC型二バルブ式単気筒四ストローク内燃機関であり、車体(不図示)に対してクランク軸11を車体幅方向に指向させて車両に搭載されている。
なお、特許請求の範囲および本明細書の説明における前後、左右、上下の方向は、自動二輪車の向きに従うものとし、図中矢印FRは前方を、REは後方を、LTは左方を、RTは右方を、それぞれ示す。 An internal combustion engine E according to an embodiment of the present invention will be described below with reference to the drawings.
The internal combustion engine E according to the present invention is an SOHC type two-valve single-cylinder four-stroke internal combustion engine mounted on a motorcycle (not shown) as a vehicle, and the
In the claims and in the description of this specification, the front, rear, left, right, and up and down directions follow the direction of the motorcycle. In the figure, arrow FR indicates the front, RE indicates the rear, LT indicates the left, and RT Indicates the right side, respectively.
図1は、本発明の一実施の形態に係る内燃機関Eの一部断面とした左側面図であり、図2は、本発明の一実施の形態に係る内燃機関Eの一部拡大した右側面図であり、図3は、図2に示す内燃機関EのIII矢視による上面図である。
図1および図2に示されるように、内燃機関Eは、クランク軸11を回転自在に支承するクランクケース1と、一つのシリンダボア21を有するシリンダブロック2と、動弁機構80を収容する動弁機構収容室32を有するシリンダヘッド3と、シリンダヘッド3の動弁機構収容室32を覆うヘッドカバー6とを備えている。 FIG. 1 is a left side view of a partial cross section of an internal combustion engine E according to an embodiment of the present invention, and FIG. 2 is an enlarged right side of an internal combustion engine E according to an embodiment of the present invention. FIG. 3 is a top view of the internal combustion engine E shown in FIG.
As shown in FIGS. 1 and 2, the internal combustion engine E includes acrankcase 1 rotatably supporting a crankshaft 11, a cylinder block 2 having one cylinder bore 21, and a valve housing a valve mechanism 80. A cylinder head 3 having a mechanism accommodation chamber 32 and a head cover 6 covering a valve operating mechanism accommodation chamber 32 of the cylinder head 3 are provided.
図1および図2に示されるように、内燃機関Eは、クランク軸11を回転自在に支承するクランクケース1と、一つのシリンダボア21を有するシリンダブロック2と、動弁機構80を収容する動弁機構収容室32を有するシリンダヘッド3と、シリンダヘッド3の動弁機構収容室32を覆うヘッドカバー6とを備えている。 FIG. 1 is a left side view of a partial cross section of an internal combustion engine E according to an embodiment of the present invention, and FIG. 2 is an enlarged right side of an internal combustion engine E according to an embodiment of the present invention. FIG. 3 is a top view of the internal combustion engine E shown in FIG.
As shown in FIGS. 1 and 2, the internal combustion engine E includes a
クランクケース1の前部上方には、シリンダボア21の中心軸線を通るシリンダ中心軸線C1を斜め前方に傾斜させてシリンダブロック2が重ねられ、シリンダブロック2の上にガスケット(不図示)を介してシリンダヘッド3が重ねられ、スタッドボルト70によりこれらが一体に締結されている。図2および図3に示されるように、シリンダヘッド3の上にはヘッドカバー6が重ねられ、ヘッドカバー6はボルト75によりシリンダヘッド3に取付けられている。
The cylinder center axis C1 passing through the center axis of the cylinder bore 21 is obliquely inclined forward to the upper front of the crankcase 1 so that the cylinder block 2 is overlapped, and the cylinder (not shown) is interposed on the cylinder block 2 The heads 3 are overlapped, and these are fastened together by a stud bolt 70. As shown in FIGS. 2 and 3, a head cover 6 is superimposed on the cylinder head 3, and the head cover 6 is attached to the cylinder head 3 by bolts 75.
図1に示されるように、クランクケース1には、前半部中央にクランク軸11が回転自在に支承され、クランク軸11の後方には、メイン軸12とカウンタ軸13とが回転自在に支承されている。メイン軸12とカウンタ軸13との間には歯車式変速機構14が配置されている。図2に示されるように、クランク軸11の前斜め下方にはオイルポンプ17が配置されている。
As shown in FIG. 1, a crank shaft 11 is rotatably supported at the center of a front half of the crankcase 1, and a main shaft 12 and a counter shaft 13 are rotatably supported at the rear of the crank shaft 11. ing. A gear type transmission mechanism 14 is disposed between the main shaft 12 and the counter shaft 13. As shown in FIG. 2, an oil pump 17 is disposed at the lower front of the crankshaft 11.
図1に示されるように、シリンダブロック2のシリンダボア21には、ピストン22が往復摺動自在に嵌合されている。ピストン22は、ピストン22のピストンピン22aとクランク軸11のクランクピン11aとの間にコネクティングロッド15が連接されることで、クランク軸11に連結されている。図2に示されるように、シリンダブロック2の外壁面2aには、冷却フィン23が、外側に向って延出して複数形成されている。
As shown in FIG. 1, a piston 22 is slidably fitted in a cylinder bore 21 of the cylinder block 2 in a reciprocating manner. The piston 22 is connected to the crankshaft 11 by connecting the connecting rod 15 between the piston pin 22 a of the piston 22 and the crank pin 11 a of the crankshaft 11. As shown in FIG. 2, a plurality of cooling fins 23 are formed on the outer wall surface 2 a of the cylinder block 2 so as to extend outward.
図1に示されるように、ピストン22の頂面22bと、シリンダヘッド3の下部に設けられた燃焼室上壁部33aとの間には燃焼室33が形成されている。燃焼室上壁部33aには、吸気弁口33bと排気弁口33cとがそれぞれ一つずつシリンダ中心軸線C1を中心に互いに反対位置になるように燃焼室33に臨んで開口されている。吸気弁口33bからは吸気ポート40が、排気弁口33cからは排気ポート42がそれぞれ互いに離れる方向に、湾曲しながら延出して形成されている。
As shown in FIG. 1, a combustion chamber 33 is formed between the top surface 22 b of the piston 22 and the combustion chamber upper wall portion 33 a provided at the lower portion of the cylinder head 3. One intake valve port 33b and one exhaust valve port 33c are opened in the combustion chamber upper wall portion 33a so as to face the combustion chamber 33 at mutually opposite positions with respect to the cylinder center axis C1. An intake port 40 extends from the intake valve port 33b, and an exhaust port 42 extends from the exhaust valve port 33c in a direction away from each other while curving.
シリンダヘッド3の吸気弁口33bには吸気弁81が、排気弁口33cには排気弁82が、それぞれ取付けられている。吸気弁81と排気弁82は、燃焼室33に向ってシリンダ中心軸線C1に対して略対称になるように斜めに配置されている。
An intake valve 81 is attached to the intake valve port 33b of the cylinder head 3, and an exhaust valve 82 is attached to the exhaust valve port 33c. The intake valve 81 and the exhaust valve 82 are disposed obliquely to the combustion chamber 33 so as to be substantially symmetrical with respect to the cylinder center axis C1.
図4は、図3に示す内燃機関Eのヘッドカバー6を取外した状態の上面図であり、図5は、図4のV-V線断面図である。図4中、シリンダブロック2のシリンダボア21が網掛で表示されている。
図1に示されるように、吸気弁81と排気弁82は、それぞれが弁スプリング83により閉じる方向に付勢されており、図5に示されるようにシリンダヘッド3に配置される動弁機構80によってクランク軸11の回転に対して所定のタイミングで開閉される。 4 is a top view of the internal combustion engine E shown in FIG. 3 with thehead cover 6 removed, and FIG. 5 is a cross-sectional view taken along the line VV in FIG. In FIG. 4, the cylinder bores 21 of the cylinder block 2 are indicated by meshing.
As shown in FIG. 1, theintake valve 81 and the exhaust valve 82 are each biased in the closing direction by the valve spring 83, and the valve mechanism 80 disposed in the cylinder head 3 as shown in FIG. Thus, the opening and closing of the crankshaft 11 is performed at a predetermined timing.
図1に示されるように、吸気弁81と排気弁82は、それぞれが弁スプリング83により閉じる方向に付勢されており、図5に示されるようにシリンダヘッド3に配置される動弁機構80によってクランク軸11の回転に対して所定のタイミングで開閉される。 4 is a top view of the internal combustion engine E shown in FIG. 3 with the
As shown in FIG. 1, the
図4に示されるように、シリンダヘッド3は、シリンダ中心軸線C1方向視で略矩形状の外周壁30を有し、図1も参照して、シリンダヘッド3の外周壁30で囲われた空間の上部には動弁機構80が収容される前記動弁機構収容室32が形成されている。
As shown in FIG. 4, the cylinder head 3 has an outer peripheral wall 30 having a substantially rectangular shape in a direction of the cylinder center axis C1, and also referring to FIG. 1, a space surrounded by the outer peripheral wall 30 of the cylinder head 3. The valve operating mechanism accommodating chamber 32 in which the valve operating mechanism 80 is accommodated is formed in the upper part of the valve.
図1に示されるように、動弁機構80は、シリンダヘッド3の上部に一本のカムシャフト84が左右方向に指向して支持されるSOHC型の動弁機構80であり、カムシャフト84、ロッカーアーム軸85、吸気ロッカーアーム86および排気ロッカーアーム87を備えている。
As shown in FIG. 1, the valve operating mechanism 80 is an SOHC type valve operating mechanism 80 in which a single camshaft 84 is supported by being directed in the left-right direction on the upper portion of the cylinder head 3. A rocker arm shaft 85, an intake rocker arm 86 and an exhaust rocker arm 87 are provided.
図5に示されるように、シリンダヘッド3の燃焼室33の燃焼室上壁部33aの上部に左右方向に対向して左軸受部34Lと右軸受部34Rが上方に向って突出して形成されており、左右軸受部34L,34Rにベアリング(不図示)を介してカムシャフト84が回転自在に架設されている。
As shown in FIG. 5, a left bearing portion 34L and a right bearing portion 34R are formed so as to protrude upward facing the upper portion of the combustion chamber upper wall portion 33a of the combustion chamber 33 of the cylinder head 3 in the left-right direction. A camshaft 84 is rotatably mounted on the left and right bearing portions 34L, 34R via bearings (not shown).
