JP4065751B2 - 4-cycle engine oil supply path - Google Patents

Description

[0001]
BACKGROUND OF THE INVENTION
The present invention relates to an oil supply path for a four-cycle engine suitable for a vehicle such as a motorcycle or a four-wheeled vehicle for riding on rough terrain.
[0002]
[Prior art]
A four-cycle engine is usually provided with an oil pump and an oil supply path from the oil pump to each oil supply point. The oil supply points include a crankshaft, a connecting rod, a piston, and a cylinder head. A valve cam mechanism, a transmission gear, a clutch, etc. correspond (for example, refer to patent documents 1).
[0003]
In order to efficiently supply oil from one oil pump to each of the oil supply points distributed in the engine, oil from one side to the other side in the crankshaft direction of the crankcase is provided in the oil supply path. A passage may be provided.
[0004]
Thus, as the structure of the oil passage that communicates one side and the other side in the crankshaft direction of the crankcase as described above, conventionally, an external piping structure in which pipes or tubes are piped outside the engine, or the wall of the crankcase A structure or the like in which an oil passage is directly formed inside is adopted.
[0005]
As an example of the structure in which the oil passage is directly formed in the crankcase wall, as shown in FIG. 12, for example, as viewed in the direction of the crankshaft core O1, the cylinder 201 is placed at a position that does not overlap the clutch 200 on the clutch cover mating surface. There is an engine in which an oil passage 202 is formed above a distant mission, and a transverse oil passage 203 penetrating from the clutch chamber to the mission chamber is formed in the oil passage 202.
[0006]
The applicant of the present patent has investigated patent documents regarding a crankcase crossing type oil passage related to the present invention, but has not found any patent documents that seem to be closely related.
[0007]
[Patent Document 1]
Japanese Utility Model Publication No. 2-48657.
[0008]
[Problems to be solved by the invention]
In the former external piping structure, piping parts such as tubes and joint pipes increase, which increases costs and increases the number of assembly steps.
[0009]
In the crankcase wall inner structure corresponding to FIG. 12, the crankcase becomes larger and the weight also increases.
[0010]
OBJECT OF THE INVENTION
The object of the present invention is to maintain the compactness of the crankcase by forming a transverse oil passage that crosses the crankcase in the direction of the crankshaft axis by effectively utilizing the dead space in the crankcase, and Another object of the present invention is to provide an oil supply path for a four-cycle engine that can ensure the ease of manufacture and assembly.
[0011]
Another object of the present invention is to allow forced cooling of the inner surface of the piston without providing dedicated piping.
[0012]
[Means for Solving the Problems]
In order to solve the above-mentioned problems, the invention according to claim 1 of the present application is directed to a connecting rod locus and a crank web locus as viewed in the direction of the crankshaft axis in an oil supply path of a four-cycle engine that pumps oil to each oiling point in the engine. and while located within a range surrounded by the skirt rear end or skirt front end of the piston bottom dead center, arranged an oil passage tube traversing the crank case and substantially parallel to the crank axis direction, the oil The passage pipe is positioned such that an edge of the oil passage in the oil passage pipe on the side far from the cylinder center line passes through the bore range when viewed in the cylinder center line direction, and the downstream end of the oil passage The part communicates with an oil passage for supplying oil to an oiling point of the engine .
[0013]
According to the above configuration, since the crankcase crossing-type oil passage forming member is arranged by effectively using the dead space in the crankcase, it is possible to prevent the crankcase from being enlarged. Further, the oil passage pipe serves as a reinforcing rib on the left and right side walls of the crankcase, and the rigidity is improved.
[0014]
According to a second aspect of the present invention, in the oil supply path of the four-cycle engine according to the first aspect , an oil ejection outlet is formed on the outer peripheral wall surface of the oil passage pipe .
[0015]
According to the above configuration, the inner surface of the piston can be cooled without forming a pipe or oil passage dedicated to cooling the inner surface of the piston, and the piston cooling effect can be improved at low cost.
[0016]
According to a third aspect of the present invention, in the oil supply path of the four-cycle engine according to the first or second aspect, the oil passage pipe is divided into left and right crankcase members of the crankcase having a left-right split structure, By connecting the crankcase members, the front end surfaces of the left and right oil passage pipe portions are butted together and connected.
According to a fourth aspect of the present invention, there is provided a piston of a connecting rod locus, a crank web locus, and a bottom dead center as viewed in the direction of the crankshaft axis in an oil supply path of a four-cycle engine that pumps oil to each oil supply point in the engine. Is located within the range surrounded by the rear end of the skirt or the front end of the skirt, and crosses the crankcase substantially parallel to the crankshaft direction so as to pass through the bore range when viewed in the cylinder center line direction. A cylindrical oil passage pipe is arranged, and the oil passage pipe is divided into left and right crankcase members of the crankcase having a left-right split structure. The tip surfaces of the parts are butted and connected.
[0017]
According to the said structure, manufacture and assembly | attachment of a crankcase crossing type oil passage pipe are easy.
[0018]
DETAILED DESCRIPTION OF THE INVENTION
1 to 10 show a dry sump type single-cylinder four-cycle engine to which the present invention is applied, which is mounted on, for example, a motorcycle for motocross. One embodiment of the present invention will be described with reference to these drawings. For convenience of explanation, the crankshaft core direction will be described as the left-right direction.
[0019]
[Crank chamber, mission chamber and oil tank chamber]
FIG. 1 is a vertical side view showing the inside of the right half of the crankcase 2 cut along a plane perpendicular to the crankshaft core O1 and including the cylinder center line C. FIG. In FIG. 1, the crankcase 2 is formed with a crank chamber 4 for accommodating the crankshaft 1 at the front, a mission chamber 5 for accommodating a gear-type mission is formed at the rear, and a lower portion of the mission chamber 5 is an oil tank. It is chamber 9.
[0020]
A cylinder 6 is fastened to the upper surface of the crank chamber 4, and a cylinder head and a head cover (rocker arm cover) are fastened to the upper side of the cylinder 6, as is well known, but not shown. 7 is connected to the crankpin 12 of the crankshaft 1 through a piston pin 10 and a connecting rod 11.
[0021]
A partition wall 16 having a constant height is formed integrally with the crankcase 2 between the crank chamber 4 and the transmission chamber 5, and the oil tank chamber 9 is isolated from the crank chamber 4 by the partition wall 16. .
[0022]
The partition wall 16 is formed to be slightly higher than the crankshaft core O 1, extends forward and downward in an arc along the rotation locus of the crank web 17, and extends downward below the rotation locus of the crank web 17. 18, thereby extending the oil tank chamber 9 to a position below the rear half of the crank chamber 4.
[0023]
A bottom wall 20 is formed on the lower side of the crank chamber 4 along the rotation trajectory of the crank web 17, and the bottom wall 20, the partition wall 18, and the lower end wall of the crankcase 2 are used for a scavenging pump. An oil suction chamber 22 is formed. In the rear end portion of the bottom wall 20, a discharge hole 23 is formed that opens rearward and downward in order to discharge the oil in the crank chamber 4 to the oil suction chamber 22.
[0024]
In the mission chamber 5, a transmission input shaft 27 and a transmission output shaft 28 are arranged in parallel at a position above and below the crankshaft core O 1, and are positioned below the crankshaft core O 1. A change drum 30 is disposed between the input shaft 27 and the speed change output shaft 28 in the front-rear direction, and a change shaft 31 connected to the change pedal is disposed below the change drum 30. O2, O3, O4, and O5 indicate a shift input shaft core, a shift output shaft core, a change drum shaft core, and a change shaft core, respectively. Further, O7 at the front end of the crankcase indicates a balancer shaft core.
[0025]
Oil is stored in the oil tank chamber 9 up to the oil level L1 when the engine is operating. The oil level L1 is approximately the height of the crankshaft O1, and the transmission gear group is immersed in the oil. Is maintained at no height.
[0026]
[Crankshaft]
FIG. 2 is a developed sectional view taken along the line II-II in FIG. 1. The crankcase 2 has a left and right split structure, and includes a cylinder center line C and a plane perpendicular to the crankshaft core O1. The crankcase members 2a and 2b are connected to each other.
[0027]
Crankshaft support holes 41 and 42 are respectively formed in the left and right side walls 34 and 35 of the crankcase 2, and main bearings 37 and 38 are fitted into the crankshaft support holes 41 and 42, respectively. , 38 supports the crankshaft 1 on both ends.
[0028]
The right end portion of the crankshaft 1 passes through the right main bearing 38 and protrudes into the right clutch chamber 44. A primary gear (crank gear) 46 for driving the wheel is fixed to the protruding portion from the right side and also used for driving the pump. The chain sprocket 47 is formed integrally with the crankshaft 1.