カムシャフト84の上方には、一本のロッカーアーム軸85が、左右軸受部34L,34Rの上部34La,34Raにカムシャフト84と平行に架設されている。ロッカーアーム軸85には、吸気ロッカーアーム86と排気ロッカーアーム87とが隣接して搖動自在に支持されている。
Above the camshaft 84, a single rocker arm shaft 85 is mounted in parallel with the camshaft 84 on the upper portions 34La, 34Ra of the left and right bearing portions 34L, 34R. An intake rocker arm 86 and an exhaust rocker arm 87 are adjacently supported by the rocker arm shaft 85 so as to be freely pivotable.
シリンダヘッド3の外周壁30の左側壁30Lと左軸受部34Lとの間には、上下に貫通するカムチェーン室3cが形成されている。シリンダヘッド3の左軸受部34Lに設けられた図示されないベアリングを貫通したカムシャフト84の左端部84Lには、伝達機構であるチェーンスプロケット機構90の従動カムチェーンスプロケット92が嵌着されている。
Between the left side wall 30L of the outer peripheral wall 30 of the cylinder head 3 and the left bearing portion 34L, a cam chain chamber 3c penetrating vertically is formed. A driven cam chain sprocket 92 of a chain sprocket mechanism 90, which is a transmission mechanism, is fitted to a left end portion 84L of a camshaft 84 which penetrates a bearing (not shown) provided on the left bearing portion 34L of the cylinder head 3.
シリンダブロック2のシリンダボア21の左側には、シリンダヘッド3のカムチェーン室3cと連通するカムチェーン室2cが上下に貫通して形成されている。このシリンダブロック2のカムチェーン室2cを通って、カムチェーン93が、従動カムチェーンスプロケット92とクランク軸11に嵌着される駆動カムチェーンスプロケット(不図示)との間に架け渡されている。図1も参照して、ピストン22の摺動方向の動きにより回転駆動されるクランク軸11の回転駆動力が、チェーンスプロケット機構90を介してカムシャフト84に半分の回転数となって伝達され、カムシャフト84の回転に連動して吸気弁81および排気弁82がクランク軸11の回転に同期して開閉される。
On the left side of the cylinder bore 21 of the cylinder block 2, a cam chain chamber 2 c communicating with the cam chain chamber 3 c of the cylinder head 3 is formed penetrating vertically. A cam chain 93 is bridged between the driven cam chain sprocket 92 and a drive cam chain sprocket (not shown) fitted to the crankshaft 11 through the cam chain chamber 2 c of the cylinder block 2. Referring also to FIG. 1, the rotational driving force of the crankshaft 11, which is rotationally driven by the movement of the piston 22 in the sliding direction, is transmitted to the camshaft 84 at a half rotational speed via the chain sprocket mechanism 90. The intake valve 81 and the exhaust valve 82 are opened and closed in synchronization with the rotation of the crankshaft 11 in conjunction with the rotation of the camshaft 84.
図4および図5に示されるように、シリンダヘッド3は、シリンダ中心軸線C1方向視で、シリンダボア21の周囲を周方向に略均等に囲むように配置される四本のスタッドボルト70によってクランクケース1にシリンダブロック2とともに締結される。
As shown in FIGS. 4 and 5, the cylinder head 3 is crankcased by four stud bolts 70 arranged so as to circumferentially substantially equally surround the circumference of the cylinder bore 21 when viewed in the direction of the cylinder center axis C1. 1 and the cylinder block 2 are fastened together.
スタッドボルト70を取付けるボルト取付けボス部50は、図6に示されるように、シリンダ中心軸線C1方向視で、シリンダボア21の周囲を取り囲むようにシリンダヘッド3に四つ形成される。図5も参照して、ボルト取付けボス部50には、スタッドボルト70が貫通するボルト挿通孔50bが、シリンダ中心軸線C1方向に沿うように形成されている。ボルト取付けボス部50のボルト挿通孔50bの上部開口面は、スタッドボルト70を固定する締結部材であるナット71がワッシャ72を介して固定される円形状の座面50aとして形成されている。このように形成される四つのボルト挿通孔50bは、シリンダ中心軸線C1方向視で、シリンダボア21の周囲を周方向に略均等に取り囲む位置に配設される。
As shown in FIG. 6, four bolt mounting bosses 50 for mounting the stud bolts 70 are formed in the cylinder head 3 so as to surround the cylinder bore 21 as viewed in the direction of the cylinder center axis C1. Referring also to FIG. 5, in the bolt mounting boss 50, a bolt insertion hole 50b through which the stud bolt 70 passes is formed along the direction of the cylinder center axis C1. The upper opening surface of the bolt insertion hole 50b of the bolt mounting boss 50 is formed as a circular seating surface 50a to which a nut 71, which is a fastening member for fixing the stud bolt 70, is fixed via the washer 72. The four bolt insertion holes 50b formed in this manner are disposed at positions substantially equally surrounding the periphery of the cylinder bore 21 in the circumferential direction as viewed in the direction of the cylinder center axis C1.
図6に示されるように、ボルト取付けボス部50は、ボルト挿通孔50bを取り囲むように略円柱状に形成され、動弁機構収容室32の内側に配置される二つの内側ボルト取付けボス部51と、動弁機構収容室32の外側に配置される二つの外側ボルト取付けボス部55とからなっている。
As shown in FIG. 6, the bolt mounting bosses 50 are formed in a substantially cylindrical shape so as to surround the bolt insertion holes 50 b, and are provided with two inner bolt mounting bosses 51 disposed inside the valve mechanism accommodation chamber 32. And two outer bolt mounting bosses 55 disposed outside the valve operating mechanism housing 32.
内側ボルト取付けボス部51は、シリンダ中心軸線C1方向視で、シリンダボア21の左斜め後方に位置して左軸受部34Lと一体に形成される第一内側ボルト取付けボス部52と、シリンダボア21の左斜め前方に位置して左軸受部34Lと一体に形成される第二内側ボルト取付けボス部53とからなっている。図5も参照して、内側ボルト取付けボス部51の座面51aは、断面側方視でカムシャフト84とシリンダヘッド3のヘッドカバー側合わせ面3eとの間に位置している。
The inner bolt mounting boss portion 51 is located on the left diagonal rear of the cylinder bore 21 and is integrally formed with the left bearing portion 34L when viewed in the cylinder center axis C1 direction, and the left of the cylinder bore 21 A second inner bolt mounting boss 53 is formed obliquely with the front and integrally formed with the left bearing 34L. Referring also to FIG. 5, the bearing surface 51 a of the inner bolt mounting boss 51 is located between the camshaft 84 and the head cover side mating surface 3 e of the cylinder head 3 in a cross sectional side view.
図6に示されるように、第一内側ボルト取付けボス部52の座面52aには、ボルト挿通孔52bから径方向外方に位置する吸気弁81の上端に向って切欠かれた切欠き部52cが形成されている。第一内側ボルト取付けボス部52に形成されたボルト挿通孔52bは、クランクケース1に設けられるオイル供給路(不図示)に連通されてオイル供給路の一部を兼ねるようになっている。オイルポンプ17から供給されるオイルが、この切欠き部52cから動弁機構80に向けて吐出され、動弁機構80への潤滑油の供給を確実に行うことができるようになっている。
As shown in FIG. 6, in the seat surface 52a of the first inner bolt mounting boss 52, a notch 52c is cut out toward the upper end of the intake valve 81 located radially outward from the bolt insertion hole 52b. Is formed. The bolt insertion hole 52b formed in the first inner bolt mounting boss portion 52 is communicated with an oil supply passage (not shown) provided in the crankcase 1 and doubles as a part of the oil supply passage. The oil supplied from the oil pump 17 is discharged from the notch 52c toward the valve mechanism 80, so that lubricating oil can be reliably supplied to the valve mechanism 80.
図5および図6に示されるように、シリンダヘッド3の外周壁30の内、右側壁30Rのシリンダブロック側端部30Rbの前後方向における前半部略中央から後半部略中央までの領域が右側方へ膨出して右膨出部31が形成されている。右膨出部31には外側ボルト取付けボス部55が一体に形成されている。
As shown in FIGS. 5 and 6, in the outer peripheral wall 30 of the cylinder head 3, the region from the approximate center of the front half to the end of the rear half in the front-rear direction of the cylinder block side end 30Rb of the right side wall 30R The right bulging portion 31 is formed by bulging. An outer bolt mounting boss 55 is integrally formed on the right bulging portion 31.
図6に示されるように、外側ボルト取付けボス部55は、シリンダ中心軸線C1方向視で、シリンダボア21の右斜め後方に位置して右膨出部31の右後端に一体に形成される第一外側ボルト取付けボス部56と、シリンダボア21の右斜め前方に位置して右膨出部31の右前端に一体に形成される第二外側ボルト取付けボス部57とからなっている。図2に示されるように、外側ボルト取付けボス部55の座面55aは、側面視で、吸気ポート40の壁部41の天井壁41bおよび排気ポート42の壁部43の天井壁43bよりもシリンダブロック2側であって、シリンダ中心軸線C1方向においてシリンダヘッド3の下半部の略中央(すなわちシリンダヘッド3の略四分の一の高さ)に位置している。
As shown in FIG. 6, the outer bolt mounting boss 55 is positioned diagonally to the right rear of the cylinder bore 21 and integrally formed at the right rear end of the right bulging portion 31 in the direction of the cylinder center axis C1. It comprises an outer bolt mounting boss portion 56 and a second outer bolt mounting boss portion 57 positioned diagonally forward to the right of the cylinder bore 21 and integrally formed at the right front end of the right bulging portion 31. As shown in FIG. 2, the bearing surface 55 a of the outer bolt mounting boss 55 is more cylindrical than the ceiling wall 41 b of the wall 41 of the intake port 40 and the ceiling 43 b of the wall 43 of the exhaust port 42 in side view. It is located on the block 2 side, substantially in the center of the lower half of the cylinder head 3 in the direction of the cylinder center axis C1 (that is, approximately one-fourth the height of the cylinder head 3).
図6に示されるように、シリンダ中心軸線C1方向視で、第一内側ボルト取付けボス部52の座面52aはシリンダボア21の左後方に位置し、第二内側ボルト取付けボス部53の座面53aはシリンダボア21の左前方に位置し、第一内側ボルト取付けボス部52の座面52aと第二内側ボルト取付けボス部53の座面53aは、カムシャフト84の軸中心を通るカムシャフト中心軸線C2に対して略対称に配置される。第一外側ボルト取付けボス部56の座面56aはシリンダボア21の右後方に位置し、第二外側ボルト取付けボス部57の座面57aはシリンダボア21の右前方に位置し、第一外側ボルト取付けボス部56の座面56aと第二外側ボルト取付けボス部57の座面57aは、カムシャフト中心軸線C2に対して略対称に配置される。
As shown in FIG. 6, in the direction of the cylinder center axis C1, the bearing surface 52a of the first inner bolt mounting boss 52 is located on the left rear of the cylinder bore 21 and the bearing surface 53a of the second inner bolt mounting boss 53. Is located on the left front side of the cylinder bore 21, and the seating surface 52a of the first inner bolt mounting boss 52 and the seating surface 53a of the second inner bolt mounting boss 53 pass through the axial center of the camshaft 84. Are arranged substantially symmetrically with respect to The bearing surface 56a of the first outer bolt mounting boss 56 is located on the right rear of the cylinder bore 21, and the bearing surface 57a of the second outer bolt mounting boss 57 is located on the right front of the cylinder bore 21, and the first outer bolt mounting boss is The seating surface 56a of the portion 56 and the seating surface 57a of the second outer bolt mounting boss 57 are disposed substantially symmetrically with respect to the camshaft center axis C2.
図6に一点鎖線および網掛で示されるように、各ボルト取付けボス部52,53,56,57の各座面52a,53a,56a,57aは、シリンダ中心軸線C1方向視で、第一内側ボルト取付けボス部52の座面52aと第二内側ボルト取付けボス部53の座面53aの間にシリンダボア21の左端部21aが、第一内側ボルト取付けボス部52の座面52aと第一外側ボルト取付けボス部56の座面56aの間にシリンダボア21の後端部21bが、第二内側ボルト取付けボス部53の座面53aと第二外側ボルト取付けボス部57の座面57aの間にシリンダボア21の前端部21dが、第一外側ボルト取付けボス部56の座面56aと第二外側ボルト取付けボス部57の座面57aの間にシリンダボア21の右端部21cが、それぞれ位置するようにシリンダボア21に近づけてシリンダボア21の周囲に略均等に配置されている。
As shown by alternate long and short dashed lines and hatching in FIG. 6, the bearing surfaces 52a, 53a, 56a, 57a of the bolt mounting bosses 52, 53, 56, 57 are first inner bolts when viewed in the cylinder center axis C1 direction. The left end 21a of the cylinder bore 21 is positioned between the bearing surface 52a of the mounting boss 52 and the bearing surface 53a of the second inner bolt mounting boss 53, and the first outer bolt mounting of the bearing surface 52a of the first inner bolt mounting boss 52 The rear end 21 b of the cylinder bore 21 is located between the bearing surface 56 a of the boss 56 and the bearing surface 53 a of the second inner bolt mounting boss 53 and the bearing surface 57 a of the second outer bolt mounting boss 57. The front end 21d approaches the cylinder bore 21 so that the right end 21c of the cylinder bore 21 is positioned between the seating surface 56a of the first outer bolt mounting boss 56 and the seating surface 57a of the second outer bolt mounting boss 57 respectively. Are arranged substantially equally around the cylinder bore 21
図6に示されるように、右膨出部31の内、第一外側ボルト取付けボス部56と第二外側ボルト取付けボス部57の間の領域は、点火栓39が取付けられる点火栓取付けボス部59として形成されている。点火栓取付けボス部59には、燃焼室33に向けて開口する点火栓孔59aが形成されている。図2に示されるように、点火栓孔59aには点火栓39が挿入され、点火栓39の先端が燃焼室33に臨んで配置される。このように点火栓39が第一外側ボルト取付けボス部56と第二外側ボルト取付けボス部57との間に配置されることで、点火栓取付けボス部59と外側ボルト取付けボス部55が一体に小さく形成されてシリンダヘッド3の小型化および軽量化が図れるとともに、点火栓取付けボス部59と外側ボルト取付けボス部55の熱容量を小さくして点火栓39の冷却効果を向上させることができるようになっている。
As shown in FIG. 6, in the region of the right bulging portion 31, the region between the first outer bolt mounting boss 56 and the second outer bolt mounting boss 57 is a spark plug mounting boss to which the spark plug 39 is mounted. It is formed as 59. The spark plug mounting boss 59 is formed with a spark plug hole 59 a opening toward the combustion chamber 33. As shown in FIG. 2, the spark plug 39 is inserted into the spark plug hole 59 a, and the tip of the spark plug 39 is disposed facing the combustion chamber 33. Thus, by arranging the spark plug 39 between the first outer bolt mounting boss 56 and the second outer bolt mounting boss 57, the spark plug mounting boss 59 and the outer bolt mounting boss 55 are integrated. As it can be made smaller and the cylinder head 3 can be made smaller and lighter, the heat capacity of the spark plug mounting boss 59 and the outer bolt mounting boss 55 can be reduced to improve the cooling effect of the spark plug 39. It has become.
図6に示されるように、前述した伝達機構であるチェーンスプロケット機構90は、シリンダ中心軸線C1方向視で、外側ボルト取付けボス部55とはカムシャフト中心軸線C2方向である左右方向において、シリンダボア21を挟んで反対側に配置される。そのため、OHC型の動弁機構80を備える内燃機関Eであっても伝達機構であるチェーンスプロケット機構90の配設やメンテナンスに必要な空間を考慮することなく外側ボルト取付けボス部55をシリンダヘッド3の右側壁30Rに近づけて形成することができるとともに、スタッドボルト70周辺の作業空間を確保することができるようになっている。
As shown in FIG. 6, the chain sprocket mechanism 90, which is the above-described transmission mechanism, has a cylinder bore 21 in the left-right direction, which is the direction of the camshaft center axis C2, from the outer bolt mounting boss 55 in the cylinder center axis C1 direction. Is placed on the other side across the. Therefore, even in the internal combustion engine E provided with the OHC type valve operating mechanism 80, the outer bolt mounting boss portion 55 can be used as the cylinder head 3 without considering the space required for the arrangement and maintenance of the chain sprocket mechanism 90 which is the transmission mechanism. It can be formed close to the right side wall 30R, and a working space around the stud bolt 70 can be secured.
シリンダヘッド3の外周壁30の内、動弁機構80と外側ボルト取付けボス部55とを隔てる右側壁30Rの上半部の前後方向における前半部略中央および後半部略中央は、シリンダ中心軸線C1方向視で、外側ボルト取付けボス部55である第一外側ボルト取付けボス部56の座面56aおよび第二ボルト取付けボス部57の座面57aを避けるように内側へ向けて湾曲するように凹むヘッド側凹部35として形成されている。
Of the outer peripheral wall 30 of the cylinder head 3, the front half and the rear half of the upper half of the right side wall 30R that separates the valve operating mechanism 80 from the outer bolt mounting boss 55 The head is concavely curved inward to avoid the bearing surface 56a of the first outer bolt mounting boss 56 which is the outer bolt mounting boss 55 and the bearing surface 57a of the second bolt mounting boss 57 in a direction view It is formed as a side recess 35.
ヘッド側凹部35は、シリンダ中心軸線C1方向視で、第一外側ボルト取付けボス部56の座面56aおよび第二外側ボルト取付けボス部57の座面57aの左方に位置し、後側のヘッド側凹部35が第一外側ボルト取付けボス部56の座面56aと、前側のヘッド側凹部35が第二外側ボルト取付けボス部57の座面57aとそれぞれ略同心円弧状に形成されている。また、図2に網掛にて示されるように、ヘッド側凹部35は、側面視で、外側ボルト取付けボス部55の座面55aよりもシリンダ中心軸線C1に沿う斜め前上方に位置するシリンダヘッド3の右側壁30Rの上半部にシリンダ中心軸線C1に沿って形成されている。なお、図6に示されるように、ヘッド側凹部35は、シリンダヘッド3の他の外周壁30と略同じ厚みを有して湾曲し、シリンダヘッド3の剛性がヘッド側凹部35にて極端に低下しないようになっている。
The head-side recess 35 is located to the left of the bearing surface 56a of the first outer bolt mounting boss 56 and the bearing surface 57a of the second outer bolt mounting boss 57 in the direction of the cylinder center axis C1. The side recess 35 is formed in a substantially concentric circular arc shape with the seat surface 56 a of the first outer bolt mounting boss 56 and the head side recess 35 on the front side with the seat 57 a of the second outer bolt mounting boss 57. Further, as shown in FIG. 2 by hatching, the head-side recess 35 is located obliquely forward and upward along the cylinder center axis C1 with respect to the bearing surface 55a of the outer bolt mounting boss 55 in a side view. Is formed along the cylinder center axis C1 in the upper half of the right side wall 30R. As shown in FIG. 6, the head-side recess 35 is curved with substantially the same thickness as the other outer peripheral wall 30 of the cylinder head 3, and the rigidity of the cylinder head 3 is extreme at the head-side recess 35. It does not fall.
このようにヘッド側凹部35が形成されることで、前述したように、ボルト取付けボス部50の一部を外側ボルト取付けボス部55として動弁機構収容室32の外側に配置しても、外側ボルト取付けボス部55を、シリンダ中心軸線C1方向視で、第一外側ボルト取付けボス部56の座面56aと第二外側ボルト取付けボス部57の座面57aとの間にシリンダボア21の一部である右端部21cが位置する程度にシリンダボア21の周囲に近づけて配置することができる。そのため、シリンダヘッド3の動弁機構収容室32のカムシャフト中心軸線C2方向の幅を小さく形成してシリンダヘッド3の小型化および軽量化ができるようになっている。
また、シリンダ中心軸線C1方向視において、各外側ボルト取付けボス部56,57の座面56a,57aと右側壁30Rとが重ならず、外側ボルト取付けボス部55に取付けられるスタッドボルト70および締結部材であるナット71のための工具スペースが確保されて整備性が向上するようになっている。 By thus forming the head-side recess 35, as described above, even if a part of the bolt mounting boss 50 is disposed as the outer bolt mounting boss 55 outside the valve mechanism accommodation chamber 32, The bolt mounting boss 55 is a part of the cylinder bore 21 between the bearing surface 56 a of the first outer bolt mounting boss 56 and the bearing surface 57 a of the second outer bolt mounting boss 57 in the direction of the cylinder center axis C1. It can be disposed close to the periphery of the cylinder bore 21 to such an extent that a certain right end 21c is located. Therefore, the width of the valve operating mechanism accommodation chamber 32 of the cylinder head 3 in the direction of the camshaft center axis C2 is made small, so that the cylinder head 3 can be miniaturized and reduced in weight.