[0029]
The left end portion of the crankshaft 1 penetrates the left main bearing 37 and protrudes into the left generator chamber 45, and a generator rotor portion 48 is fixed to the tip tapered portion, and between the rotor portion 48 and the left main bearing 37. The cam chain sprocket 50 is integrally formed, and the balancer drive gear 51 is fixed. The cam chain 49 wound around the cam chain sprocket 50 passes through the cam chain tunnel 74 to reach a cylinder head (not shown), and is linked to the sprocket of the cam shaft for driving the valve.
[0030]
An oil passage 52 extending from the right end to the crank pin 12 is formed in the crankshaft 1.
[0031]
[Mission]
The transmission input shaft 27 in the mission chamber 5 is supported at both ends by bearings 55 and 56 fitted in the shaft support holes of the left and right crankcase side walls 34 and 35. A second-speed gear 58, a fourth-speed gear 59, a third-speed gear 60, a fifth-speed gear 61 and a first-speed gear 62 are provided in this order. It meshes with the transmission gear. The right end portion of the transmission input shaft 27 projects into the clutch chamber 44, and a multi-plate friction clutch 65 is mounted on the projecting portion, and the clutch gear 66 of the friction clutch 65 meshes with the primary gear 46 of the crankshaft 1. The clutch gear 66 is integrally formed with a starting gear 67.
[0032]
An oil passage 71 communicating with the leftmost oil chamber 70 is formed in the speed change input shaft 27. The oil passage 71 is, for example, a fitting portion for a 59th gear for fourth speed and a fifth gear 61 and a fitting for a clutch gear 66. It communicates with the department.
[0033]
[Pump structure]
In FIG. 2, the engine includes two oil pumps, a scavenging pump 77 that pumps return oil from each oil supply location to the oil tank chamber side, and a feed pump 78 that pumps the oil to each oil supply location in the engine. Both pumps 77 and 78 are distributed and arranged on both sides in the direction of the crankshaft core O1, that is, on both the left and right sides, and are provided in the crankcase left side wall 34 and the crankcase right side wall 35, respectively. In this embodiment, a scavenging pump 77 is arranged on the crankcase left side wall 34 on the generator arrangement side, and a feed pump 78 is arranged on the crankcase right side wall 35 on the clutch arrangement side.
[0034]
Each of the pumps 77 and 78 is a trochoid pump in which a pair of inner and outer rotors 77b and 78b are rotatably accommodated in mesh with each other in the pump housings 77a and 78a, and each pump housing 77a and 78a is provided on each crankcase side wall. The front end edges of the pump housings 77a and 78a are formed at positions substantially corresponding to the rear ends of the rotation trajectories of the crank webs 17, respectively. That is, the pumps 77 and 78 are outside the range of the rotation trajectory of the crank web 17 and are located immediately thereafter.
[0035]
Pump covers 80 and 81 are fastened to the end surfaces of the pump housings 77a and 78a in the crankshaft direction. The left scavenging pump 77 is a pump having a larger discharge capacity than the right feed pump 78. Therefore, the left-right width (axial width) of the rotor 77b of the scavenging pump 77 is the left-right width of the rotor 78b of the feed pump 78. It is larger than that and is about twice as large. The scavenging pump 77 is located on the speed change input shaft 27 at a position corresponding to the second-speed gear 58 having the second smallest diameter, and the feed pump 78 corresponds to the first-speed gear 62 having the smallest diameter. Therefore, the distance between the pump shaft O6 and the transmission input shaft core O2 does not need to be widened unnecessarily, and the radial compactness can be maintained.
[0036]
The pump shafts 82 and 83 to which the respective rotors 77b and 78b are fixed are positioned immediately after the partition wall 16 in parallel with the crankshaft core O1, and are aligned on the same pump shaft core O6, via the Oldham coupling 91. Linked together.
[0037]
The right feed pump shaft 83 protrudes into the right clutch chamber 44, and a chain sprocket 85 located between the pump cover 81 and the clutch gear 66 is fixed to the protruding portion, and the chain sprocket 85 is connected to the chain 86. Thus, the crankshaft 1 is linked to the chain sprocket 47 for driving the pump of the crankshaft 1.
[0038]
[Clutch room, etc.]
FIG. 3 shows an outer surface (right side surface) of the right crankcase member 2b and shows the inside of the clutch chamber 44, and the feed pump 78 is shown with its pump cover 81 (FIG. 2) removed. The lower end portion of the crankcase 2 is disposed between the lower pipes P of the vehicle frame. The pump shaft core O6 of the feed pump 78 is located almost directly below the speed change input shaft core (clutch shaft core) O2, and is substantially at the same height as the crank shaft core O1, and the housing portion 78a of the feed pump 78 is provided. Is within the range of the friction clutch 65 when viewed in the direction of the crankshaft core O1). That is, it overlaps with the friction clutch 65 when viewed from the side.
[0039]
A suction pipe 123 is connected to the suction port 122 of the feed pump 78 as shown by an imaginary line in FIG. 1 and extends rearward and downward in the mission chamber 5 to reach the lower end of the oil tank chamber 9. 123 has a built-in secondary filter.
[0040]
In FIG. 3, a discharge-side oil passage 89 extending downward and forward is communicated with the lower end discharge port 129 of the feed pump 78. The discharge-side oil passage 89 is connected to the crankcase right side wall 35 and the pump cover 81 (FIG. 2). It is formed by. A relief oil passage 90 is branched in the middle of the discharge-side oil passage 89, and the relief oil passage 90 communicates with the inside of the clutch chamber 44 via a relief valve 92 provided in the pump cover 81 (FIG. 2). The relief oil is discharged into the clutch chamber 44.
[0041]
An overflow hole 69 having a constant height H2 from the lower end surface of the clutch chamber is formed at the front portion of the clutch chamber 44 and at a position corresponding to the front-rear direction of the crankshaft core O1 and the balancer shaft core O7. The overflow hole 69 communicates with the bottom surface of the crank chamber 4 as shown in FIG. The oil in the clutch chamber 44 in FIG. 3 is maintained at the oil level L2 by overflowing the oil from the overflow hole 69 to the crank chamber 4. Specifically, the oil level L2 is set to such an extent that the clutch 65 is not immersed. Therefore, when the feed pump 78 and the like are arranged at a position overlapping the clutch 65 as viewed from the side as described above, the pump driving chain sprocket 85 and the crankshaft 1 pump driving chain sprocket of FIG. 47 is located at a height that does not soak in oil in the clutch chamber 44.
[0042]
FIG. 4 is a side view showing a state in which the clutch cover 14 is fastened to the right side surface of the crankcase 2. A large circular window hole corresponding to the outer shape of the clutch is formed in the rear half of the clutch cover 14. A circular inspection cover 93 is detachably fastened to the window hole. A tertiary filter storage recess 94 is formed on the front side of the inspection cover 93, and a water pump housing 95 is integrated with the front side of the tertiary filter storage recess 94. Is formed.
[0043]
[Structure for oil supply and transverse oil passage]
An oil passage 97 communicating with the lower end portion of the feed pump discharge side oil passage 89 is formed at the lower end portion of the clutch cover 14, and the oil passage 97 extends forward and upward and bends substantially vertically upward to accommodate the tertiary filter. It reaches the filter entrance of the recess 94.
[0044]
7 is an enlarged cross-sectional view taken along the line VII-VII of FIG. 4. A tertiary filter 98 is stored in the tertiary filter storage recess 94 and a recess cover 99 is detachably attached. Oil passages 101 and 102 are formed which communicate with the outlet of the tertiary filter 98 and branch up and down.
[0045]
The oil passage 101 extending upward communicates with the oil passage 103 of the clutch cover 14 again, and the oil passage 103 communicates with the oil passage 104 formed in the right side wall 35 of the crankcase.
[0046]
FIG. 8 is an enlarged cross-sectional view taken along the line VIII-VIII of FIG. 4. An oil passage 102 extending downward from the tertiary filter 98 reaches the right end of the crankshaft 1 and includes an oil chamber 105 formed in the right side wall 35 of the crankcase. Via the oil passage 52 in the crankshaft 1.
[0047]
FIG. 9 is a plan view of the crank chamber 4 as viewed from above. The oil passage 104 in the right side wall 35 of the crankcase that communicates with the oil passage 103 of the clutch cover 14 moves the crank chamber 4 left and right (in the direction of the crankshaft axis). The oil passage 111 communicates with an oil passage 111 in a transverse oil passage pipe (oil passage forming member) 110 penetrating through the oil passage.