Further, in the direction of the cylinder center axis C1, the bearing surfaces 56a, 57a of the outer bolt mounting bosses 56, 57 and the right side wall 30R do not overlap, and the stud bolts 70 and fastening members attached to the outer bolt mounting boss 55 The tool space for the nut 71 is secured to improve maintainability.
また、シリンダ中心軸線C1方向視において、各外側ボルト取付けボス部56,57の座面56a,57aと右側壁30Rとが重ならず、外側ボルト取付けボス部55に取付けられるスタッドボルト70および締結部材であるナット71のための工具スペースが確保されて整備性が向上するようになっている。 By thus forming the head-
Further, in the direction of the cylinder center axis C1, the bearing
図5および図6に示されるように、シリンダヘッド3の右側壁30Rのヘッドカバー側端部3dのヘッド側凹部35の間には、シリンダ中心軸線C1方向視で、第一外側ボルト取付けボス部56と第二外側ボルト取付けボス部57との間に右側方へ向って円弧状に突出する突出部36が形成されている。突出部36の動弁機構収容室32側にはシリンダヘッド3の右軸受部34Rの上部34Raが右軸受部34Rよりもやや右寄りに配置されている。このように、突出部36が形成されることで、ロッカーアーム軸85をより右方へ配置することが可能となり、動弁機構80全体をより右方へ配置することが可能となる。そのため、カムシャフト軸中心線C2方向である左右方向における動弁機構収容室32の幅を小さくでき、シリンダヘッド3の更なる小型化、軽量化が図れるようになっている。
As shown in FIGS. 5 and 6, the first outer bolt mounting boss 56 is provided between the head-side recesses 35 on the head cover side end 3 d of the right side wall 30R of the cylinder head 3 as viewed in the direction of the cylinder center axis C1. A projecting portion 36 is formed between the second and second outer bolt mounting bosses 57 so as to project in a circular arc toward the right. An upper portion 34Ra of the right bearing portion 34R of the cylinder head 3 is disposed slightly to the right of the right bearing portion 34R on the valve operating mechanism accommodation chamber 32 side of the projecting portion 36. Thus, the formation of the projection 36 enables the rocker arm shaft 85 to be disposed further to the right, and the entire valve mechanism 80 to be disposed further to the right. Therefore, the width of the valve operating mechanism accommodation chamber 32 in the left-right direction, which is the direction of the camshaft axis center line C2, can be reduced, and further downsizing and weight reduction of the cylinder head 3 can be achieved.
前述したように、外側ボルト取付けボス部55のシリンダ中心軸線C1方向の高さを吸気ポート40および排気ポート42の天井壁41b,43bよりもシリンダブロック2側へ低くしたことで、図2に示されるように、シリンダヘッド3の外周壁30の内、右側壁30Rの下半部には、シリンダヘッド3の右側壁30Rと一体に形成されている吸気ポート40および排気ポート42の壁部41,43の一部が外部(シリンダヘッド3の右側方)に露出している。
As described above, the height of the outer bolt mounting boss 55 in the direction of the cylinder center axis C1 is made lower than the ceiling walls 41b and 43b of the intake port 40 and the exhaust port 42 toward the cylinder block 2 as shown in FIG. As described above, in the lower half of the right side wall 30R of the outer peripheral wall 30 of the cylinder head 3, wall portions 41 of the intake port 40 and the exhaust port 42 integrally formed with the right side wall 30R of the cylinder head 3 A part of 43 is exposed to the outside (right side of the cylinder head 3).
吸気ポート40の壁部41の内、シリンダヘッド3の右側壁30Rから右側方へ露出する壁部(以下、吸気ポート壁露出部41cという)は、筒状に形成される吸気ポート40の壁部41の略右前半部に相当し、吸気ポート壁露出部41cは、側面視で点火栓取付けボス部59の後部上端および第一外側ボルト取付けボス部56の上端からシリンダヘッド3の右側壁30Rの後端に亘ってシリンダヘッド3の右側方に露出している。
また、排気ポート42の壁部43の内、シリンダヘッド3の右側壁30Rから右側方へ露出する壁部(以下、排気ポート壁露出部43cという)は、筒状に形成される排気ポート42の壁部43の略右半部に相当し、排気ポート壁露出部43cは、側面視で点火栓取付けボス部59の前部上端および第二外側ボルト取付けボス部57の上端からシリンダヘッド3の右側壁30Rの前端に亘ってシリンダヘッド3の右側方に露出している。
このように、吸気ポート壁露出部41cと排気ポート壁露出部43cがシリンダヘッド3の右側壁30Rからシリンダヘッド3の右側方へ露出することで、吸気ポート壁露出部41cと排気ポート壁露出部43cは、シリンダヘッド3の右側壁30Rの一部としての役割も果たしている。 Among thewall portions 41 of the intake port 40, a wall portion exposed to the right from the right side wall 30R of the cylinder head 3 (hereinafter referred to as the intake port wall exposed portion 41c) is a wall portion of the intake port 40 formed in a tubular shape. The intake port wall exposed portion 41c corresponds to the substantially right front half portion 41 of the right side wall 30R of the cylinder head 3 from the rear upper end of the spark plug mounting boss 59 and the upper end of the first outer bolt mounting boss 56 in a side view. It is exposed to the right of the cylinder head 3 over the rear end.
Further, among the wall portions 43 of theexhaust port 42, a wall portion exposed to the right from the right side wall 30R of the cylinder head 3 (hereinafter referred to as the exhaust port wall exposed portion 43c) is formed of a cylindrical exhaust port 42. The exhaust port wall exposed portion 43c corresponds to the substantially right half portion of the wall portion 43, and the right side of the cylinder head 3 from the front upper end of the spark plug mounting boss 59 and the upper end of the second outer bolt mounting boss 57 in side view It is exposed on the right side of the cylinder head 3 across the front end of the wall 30R.
Thus, the intake port wall exposed portion 41c and the exhaust port wall exposed portion 43c are exposed from theright side wall 30R of the cylinder head 3 to the right side of the cylinder head 3, whereby the intake port wall exposed portion 41c and the exhaust port wall exposed portion 43c also plays a role as a part of the right side wall 30R of the cylinder head 3.
また、排気ポート42の壁部43の内、シリンダヘッド3の右側壁30Rから右側方へ露出する壁部(以下、排気ポート壁露出部43cという)は、筒状に形成される排気ポート42の壁部43の略右半部に相当し、排気ポート壁露出部43cは、側面視で点火栓取付けボス部59の前部上端および第二外側ボルト取付けボス部57の上端からシリンダヘッド3の右側壁30Rの前端に亘ってシリンダヘッド3の右側方に露出している。
このように、吸気ポート壁露出部41cと排気ポート壁露出部43cがシリンダヘッド3の右側壁30Rからシリンダヘッド3の右側方へ露出することで、吸気ポート壁露出部41cと排気ポート壁露出部43cは、シリンダヘッド3の右側壁30Rの一部としての役割も果たしている。 Among the
Further, among the wall portions 43 of the
Thus, the intake port wall exposed portion 41c and the exhaust port wall exposed portion 43c are exposed from the
図2に示されるように、シリンダヘッド3の外壁面3aには、冷却フィン37が複数形成されている。冷却フィン37は、シリンダ中心軸線C1方向において、シリンダヘッド3のシリンダブロック側端部3bからヘッドカバー側端部3dに亘って略等間隔に七列配列されている。そして、側面視において、外側ボルト取付けボス部55座面55aは、シリンダ中心軸線C1方向において、複数の冷却フィン37の内、シリンダブロック側端部3bから二列目の冷却フィン37と同じ高さに位置しており、一部の冷却フィン37よりもシリンダブロック2寄りに形成されていることとなる。
また、図6に示されるように、冷却フィン37は、シリンダ中心軸線C1方向視で、第一外側ボルト取付けボス部56の座面56aおよび第二外側ボルト取付けボス部57の座面57aと重なる領域を避けて形成されている。そのため、外側ボルト取付けボス部55に取付けられるスタッドボルト70および締結部材であるナット71のための工具スペースが確保されるようになっている。 As shown in FIG. 2, a plurality of coolingfins 37 are formed on the outer wall surface 3 a of the cylinder head 3. The cooling fins 37 are arranged in seven rows at substantially equal intervals from the cylinder block side end 3b of the cylinder head 3 to the head cover side end 3d in the direction of the cylinder center axis C1. In the side view, the outer bolt mounting boss 55 seating surface 55a has the same height as the cooling fins 37 in the second row from the cylinder block side end 3b among the plurality of cooling fins 37 in the direction of the cylinder center axis C1. , And is formed closer to the cylinder block 2 than a part of the cooling fins 37.
Further, as shown in FIG. 6, the coolingfins 37 overlap the seating surface 56 a of the first outer bolt mounting boss 56 and the seating surface 57 a of the second outer bolt mounting boss 57 in the direction of the cylinder center axis C1. It is formed avoiding the area. Therefore, a tool space for the stud bolt 70 attached to the outer bolt attachment boss 55 and the nut 71 which is a fastening member is secured.
また、図6に示されるように、冷却フィン37は、シリンダ中心軸線C1方向視で、第一外側ボルト取付けボス部56の座面56aおよび第二外側ボルト取付けボス部57の座面57aと重なる領域を避けて形成されている。そのため、外側ボルト取付けボス部55に取付けられるスタッドボルト70および締結部材であるナット71のための工具スペースが確保されるようになっている。 As shown in FIG. 2, a plurality of cooling
Further, as shown in FIG. 6, the cooling
図2に示されるように、冷却フィン37は、吸気ポート40および排気ポート42の壁部41,43の内、シリンダヘッド3の右側壁30Rから右側方へ露出する吸気ポート壁露出部41cおよび排気ポート壁露出部43cにも形成されている。そのため、シリンダヘッド3の小型化および軽量化を図りつつ、シリンダヘッド3全体の冷却性を向上させることができるようになっている。
As shown in FIG. 2, the cooling fin 37 is a portion of the intake port 40 and the exhaust port 42 that is exposed to the right from the right side wall 30R of the cylinder head 3 among the walls 41 and 43 and the exhaust. The port wall exposed portion 43c is also formed. Therefore, it is possible to improve the cooling performance of the entire cylinder head 3 while reducing the size and weight of the cylinder head 3.
図5に示されるように、シリンダヘッド3の外周壁30の内、左側壁30Lのシリンダブロック側端部30Lbの一部がカムチェーン室3c側へ膨出して膨出部44が形成されている。
図6も参照して、この膨出部44の前部と後部とには後述するボルト73が貫通するボルト挿通孔44bが形成され、ボルト挿通孔44bの上部開口面には座面44aが形成されている。 As shown in FIG. 5, in the outerperipheral wall 30 of the cylinder head 3, a part of the cylinder block side end 30Lb of the left side wall 30L bulges toward the cam chain chamber 3c to form a bulging portion 44. .
Referring also to FIG. 6, abolt insertion hole 44b through which a bolt 73 described later passes is formed at the front and rear of the bulging portion 44, and a seat surface 44a is formed at the upper opening surface of the bolt insertion hole 44b. It is done.
図6も参照して、この膨出部44の前部と後部とには後述するボルト73が貫通するボルト挿通孔44bが形成され、ボルト挿通孔44bの上部開口面には座面44aが形成されている。 As shown in FIG. 5, in the outer
Referring also to FIG. 6, a
図5に示されるように、シリンダヘッド3に形成される六本のボルト挿通孔44b,50bに対応して、シリンダブロック2にはシリンダヘッド3のボルト挿通孔44b,50bと同軸にボルト挿通孔2b,2dが形成され、クランクケース1にはシリンダブロック2のボルト挿通孔2b,2dと同軸に植込みネジ穴1bが形成されている。
As shown in FIG. 5, corresponding to the six bolt insertion holes 44b, 50b formed in the cylinder head 3, bolt insertion holes in the cylinder block 2 coaxially with the bolt insertion holes 44b, 50b of the cylinder head 3 2b and 2d are formed, and an insertion screw hole 1b is formed in the crankcase 1 coaxially with the bolt insertion holes 2b and 2d of the cylinder block 2.
スタッドボルト70には、下端にクランクケース1の植込みネジ穴1bに螺合される下側ネジ部70aが、上端近傍に上側ネジ部70bが、上側ネジ部70bよりも上の上端には工具を掛ける六角ボルト頭部70cがそれぞれ形成されている。
ボルト73は、下端にネジ部73aが、上端に六角ボルト頭部73bが形成される通常のボルトである。 Thelower screw 70a screwed into the stud screw hole 1b of the crankcase 1 at the lower end of the stud bolt 70, the upper screw 70b near the upper end, and a tool at the upper end above the upper screw 70b. Hexagon bolt heads 70c to be hung are respectively formed.
Thebolt 73 is a normal bolt having a screw portion 73a at its lower end and a hexagonal bolt head 73b at its upper end.
ボルト73は、下端にネジ部73aが、上端に六角ボルト頭部73bが形成される通常のボルトである。 The
The
図4および図5に示されるように、スタッドボルト70は、シリンダブロック2のボルト挿通孔2bおよびシリンダヘッド3のボルト挿通孔50bを貫通してクランクケース1の植込みネジ穴1bに下側ネジ部70aが螺合されて植込まれる。また、スタッドボルト70は、各ボルト取付けボス部52,53,56,57の各座面52a,53a,56a,57aからヘッドカバー6側に突出する上側ネジ部70bにナット71が螺合されて、ワッシャ72を介して各ボルト取付けボス部52,53,56,57の各座面52a,53a,56a,57aを押圧して該座面52a,53a,56a,57aに固定されている。
また、ボルト73は、シリンダブロック2のボルト挿通孔2dおよびシリンダヘッド3のボルト挿通孔44bを貫通してクランクケース1の植込みネジ穴1bにボルト73のネジ部73aが螺合されて、ワッシャ74を介して膨出部44の座面44aに固定されている。 As shown in FIGS. 4 and 5, thestud bolt 70 penetrates the bolt insertion hole 2b of the cylinder block 2 and the bolt insertion hole 50b of the cylinder head 3 to lower the threaded portion in the stud screw hole 1b of the crankcase 1. 70a is screwed and implanted. Further, in the stud bolt 70, a nut 71 is screwed onto the upper screw portion 70b which protrudes from the bearing surface 52a, 53a, 56a, 57a of each bolt mounting boss 52, 53, 56, 57 to the head cover 6 side. The bearing surfaces 52a, 53a, 56a, 57a of the bolt mounting bosses 52, 53, 56, 57 are pressed through washers 72 and fixed to the bearing surfaces 52a, 53a, 56a, 57a.
Further, thebolt 73 penetrates the bolt insertion hole 2 d of the cylinder block 2 and the bolt insertion hole 44 b of the cylinder head 3, and the threaded portion 73 a of the bolt 73 is screwed into the insertion screw hole 1 b of the crankcase 1. Are fixed to the bearing surface 44 a of the bulging portion 44 via
また、ボルト73は、シリンダブロック2のボルト挿通孔2dおよびシリンダヘッド3のボルト挿通孔44bを貫通してクランクケース1の植込みネジ穴1bにボルト73のネジ部73aが螺合されて、ワッシャ74を介して膨出部44の座面44aに固定されている。 As shown in FIGS. 4 and 5, the
Further, the
図3および図5に示されるように、シリンダヘッド3の動弁機構収容室32を覆うヘッドカバー6は、略矩形の外周壁61と、外周壁61の上端を覆い動弁機構収容室32に対向する天井壁63とからなっている。天井壁63の外側面63aおよび内側面63bには、複数のリブ65が形成されており、ヘッドカバー6の剛性を高めている。
As shown in FIGS. 3 and 5, the head cover 6 covering the valve operating mechanism accommodation chamber 32 of the cylinder head 3 covers the upper end of the substantially rectangular outer peripheral wall 61 and the outer peripheral wall 61 and faces the valve operating mechanism accommodating chamber 32. And the ceiling wall 63. A plurality of ribs 65 are formed on the outer side surface 63 a and the inner side surface 63 b of the ceiling wall 63 to increase the rigidity of the head cover 6.
ヘッドカバー6の外周壁61のシリンダブロック側の端部は、外側に向って膨出するフランジ部6aとなっており、フランジ部6aの四隅のそれぞれにはボルト75のためのボス部64が、フランジ部6aよりもシリンダ中心軸線C1方向に高く形成されている。ボス部64にはボルト挿通孔64aが形成されている。図3に示されるように、ワッシャ76を介してボルト挿通孔64aを貫通したボルト75が、シリンダヘッド3のヘッドカバー側合わせ面3eに形成されるネジ穴3fに螺合されて、ヘッドカバー6はシリンダヘッド3に取付けられている。
The end on the cylinder block side of the outer peripheral wall 61 of the head cover 6 is a flange portion 6a that bulges outward, and a boss portion 64 for a bolt 75 is provided at each of the four corners of the flange portion 6a. It is formed higher in the direction of the cylinder center axis C1 than the portion 6a. A bolt insertion hole 64 a is formed in the boss portion 64. As shown in FIG. 3, the bolt 75 penetrating the bolt insertion hole 64a through the washer 76 is screwed into the screw hole 3f formed in the head cover side mating surface 3e of the cylinder head 3, and the head cover 6 It is attached to the head 3.
図3に示されるように、ヘッドカバー6の外周壁61の内、右側壁61Rの前後方向における前半部略中央および後半部略中央は、シリンダ中心軸線C1方向視で、第一外側ボルト取付けボス部56および第二外側ボルト取付けボス部57を避けるように内側へ向けて湾曲するように凹むカバー側凹部62として形成されている。カバー側凹部62は、シリンダ中心軸線C1方向視で、第一外側ボルト取付けボス部56の座面56aおよび第二外側ボルト取付けボス部57の座面57aと右側壁61Rとが重ならないようにシリンダヘッド3のヘッド側凹部35に沿って形成されている。また、図3および図5に示されるように、カバー側凹部62は、フランジ部6aにおいて最も湾曲し、フランジ部6aから天井壁63へ向かうに連れて内側へ向けてやや傾斜するように形成されている。このようにカバー側凹部62が形成されることで、外側ボルト取付けボス部55に締結されるスタッドボルト70および締結部材であるナット71のための工具スペースが確保され、整備性を確保することができるようになっている。
As shown in FIG. 3, of the outer peripheral wall 61 of the head cover 6, the first half and the second half in the front-rear direction of the right side wall 61 R are substantially in the center and the second half, respectively. It is formed as a cover-side recess 62 which is recessed so as to curve inward so as to avoid 56 and the second outer bolt mounting boss 57. The cover-side recess 62 is a cylinder so that the seat surface 56a of the first outer bolt mounting boss 56 and the seat surface 57a of the second outer bolt mounting boss 57 do not overlap with the right side wall 61R when viewed in the direction of the cylinder center axis C1. It is formed along the head-side recess 35 of the head 3. Further, as shown in FIGS. 3 and 5, the cover-side concave portion 62 is most curved in the flange portion 6a, and formed so as to be slightly inclined inward from the flange portion 6a toward the ceiling wall 63. ing. By thus forming the cover-side concave portion 62, a tool space for the stud bolt 70 and the nut 71 which is a fastening member to be fastened to the outer bolt attachment boss 55 is secured, and maintainability is ensured. It can be done.