[0048]
The oil passage pipe 110 extends in parallel with the crankshaft core O1 and passes through the bore 7 of the cylinder 6. The oil passage pipe 110 is divided into left and right sides with the mating surfaces of the left and right crankcase members 2a and 2b as a boundary. ing. That is, the left half of the oil passage pipe 110 is integrally formed with the crankcase left side wall 34, the right half of the oil passage pipe 110 is integrally formed with the crankcase right side wall 35, and the left and right oil passage pipes 110 are connected in a butted state. is doing.
[0049]
FIG. 10 is an enlarged cross-sectional view taken along the line XX of FIG. 9, and an oil jet 112 that opens toward the front upper side is formed in the middle of the right oil passage pipe 110. In FIG. 1, the oil passage pipe 110 is seen from the crankshaft core direction, the trajectory of the crank web 17, the trajectory of the connecting rod 11, and the rear end of the skirt of the piston 8 at the bottom dead center position as shown by the phantom line. It is arranged in a space (range) surrounded by 8a. Further, as indicated by an arrow K, the oil ejection port 112 faces the rear part from the piston pin 10 with respect to the piston 8 at the bottom dead center position, but the piston pin with respect to the piston 8 at the top dead center position. It is formed at an angle toward the front part rather than 10.
[0050]
FIG. 5 is an inner surface (right side) view of the left crankcase member 2a. An oil passage 111 of the oil passage pipe 110 includes an oil passage 120 around the cylinder head extending upward in the crankcase left wall 34, and a rear side. Branches to an oil passage 121 for a mission extending to
[0051]
The oil passage 120 extending upward reaches the cam mechanism for driving the valve through an oil passage in the cylinder 6 and an oil passage in the cylinder head (not shown). The transmission oil passage 121 extending rearward reaches a transmission input shaft oil chamber 70 and a transmission output shaft oil chamber 72 formed in the crankcase left side wall 34.
[0052]
[Structure for oil return]
FIG. 6 shows the outer surface (left side surface) of the left crankcase member 2a and shows the inside of the generator chamber 45, and the scavenging pump 77 is shown with the pump cover 80 (FIG. 2) removed. A suction port 124 is formed at the front lower end of the housing part 77a of the scavenging pump 77, and a suction side oil passage 131 that extends forward and downward is communicated with the suction port 124. The suction side oil passage 131 is connected to the left side of the crankcase. It is formed by the wall 34 and the pump cover 80 (FIG. 2), and communicates with the scavenging suction passage 125 at the lower end of the generator chamber through a plate-like primary filter 132. The suction passage 125 is isolated from the generator chamber 45 and is in a state where the suction pressure of the scavenging pump 77 acts.
[0053]
A discharge hole 126 for discharging oil from the generator chamber 45 is formed in front of the scavenging suction passage 125. The discharge hole 126 and the scavenging suction passage 125 are as shown in FIG. And communicated with the oil suction chamber 22 formed on the lower side of the crank chamber 4.
[0054]
That is, the oil that flows in from the generator chamber side through the discharge hole 126 and the oil that flows in from the crank chamber 4 through the rear end discharge hole 23 gather in the oil suction chamber 22, and are scavenged from the scavenging pump suction passage 125. It is sucked into the pump 77. 6 partially enters the crank chamber 4 of FIG. 5 through the discharge hole 25 and is discharged from the rear end discharge hole 23 of the crank chamber 4 to the oil suction chamber 22 in the same manner as described above. It has come to be.
[0055]
The discharge port 136 of the scavenging pump 77 is formed immediately after the upper end of the partition wall 16 and opens toward the mission chamber 5. An arc-shaped flange 137 is integrally formed on the upper side of the discharge port 136 so that oil is not applied to the transmission gear group.
[0056]
[Action]
[Pump drive]
In FIG. 2, the rotation of the crankshaft 1 is transmitted to the feed pump shaft 83 via the pump drive chain sprocket 47, the chain 86, and the chain sprocket 85 of the crankshaft 1 to drive the feed pump 78.
[0057]
Further, the scavenging pump shaft 82 is directly transmitted from the feed pump shaft 83 to drive the scavenging pump 77.
[0058]
Although both the chain sprockets 47 and 85 are disposed in the clutch chamber 44, they are disposed higher than the oil level L2 of the clutch chamber 44 shown in FIG. 3, so that no power loss due to oil resistance occurs. High power transmission efficiency is maintained.