また、シリンダヘッド3と同様に、カバー側凹部62の間には、シリンダ中心軸線C1方向視で、第一外側ボルト取付けボス部56と第二外側ボルト取付けボス部57との間に円弧状に突出する突出部66が形成されている。突出部66の内側には、シリンダヘッド3からヘッドカバー6内に延出される右軸受部34Rの上部34Raが配置されている。そのため、ロッカーアーム軸85をより右方へ配置することが可能となりヘッドカバー6の左右方向の幅が小さくなり、内燃機関Eの更なる小型化、軽量化が図れるようになっている。
Further, similarly to the cylinder head 3, between the cover-side concave portions 62, in a circular direction between the first outer bolt mounting boss portion 56 and the second outer bolt mounting boss portion 57 in the direction of the cylinder center axis C1. A protruding protrusion 66 is formed. An upper portion 34Ra of the right bearing portion 34R, which extends from the cylinder head 3 into the head cover 6, is disposed inside the protrusion 66. Therefore, the rocker arm shaft 85 can be disposed further to the right, the width in the left-right direction of the head cover 6 is reduced, and further downsizing and weight reduction of the internal combustion engine E can be achieved.
以上、詳細に説明した本発明に係る内燃機関の一実施の形態では、以下の効果を奏する。
シリンダヘッド3の外周壁30の内、右側壁30Rの一部は、シリンダ中心軸線C1方向視で、外側ボルト取付けボス部55である第一外側ボルト取付けボス部56および第二外側ボルト取付けボス部57の座面56a,57aを避けるように内側へ向けて湾曲するヘッド側凹部35として形成されている。
このような構成によれば、外側ボルト取付けボス部55の各座面56a,57aをシリンダボア21の周囲に近づけて配置することができる。そのため、ボルト取付けボス部50のボルト挿通孔50bを貫通するスタッドボルト70をシリンダボア21の周囲に略均等に近づけて配置しつつ、ボルト取付けボス部50の内の一部を外側ボルト取付けボス部55として動弁機構収容室32の外に配置することで動弁機構収容室32を小さくすることができる。また、外側ボルト取付けボス部55を含む右膨出部31を小さく形成でき、シリンダヘッド3の左右方向の幅を小さくすることができる。さらに、シリンダヘッド3の右側壁30Rに形成されるヘッド側凹部35によりスタッドボルト70および締結部材であるナット71のための工具スペースを確保し、整備性を向上することができる。そのため、整備性を確保しつつシリンダヘッド3の小型化が可能となり、整備性が良好で、小型化および軽量化された内燃機関Eを提供することができる。 The following effects can be obtained from the embodiment of the internal combustion engine according to the present invention described above in detail.
Among the outerperipheral wall 30 of the cylinder head 3, a part of the right side wall 30R is a first outer bolt mounting boss 56 and a second outer bolt mounting boss which are outer bolt mounting bosses 55 when viewed in the direction of the cylinder center axis C1. It is formed as a head-side recess 35 that curves inward so as to avoid the 57 bearing surfaces 56a and 57a.
According to such a configuration, the respective bearing surfaces 56a, 57a of the outer bolt mounting boss 55 can be disposed close to the periphery of the cylinder bore 21. Therefore, while arranging the stud bolt 70 which penetrates the bolt insertion hole 50b of the bolt attachment boss 50 approximately equally around the cylinder bore 21, the inside of the bolt attachment boss 50 is a part of the outer bolt attachment boss 55 The valve operating mechanism housing chamber 32 can be made smaller by arranging the valve operating mechanism housing chamber 32 outside. Further, the right bulging portion 31 including the outer bolt mounting boss 55 can be formed small, and the width in the left-right direction of the cylinder head 3 can be reduced. Furthermore, the head side recess 35 formed in the right side wall 30R of the cylinder head 3 can secure a tool space for the stud bolt 70 and the nut 71 which is a fastening member, and can improve maintainability. Therefore, the cylinder head 3 can be miniaturized while maintaining the maintainability, and it is possible to provide the internal combustion engine E which is excellent in maintainability and reduced in size and weight.
シリンダヘッド3の外周壁30の内、右側壁30Rの一部は、シリンダ中心軸線C1方向視で、外側ボルト取付けボス部55である第一外側ボルト取付けボス部56および第二外側ボルト取付けボス部57の座面56a,57aを避けるように内側へ向けて湾曲するヘッド側凹部35として形成されている。
このような構成によれば、外側ボルト取付けボス部55の各座面56a,57aをシリンダボア21の周囲に近づけて配置することができる。そのため、ボルト取付けボス部50のボルト挿通孔50bを貫通するスタッドボルト70をシリンダボア21の周囲に略均等に近づけて配置しつつ、ボルト取付けボス部50の内の一部を外側ボルト取付けボス部55として動弁機構収容室32の外に配置することで動弁機構収容室32を小さくすることができる。また、外側ボルト取付けボス部55を含む右膨出部31を小さく形成でき、シリンダヘッド3の左右方向の幅を小さくすることができる。さらに、シリンダヘッド3の右側壁30Rに形成されるヘッド側凹部35によりスタッドボルト70および締結部材であるナット71のための工具スペースを確保し、整備性を向上することができる。そのため、整備性を確保しつつシリンダヘッド3の小型化が可能となり、整備性が良好で、小型化および軽量化された内燃機関Eを提供することができる。 The following effects can be obtained from the embodiment of the internal combustion engine according to the present invention described above in detail.
Among the outer
According to such a configuration, the
外側ボルト取付けボス部55の座面56a,57aが、側面視で、複数の冷却フィン37の内の一部よりもシリンダブロック2寄りに位置しているため、外側ボルト取付けボス部55のシリンダ中心軸線C1方向の高さを低く形成することができ、シリンダヘッド3の小型化および軽量化を図ることができる。
また、冷却フィン37が、シリンダ中心軸線C1方向視で、外側ボルト取付けボス部55の座面56a,57aと重なる領域を避けて形成されているため、外側ボルト取付けボス部55に配置されるスタッドボルト70および締結部材であるナット71のための工具スペースが確保され、整備性を確保することができる。 Since the bearing surfaces 56 a and 57 a of the outerbolt mounting boss 55 are located closer to the cylinder block 2 than a part of the plurality of cooling fins 37 in a side view, the cylinder center of the outer bolt mounting boss 55 The height in the direction of the axis C1 can be formed low, and the size and weight of the cylinder head 3 can be reduced.
Further, since the coolingfins 37 are formed so as to avoid the area overlapping with the bearing surfaces 56a, 57a of the outer bolt mounting boss 55 in the direction of the cylinder center axis C1, the studs arranged in the outer bolt mounting boss 55 A tool space for the bolt 70 and the nut 71 which is a fastening member is secured, and maintainability can be secured.
また、冷却フィン37が、シリンダ中心軸線C1方向視で、外側ボルト取付けボス部55の座面56a,57aと重なる領域を避けて形成されているため、外側ボルト取付けボス部55に配置されるスタッドボルト70および締結部材であるナット71のための工具スペースが確保され、整備性を確保することができる。 Since the bearing surfaces 56 a and 57 a of the outer
Further, since the cooling
内燃機関Eは、動弁機構収容室32にカムシャフト84が配置されるOHC型の内燃機関Eであり、伝達機構であるチェーンスプロケット機構90がシリンダ中心軸線C1方向視で、外側ボルト取付けボス部55とはシリンダボア21を挟んで反対側に配置されている。そのため、OHC型内燃機関Eであっても伝達機構であるチェーンスプロケット機構90の配設やメンテナンスに必要な空間を考慮することなく外側ボルト取付けボス部55をシリンダボア21に近づけて形成することができるとともに、スタッドボルト70周辺の作業空間を確保することが可能となり、さらに整備性を確保することができる。
The internal combustion engine E is an OHC type internal combustion engine E in which a camshaft 84 is disposed in the valve operating mechanism accommodation chamber 32, and a chain sprocket mechanism 90 which is a transmission mechanism viewed from the cylinder center axis C1 direction. And 55 are disposed on the opposite side across the cylinder bore 21. Therefore, even in the case of the OHC type internal combustion engine E, the outer bolt attachment boss 55 can be formed close to the cylinder bore 21 without considering the space required for the arrangement and maintenance of the chain sprocket mechanism 90 which is the transmission mechanism. At the same time, the working space around the stud bolt 70 can be secured, and the maintainability can be further secured.
外側ボルト取付けボス部55は、側面視で、座面56a,57aが吸気ポート40および排気ポート42の天井壁41b,43bよりもシリンダブロック2寄りに位置するように、シリンダヘッド3の右側壁30Rに形成されている。そのため、外側ボルト取付けボス部55の、シリンダ中心軸線C1方向における高さを低くすることが可能となり、外側ボルト取付けボス部55を小さく形成することができ、シリンダヘッド3の更なる小型化および軽量化を図ることができる。
The right side wall 30R of the cylinder head 3 is positioned such that the bearing surfaces 56a and 57a are positioned closer to the cylinder block 2 than the ceiling walls 41b and 43b of the intake port 40 and the exhaust port 42 in a side view. Is formed. Therefore, the height of the outer bolt mounting boss 55 in the direction of the cylinder center axis C1 can be reduced, and the outer bolt mounting boss 55 can be formed smaller, and the cylinder head 3 can be further miniaturized and lightened. Can be implemented.
冷却フィン37が、吸気ポート壁露出部41cと排気ポート壁露出部43cに形成されるため、シリンダヘッド3の小型化および軽量化を図りつつ、シリンダヘッド3全体の冷却性を向上させることができる。
Since the cooling fins 37 are formed on the intake port wall exposed portion 41c and the exhaust port wall exposed portion 43c, the cooling performance of the entire cylinder head 3 can be improved while achieving downsizing and weight reduction of the cylinder head 3. .
内燃機関Eが、動弁機構80に一つの吸気弁81および一つの排気弁82が備えられる2バルブ式の内燃機関Eとなることで、動弁機構80が小型化され、シリンダヘッド3の更なる小型化および軽量化が可能となる。また、外側ボルト取付けボス部55が動弁機構収容室32の外に配置されていることから、動弁機構80の配置の自由度が向上し、吸排気弁81,82をシリンダ中心軸線C1に対して対称に配置させ易く、燃料の燃焼効率を向上させることができる。
As the internal combustion engine E becomes a two-valve internal combustion engine E in which the valve mechanism 80 includes one intake valve 81 and one exhaust valve 82, the valve mechanism 80 is miniaturized, and the cylinder head 3 Size and weight can be reduced. Further, since the outer bolt mounting boss 55 is disposed outside the valve operating mechanism accommodation chamber 32, the degree of freedom in the arrangement of the valve operating mechanism 80 is improved, and the intake and exhaust valves 81, 82 are set to the cylinder center axis C1. It is easy to arrange symmetrically, and the fuel combustion efficiency can be improved.
動弁機構収容室32を覆うヘッドカバー6の外周壁61の内、右側壁61Rの一部は、シリンダ中心軸線C1方向視で、外側ボルト取付けボス部55を避けるように内側へ向けて湾曲するカバー側凹部62として形成されているため、外側ボルト取付けボス部55に配置されるスタッドボルト70およびナット71の工具スペースをヘッドカバー6にも形成することができ、さらに整備性を向上することができる。
Of the outer peripheral wall 61 of the head cover 6 covering the valve mechanism accommodation chamber 32, a portion of the right side wall 61R is curved inward so as to avoid the outer bolt mounting boss 55 when viewed in the direction of the cylinder center axis C1. Since it is formed as the side recess 62, the tool space of the stud bolt 70 and the nut 71 arranged in the outer bolt mounting boss 55 can be formed also in the head cover 6, and the maintenance can be further improved.
内側ボルト取付けボス部51である第一内側ボルト取付けボス部52の座面52aに潤滑油排出用の切欠き部52cが形成されているため、複数のボルト取付けボス部50の内の一部を動弁機構収容室32の外に配置しても、動弁機構80への潤滑油の供給を確実に行うことができる。
Since a notch 52c for lubricating oil discharge is formed in the bearing surface 52a of the first inner bolt mounting boss 52 which is the inner bolt mounting boss 51, a part of the plurality of bolt mounting bosses 50 is Even if disposed outside the valve operating mechanism accommodation chamber 32, the lubricating oil can be reliably supplied to the valve operating mechanism 80.
シリンダヘッド3の第一外側ボルト取付けボス部56と第二外側ボルト取付けボス部57との間には、点火栓39を挿通支持する点火栓孔59aが形成される点火栓取付けボス部59が形成されている。そのため、点火栓取付けボス部59と外側ボルト取付けボス部55を一体に小さく形成してシリンダヘッド3の小型化および軽量化が図れるとともに、点火栓取付けボス部59と外側ボルト取付けボス部55の熱容量を小さくして点火栓39の冷却効果を向上させることができる。
Between the first outer bolt mounting boss portion 56 and the second outer bolt mounting boss portion 57 of the cylinder head 3, an ignition plug mounting boss portion 59 is formed in which an ignition plug hole 59a for inserting and supporting the ignition plug 39 is formed. It is done. Therefore, the spark plug mounting boss portion 59 and the outer bolt mounting boss portion 55 are integrally formed small to achieve downsizing and weight reduction of the cylinder head 3, and the heat capacity of the spark plug mounting boss portion 59 and the outer bolt mounting boss portion 55. Can be reduced to improve the cooling effect of the spark plug 39.
以上、本発明の実施の形態について図面を参照して説明したが、実施の形態は上記の説明の内容に限られず、本発明の趣旨を逸脱しない範囲で変更することができる。
例えば、伝達機構90は、カムチェーンスプロケット機構に限定されず、カムチェーン93の代わりに複数のギアを用いたいわゆるカムギア機構としても良い。
また、ヘッド側凹部35およびカバー側凹部62は、シリンダヘッド3の右側壁30Rに二か所形成されているが、一つの凹部として形成しても良い。 As mentioned above, although embodiment of this invention was described with reference to drawings, embodiment is not restricted to the content of said description, It can change in the range which does not deviate from the meaning of this invention.
For example, thetransmission mechanism 90 is not limited to the cam chain sprocket mechanism, and may be a so-called cam gear mechanism using a plurality of gears instead of the cam chain 93.
Moreover, although the head side recessedpart 35 and the cover side recessed part 62 are formed in two places on the right side wall 30R of the cylinder head 3, you may form as one recessed part.
例えば、伝達機構90は、カムチェーンスプロケット機構に限定されず、カムチェーン93の代わりに複数のギアを用いたいわゆるカムギア機構としても良い。
また、ヘッド側凹部35およびカバー側凹部62は、シリンダヘッド3の右側壁30Rに二か所形成されているが、一つの凹部として形成しても良い。 As mentioned above, although embodiment of this invention was described with reference to drawings, embodiment is not restricted to the content of said description, It can change in the range which does not deviate from the meaning of this invention.
For example, the
Moreover, although the head side recessed
E…内燃機関、1…クランクケース、2…シリンダブロック、3…シリンダヘッド、3a…外壁面、6…ヘッドカバー、21…シリンダボア、30…外周壁、32…動弁機構収容室、37…冷却フィン、39…点火栓、40…吸気ポート、41b…天井壁、41c…吸気ポート壁露出部(外壁面)、42…排気ポート、43b…天井壁、43c…排気ポート壁露出部(外壁面)、50…ボルト取付けボス部、51…内側ボルト取付けボス部、55…外側ボルト取付けボス部、52a…座面、52b…切欠き部、56a…座面、57a…座面、59a…点火栓孔、61…外周壁、70…スタッドボルト、71…ナット(締結部材)、80…動弁機構、81…吸気弁、82…排気弁、84…カムシャフト、90…伝達機構、C1…シリンダ中心軸線
E: Internal combustion engine 1: Crankcase 2: Cylinder block 3: Cylinder head 3a Outer wall surface 6: Head cover 21: Cylinder cover 30: Outer peripheral wall 32: Valve mechanism storage chamber 37: Cooling fin , 39: spark plug, 40: intake port, 41b: ceiling wall, 41c: intake port wall exposed portion (outer wall surface), 42: exhaust port, 43b: ceiling wall, 43c: exhaust port wall exposed portion (outer wall surface), 50: bolt mounting boss, 51: inner bolt mounting boss, 55: outer bolt mounting boss, 52a: seating surface, 52b: cutout, 56a: seating surface, 57a: seating surface, 59a: spark plug hole, DESCRIPTION OF SYMBOLS 61 ... Outer peripheral wall, 70 ... Stud bolt, 71 ... Nut (fastening member), 80 ... Valve-operated mechanism, 81 ... Intake valve, 82 ... Exhaust valve, 84 ... Camshaft, 90 ... Transmission mechanism, C1 ... Cylinder center axis line
Claims (9)
- クランクケース(1)と、内部にシリンダボア(21)を有するシリンダブロック(2)と、動弁機構(80)を収容する動弁機構収容室(32)を形成する外周壁(30)を有し、その外壁面(3a)に複数の冷却フィン(37)が形成されるシリンダヘッド(3)とを具備し、
前記クランクケース(10)に、前記シリンダブロック(2)と前記シリンダヘッド(3)とが順次重ねられ複数のスタッドボルト(70)および該スタッドボルト(70)に取付けられる複数の締結部材(71)により一体に締結され、
複数の前記スタッドボルト(70)は、前記シリンダボア(21)の中心線を通るシリンダ中心軸線(C1)方向視で、前記シリンダボア(21)を周方向に囲むように配置され、
前記シリンダヘッド(3)には、複数の前記スタッドボルト(70)がそれぞれ貫通する複数のボルト取付けボス部(50)が形成され、
複数の前記ボルト取付けボス部(50)は、前記シリンダヘッド(3)の前記動弁機構収容室(32)の内側に配置される内側ボルト取付けボス部(51)と、前記シリンダヘッド(3)の前記動弁機構収容室(32)の外側に配置される外側ボルト取付けボス部(55)とからなる内燃機関(E)において、
前記シリンダヘッド(3)の前記外周壁(30)は、前記シリンダ中心軸線(C1)方向視で、該外周壁(30)の一部が前記外側ボルト取付けボス部(55)の前記締結部材(71)の座面(56a,57a)を避けるように内側へ向けて凹んで形成された凹部(35)を有することを特徴とする内燃機関(E)。 It has a crankcase (1), a cylinder block (2) having a cylinder bore (21) inside, and an outer peripheral wall (30) which forms a valve operating mechanism accommodating chamber (32) for accommodating the valve operating mechanism (80). A cylinder head (3) having a plurality of cooling fins (37) formed on the outer wall surface (3a),
The cylinder block (2) and the cylinder head (3) are sequentially stacked on the crankcase (10) and a plurality of stud bolts (70) and a plurality of fastening members (71) attached to the stud bolts (70) Are united by
The plurality of stud bolts (70) are disposed so as to circumferentially surround the cylinder bore (21) in a direction of a cylinder center axis (C1) passing through the center line of the cylinder bore (21).
The cylinder head (3) is formed with a plurality of bolt mounting bosses (50) through which the plurality of stud bolts (70) respectively penetrate.