[0059]
[Flow of oil to each lubrication point]
(1) FIG. 11 is a block diagram simply summarizing the oil circulation in the engine. The oil circulation during engine operation will be described with reference to FIG. The oil sucked into the feed pump 78 from the oil tank chamber 9 through the secondary filter enters the tertiary filter 98 through the oil passage 89 in the right side wall of the crankcase and the oil passage 97 in the clutch cover. In the middle of the oil passage 89, a part of the oil is released to the clutch chamber 44 through the relief oil passage 90 and the relief valve 92.
[0060]
(2) The oil filtered by the tertiary filter 98 is divided into two oil passages 101 and 102, and the oil supplied to one oil passage 102 reaches the crankshaft 1 and lubricates around the crankshaft such as a crankpin. .
[0061]
(3) The oil supplied to the other oil passage 101 reaches the inside of the left side wall of the crankcase through a transverse oil passage 111 that traverses the crank chamber. Part of the oil is ejected toward the piston, forcibly cooling the inner surface of the piston. In this case, in FIG. 1, the oil is ejected from the oil ejection port 112 toward the front upper side (K direction), and the ejected oil is in the second half of the top wall of the piston 8 when the piston 8 is lowered to the bottom dead center. It is sprayed to the part (the rear side of the piston pin), and the latter half part of the piston inner surface is mainly cooled. And as piston 8 raises, a spraying part moves ahead and cools substantially the whole piston inner surface.
[0062]
(4) The oil that has passed through the oil passage 111 and reaches the left side wall of the crankcase is further divided into two oil passages 120 and 121, and the oil supplied to one of the oil passages 121 The shaft 27, the transmission output shaft 28, and the clutch 65 are reached, and the fitting portion of each transmission gear and the clutch 65 are lubricated. The oil supplied to the other oil passage 120 reaches a cam shaft around the cylinder head.
[0063]
[Return of oil from each lubrication point]
(1) The oil used for lubricating the speed change input shaft 27 and the speed change output shaft 28 falls or flows down directly into the lower oil tank chamber 9 via the mission chamber 5. The oil used for lubricating and cooling the clutch 65 falls or flows down into the clutch chamber 44.
[0064]
(2) The oil overflowing from the overflow hole 69 of the clutch chamber 44 flows into the crank chamber 4.
[0065]
(3) The oil used for lubrication around the crankshaft 1 and the oil used for cooling the inner surface of the piston 8 fall or flow down to the bottom surface of the crank chamber 4, and the clutch chamber 44 and the like in the crank chamber 4 From the bottom wall and is discharged from the bottom wall rear end discharge hole 23 to the oil suction chamber 22.
[0066]
(4) Oil used for lubrication around the cylinder head and the camshaft falls or flows down to the generator chamber 45 through the cam chain tunnel 74 and is discharged to the oil suction chamber 22 through the lower end discharge hole 126. However, a part of the oil in the generator chamber 45 is discharged to the oil suction chamber 22 through the discharge hole 25, the crank chamber 4 and the rear end discharge hole 23. Therefore, almost no oil is collected in the generator chamber 45.
[0067]
(5) As described above, the return oil from the periphery of the cylinder head, the camshaft, the crankshaft 1 and the piston 8 is collected in the oil suction chamber 22, and the primary filter 132 and the suction side oil passage 131 are passed through the scavenging suction passage 125. Then, it is sucked into the scavenging pump 77, discharged from the discharge port 136 to the mission chamber 5, and returned to the oil tank chamber 9.
[0068]
[Other Embodiments]
(1) In the above embodiment, the jet port 112 of the transverse oil passage 111 is formed only at one place, but it can be formed at a plurality of places. In this case, the inclination angle with respect to the horizontal is different. By doing so, it is possible to spray oil over a wide range to the piston.
[0069]
(2) In the above embodiment, the transverse oil passage pipe is disposed at the rear end of the skirt 8a of the piston 8 at the bottom dead center position on the rear side of the locus of the connecting rod and the locus of the crank web in FIG. 1 is the front side of the trajectory of the connecting rod 11 and the trajectory of the crank web 17 in FIG. 1 and is surrounded by the skirt front end portion 8b of the piston 8 at the bottom dead center position. ).
[0070]
(3) The transverse oil passage pipe may be formed of a pipe member separate from the crankcase.