A plurality of bolt mounting bosses (50), an inner bolt mounting boss (51) disposed inside the valve mechanism storage chamber (32) of the cylinder head (3); and the cylinder head (3) In an internal combustion engine (E) comprising an outer bolt mounting boss (55) disposed outside the valve operating mechanism housing (32) of
A part of the outer peripheral wall (30) of the outer peripheral wall (30) of the cylinder head (3) is the fastening member (the outer bolt mounting boss (55)) as viewed in the direction of the cylinder center axis (C1). 71) An internal combustion engine (E) characterized in that it has a recess (35) recessed inwardly so as to avoid the bearing surface (56a, 57a) of the 71). - 前記外側取付けボス部(55)の前記座面(56a,57a)は、側面視で、複数の前記冷却フィン(37)の内、少なくとも一部の冷却フィン(37)よりも前記シリンダブロック(2)寄りに位置し、
複数の前記冷却フィン(37)は、前記シリンダ中心軸線(C1)方向視で、前記座面(56a,57a)と重なる領域を避けて形成されることを特徴とする請求項1に記載の内燃機関(E)。 The bearing surface (56a, 57a) of the outer mounting boss portion (55) has the cylinder block (2) more than the cooling fins (37) of the plurality of cooling fins (37) in a side view. ) Located closer to
The internal combustion engine according to claim 1, wherein the plurality of cooling fins (37) are formed avoiding an area overlapping with the seat surface (56a, 57a) in the direction of the cylinder center axis (C1). Organization (E). - 前記内燃機関(1)は、前記動弁機構収容室(32)にカムシャフト(84)が配置されるOHC型内燃機関(1)であり、
前記カムシャフト(84)に駆動力を伝達する伝達機構(90)を備え、該伝達機構(90)が、前記シリンダ中心軸線(C1)方向視で、前記外側ボルト取付けボス部(55)とは前記シリンダボア(21)を挟んで反対側に配置されることを特徴とする請求項1または請求項2に記載の内燃機関(E)。 The internal combustion engine (1) is an OHC type internal combustion engine (1) in which a camshaft (84) is disposed in the valve operating mechanism accommodation chamber (32),
The transmission mechanism (90) for transmitting the driving force to the cam shaft (84), the transmission mechanism (90) being the outer bolt mounting boss (55) in the direction of the cylinder center axis (C1) An internal combustion engine (E) according to claim 1 or claim 2, characterized in that it is arranged on the opposite side across the cylinder bore (21). - 前記シリンダヘッド(3)には、吸気ポート(40)と排気ポート(42)とが設けられ、
前記外側取付けボス部(55)の前記座面(56a,57a)は、側面視で、前記吸気ポート(40)および前記排気ポート(42)の天井壁(41b,43b)よりも前記シリンダブロック(2)寄りに位置することを特徴とする請求項2または請求項3のいずれかに記載の内燃機関(E)。 The cylinder head (3) is provided with an intake port (40) and an exhaust port (42).
The bearing surface (56a, 57a) of the outer mounting boss portion (55) is the cylinder block (side surface) as compared to the ceiling wall (41b, 43b) of the intake port (40) and the exhaust port (42). 2) The internal combustion engine (E) according to any of claims 2 or 3, characterized in that it is located closer. - 前記冷却フィン(37)は、前記吸気ポート(40)および前記排気ポート(42)の外壁面(41c,43c)にも形成されることを特徴とする請求項4に記載の内燃機関(E)。 The internal combustion engine (E) according to claim 4, characterized in that the cooling fin (37) is also formed on the outer wall surface (41c, 43c) of the intake port (40) and the exhaust port (42). .
- 前記動弁機構(80)は、一つの吸気弁(81)および一つの排気弁(82)を備えることを特徴とする請求項1ないし請求項5のいずれか1項に記載の内燃機関(E)。 The internal combustion engine (E according to any one of the preceding claims, characterized in that the valve operating mechanism (80) comprises one intake valve (81) and one exhaust valve (82). ).
- 前記シリンダヘッド(3)には、前記動弁機構収容室(32)を覆うヘッドカバー(6)が取付けられ、
該ヘッドカバー(6)は外周壁(61)を有し、該外周壁(61)は、前記シリンダ中心軸線(C1)方向視で、該外周壁(61)の一部が前記外側ボルト取付けボス部(55)の前記座面(56a,57a)を避けるように内側へ向けて凹んで形成された凹部(62)を有することを特徴とする請求項1ないし請求項6のいずれか1項に記載の内燃機関(E)。 A head cover (6) covering the valve operating mechanism accommodation chamber (32) is attached to the cylinder head (3),
The head cover (6) has an outer peripheral wall (61), and the outer peripheral wall (61) is a part of the outer peripheral wall (61) viewed from the direction of the cylinder center axis (C1). A concave portion (62) formed inward so as to avoid the seating surface (56a, 57a) of (55) according to any one of claims 1 to 6, characterized in that Internal combustion engine (E). - 前記内側ボルト取付けボス部(51)の前記締結部材(71)の座面(52a,53a)の内、少なくとも一つの座面(53a)には、潤滑油排出用の切欠き部(53c)が設けられることを特徴とする請求項1ないし請求項7のいずれか1項に記載の内燃機関(E)。 In at least one seat surface (53a) of the seat surfaces (52a, 53a) of the fastening member (71) of the inner bolt mounting boss (51), a cutout (53c) for lubricating oil discharge is provided Internal combustion engine (E) according to any one of the preceding claims, characterized in that it is provided.
- 前記シリンダヘッド(3)には、点火栓(39)を挿通支持する点火栓孔(59a)が形成され、 該点火栓孔(59a)は、複数の前記外側ボルト取付けボス部(55)の内、一対の外側ボルト取付けボス部(56,57)の間に位置することを特徴とする請求項1ないし請求項8のいずれか1項に記載の内燃機関(E)。 A spark plug hole (59a) for inserting and supporting a spark plug (39) is formed in the cylinder head (3), and the spark plug hole (59a) is formed in the plurality of outer bolt mounting bosses (55). An internal combustion engine (E) according to any of the preceding claims, characterized in that it is located between a pair of outer bolt mounting bosses (56, 57).
Applications Claiming Priority (2)
Application Number | Priority Date | Filing Date | Title |
---|---|---|---|
JP2014-225901 | 2014-11-06 | ||
JP2014225901A JP2018017120A (en) | 2014-11-06 | 2014-11-06 | Internal combustion engine |
Publications (1)
Publication Number | Publication Date |
---|---|
WO2016072385A1 true WO2016072385A1 (en) | 2016-05-12 |
Family
ID=55909110
Family Applications (1)
Application Number | Title | Priority Date | Filing Date |
---|---|---|---|
PCT/JP2015/080918 WO2016072385A1 (en) | 2014-11-06 | 2015-11-02 | Internal combustion engine |
Country Status (2)
Country | Link |
---|---|
JP (1) | JP2018017120A (en) |
WO (1) | WO2016072385A1 (en) |
Citations (6)
Publication number | Priority date | Publication date | Assignee | Title |
---|---|---|---|---|
JPS545115A (en) * | 1977-06-07 | 1979-01-16 | List Hans | Cylinder head for airrcooled internal combustion engine |
JPS59189993U (en) * | 1983-06-03 | 1984-12-17 | マツダ株式会社 | engine superstructure |
JPH0255814A (en) * | 1988-08-19 | 1990-02-26 | Yamaha Motor Co Ltd | One-overhead cam shaft engine |
JPH0763029A (en) * | 1993-08-30 | 1995-03-07 | Nissan Motor Co Ltd | Cam lubricating device for internal combustion engine |
JP2000337211A (en) * | 1999-05-26 | 2000-12-05 | Fuji Heavy Ind Ltd | Engine |
JP2007321692A (en) * | 2006-06-02 | 2007-12-13 | Honda Motor Co Ltd | Cooling structure for internal combustion engine |
-
2014
- 2014-11-06 JP JP2014225901A patent/JP2018017120A/en active Pending
-
2015
- 2015-11-02 WO PCT/JP2015/080918 patent/WO2016072385A1/en active Application Filing
Patent Citations (6)
Publication number | Priority date | Publication date | Assignee | Title |
---|---|---|---|---|
JPS545115A (en) * | 1977-06-07 | 1979-01-16 | List Hans | Cylinder head for airrcooled internal combustion engine |
JPS59189993U (en) * | 1983-06-03 | 1984-12-17 | マツダ株式会社 | engine superstructure |
JPH0255814A (en) * | 1988-08-19 | 1990-02-26 | Yamaha Motor Co Ltd | One-overhead cam shaft engine |
JPH0763029A (en) * | 1993-08-30 | 1995-03-07 | Nissan Motor Co Ltd | Cam lubricating device for internal combustion engine |
JP2000337211A (en) * | 1999-05-26 | 2000-12-05 | Fuji Heavy Ind Ltd | Engine |
JP2007321692A (en) * | 2006-06-02 | 2007-12-13 | Honda Motor Co Ltd | Cooling structure for internal combustion engine |
Also Published As
Publication number | Publication date |
---|---|
JP2018017120A (en) | 2018-02-01 |
Similar Documents
Publication | Publication Date | Title |
---|---|---|
JP5479965B2 (en) | Spark plug cooling device for vehicle engine | |
EP0945598A2 (en) | Four stroke internal combustion engine | |
WO2013047878A1 (en) | Opposed-piston engine | |
US8220429B2 (en) | Overhead valve and rocker arm configuration for a small engine | |
JPH0514081B2 (en) | ||
JP4265746B2 (en) | Bolt and internal combustion engine | |
US6953015B2 (en) | Engine | |
JP2000130254A (en) | Vehicular engine | |
WO2016072385A1 (en) | Internal combustion engine | |
CN104251157A (en) | Engine | |
JPS60187706A (en) | O.h.c. type valve gear for four valve type internal-combustion engine | |
WO2019187079A1 (en) | Engine | |
EP1403497B1 (en) | Camshaft bearing structure for over-head camshaft type internal combustion engine | |
JP4191648B2 (en) | engine | |
JP2013113158A (en) | Head cover structure of internal combustion engine | |
JP3272245B2 (en) | Chain cover structure of 4-cycle engine | |
CN104251164B (en) | Engine | |
JPH11166449A (en) | Four-cycle engine | |
JP2017193994A (en) | Opposed piston type engine | |
JP2007023835A (en) | Secondary air feeding device of internal combustion engine | |
JP4792423B2 (en) | Air-cooled V-type engine | |
US10487703B2 (en) | Rotary valve engine system | |
JP2004052708A (en) | Multiple cylinder engine | |
JP2013007275A (en) | Gas-liquid separation structure for engine | |
JP2013096389A (en) | Monoblock engine |
Legal Events
Date | Code | Title | Description |
---|---|---|---|
121 | Ep: the epo has been informed by wipo that ep was designated in this application |
Ref document number: 15856888 Country of ref document: EP Kind code of ref document: A1 |
|
DPE1 | Request for preliminary examination filed after expiration of 19th month from priority date (pct application filed from 20040101) | ||
NENP | Non-entry into the national phase |
Ref country code: DE |
|
122 | Ep: pct application non-entry in european phase |
Ref document number: 15856888 Country of ref document: EP Kind code of ref document: A1 |
|
NENP | Non-entry into the national phase |
Ref country code: JP |