[0071]
【The invention's effect】
As described above, according to the present invention, (1) as viewed in the direction of the crankshaft axis, the position is within the range surrounded by the connecting rod trajectory, crank web trajectory, and bottom dead center piston skirt rear end or skirt front end. In addition, a cylindrical oil passage pipe that traverses the inside of the crankcase so as to pass through the bore range as viewed in the cylinder center line direction is arranged substantially parallel to the crankshaft axis direction. The dead space can be used effectively for oil passage arrangement, and an increase in the size of the crankcase can be prevented. Also, the oil passage pipe serves as a reinforcing rib on the left and right side walls of the crankcase, and the rigidity of the crankcase is improved.
[0072]
(2) If an oil jet opening that opens toward the lower surface of the top wall of the piston is formed in the middle of the oil passage pipe , the inner surface of the piston can be formed without forming a pipe dedicated to cooling the inner surface of the piston or an oil passage. The cooling effect of the piston can be improved at low cost.
[0073]
(3) The oil passage pipe is divided into left and right crankcase members of a crankcase having a left and right split structure, and the front end surfaces of the left and right oil passage pipe portions are butt-connected by joining the left and right crankcase members. This makes it easy to manufacture and assemble the transverse oil passage.
[Brief description of the drawings]
FIG. 1 is an internal view (left side view) of a right crankcase member of a dry sump type 4-cycle engine to which the present invention is applied.
FIG. 2 is a developed sectional view taken along the line II-II in FIG.
FIG. 3 is an external view (right side view) of a right crankcase member.
FIG. 4 is an external view (right side view) of the right crankcase member showing a state in which a clutch cover is attached.
FIG. 5 is an inner view (right side view) of a left crankcase member.
FIG. 6 is an external view (left side view) of the left crankcase member.
7 is an enlarged sectional view taken along the line VII-VII in FIG.
8 is an enlarged cross-sectional view taken along the line VIII-VIII in FIG.
FIG. 9 is a plan view of the front portion of the crankcase.
10 is an enlarged cross-sectional view taken along the line XX in FIG.
FIG. 11 is a block diagram showing the flow of the entire oil in the engine.
FIG. 12 is an external view of a right crankcase member of a conventional example.
[Explanation of symbols]
1 Crankshaft 2 Crankcase 2a Left crankcase member 2b Right crankcase member 4 Crank chamber 5 Mission chamber 8 Piston 8a Piston rear end 8b Piston front end 9 Oil tank chamber 11 Connecting rod 17 Crank web 110 Transverse oil passage pipe (transverse Type oil passage forming member)
111 Transverse oil passage 112 Spout

Claims (4)

In the oil supply path of a 4-cycle engine that pumps oil to each lubrication point in the engine,
As seen in the crankshaft axis direction, as well as positioned within a range surrounded by the skirt rear end or skirt front end of the piston connecting rod path and the crank web trajectory and the bottom dead center, the crank axis direction in crank case An oil passage pipe that crosses almost in parallel is arranged,
The oil passage pipe is positioned such that an edge of the oil passage in the oil passage pipe on the side far from the cylinder center line passes through the bore range when viewed in the cylinder center line direction.
An oil supply path for a four-cycle engine, characterized in that a downstream end portion of the oil path communicates with an oil path for supplying oil to an oil supply point of the engine. The oil supply path of a four-stroke engine according to claim 1, wherein an oil outlet is formed on an outer peripheral wall surface of the oil passage pipe . The oil passage pipe is divided into left and right crankcase members of the crankcase having a left and right split structure, and the front end surfaces of both the left and right oil passage pipe portions are brought into contact with each other by connecting the left and right crankcase members. The oil supply path of a four-cycle engine according to claim 1 or 2, wherein In the oil supply path of a four-cycle engine that pumps oil to each lubrication point in the engine, the connecting rod trajectory, crank web trajectory, and bottom dead center piston skirt rear end or skirt front end as viewed in the direction of the crankshaft axis. A cylindrical oil passage pipe that is located within the enclosed range and crosses the inside of the crankcase substantially parallel to the crankshaft direction so as to pass through the bore range when viewed in the cylinder center line direction,
  The oil passage pipe is divided into left and right crankcase members of the crankcase having a left / right split structure, and the front end surfaces of the left and right oil passage pipe portions are connected to each other by joining the left and right crankcase members. An oil supply path for a four-cycle engine.

Images