JP2005291052A - Lubrication structure for internal combustion engine - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To achieve compactness of structure of an internal combustion engine by commonly using members, and improving lubricating oil cooling performance in lubricating structure for the internal combustion engine provided with a crankcase, a cylinder, and a cylinder head. <P>SOLUTION: The crankcase includes the cylinder inclined in a horizontal direction, and an oil pan part having an opening part in the cylinder axial direction is formed below the cylinder. The cylinder head is in such structure as to cover the opening part in the oil pan part. In the cylinder head, a cooling fin is provided on an outer surface covering the oil pan part. An oil passage is formed at a cylinder head inner surface part close to the cooling fin. <P>COPYRIGHT: (C)2006,JPO&NCIPI

Description

  The present invention relates to a lubricating structure of an internal combustion engine, and mainly relates to a lubricating structure and a cooling structure.

  In the conventional internal combustion engine, since the cylinder head and the crankcase are distant from each other, it is difficult to reduce the size of the internal combustion engine and improve the cooling performance by sharing the members. In particular, conventionally, in order to cool the lubricating oil, it is necessary to add a cooling device to the outside of the internal combustion engine, which causes a problem that the internal combustion engine becomes large (see, for example, Patent Document 1).

Japanese Patent Publication No. 3-43115.

The present invention intends to reduce the size of the internal combustion engine structure by sharing the members and improve the oil cooling property for lubrication.

  The present invention solves the above problems, and the invention according to claim 1 is a lubrication structure for an internal combustion engine including a crankcase, a cylinder, and a cylinder head, wherein the crankcase is inclined in a horizontal direction. An internal combustion engine lubricating structure characterized in that an oil pan portion having an opening in a cylinder axial direction is formed below the cylinder, and the cylinder head covers the opening of the oil pan portion. It is about.

  According to a second aspect of the present invention, in the lubricating structure for an internal combustion engine according to the first aspect, the cylinder head is provided with a cooling fin on an outer surface covering the oil pan portion, and the cylinder head inner surface portion close to the cooling fin. It is characterized in that an oil passage is formed.

  According to a third aspect of the present invention, in the lubricating structure for an internal combustion engine according to the second aspect, the crankcase has an oil passage formed along a cylinder axis below the cylinder, and the oil passage near the crankshaft. The oil pump provided and the cylinder head part are communicated with each other.

  According to a fourth aspect of the present invention, in the lubricating structure for an internal combustion engine according to the third aspect, the oil pan portion has a cooling air passage formed substantially parallel to the oil passage in the crankcase. It is a feature.

  According to the first aspect of the present invention, the structure can be simplified by using both the members.

  According to the invention of claim 2, the oil cooler can be formed with a simple structure, and the life of the lubricating oil can be extended.

  According to the invention of claim 3, the oil passage can be formed in the vicinity of the cylinder in the periphery of the cylinder, and the oil passage space can be reduced.

  According to the fourth aspect of the invention, the cooling air passage can be formed by effectively utilizing the empty space of the crankcase, so that the cooling effect can be improved and the internal combustion engine can be downsized.

  FIG. 1 is a side view of a motorcycle 1 with a pedal related to one embodiment of the present invention. A body frame 3 having a sheet metal box-shaped cross section extends rearward and obliquely downward from the head pipe 2. A steering shaft 4 is pivotally supported on the head pipe 2, a handle 5 that extends left and right is provided on the steering shaft 4, and a front wheel 7 is pivotally supported on a front fork 6 that extends downward from the steering shaft 4. A pipe seat post 8 is connected to the rear end portion of the vehicle body frame 3 at a pair of lower ends thereof, and a seat 9 is provided at the upper end of the seat post 8.

  An overhead valve type 4-stroke single-cylinder internal combustion engine 10 is mounted and fixed at the lower part of the body frame 3, and a human-powered pedal shaft 11 is rotatably provided in front of the internal combustion engine 10 and at the lower part of the body frame 3. . A power transmission case 12 is fixed to the left side surface of the internal combustion engine 10, and a rear wheel 13 is rotatably supported at the rear end thereof. The vehicle body frame 3, the internal combustion engine 10, and the power transmission case 12 are fixed to each other.

  The power transmission case 12 houses a power transmission mechanism 14 that transmits the power of the internal combustion engine 10 to the rear wheel 13. The pedal transmission force transmission that transmits the pedal depression force to the rear wheel 13 is outside the power transmission case 12. A mechanism 15 is provided. A fuel tank 16, an air cleaner 17, and a carburetor 18 are provided at the lower part of the seat post 8, and a portion between the pair of pipes of the seat post 8 is a place 19 for the helmet. In addition, 26 is a pedal arm and 27 is a pedal.

  FIG. 2 is an external view of the internal combustion engine 10 and the power transmission case 12 in the above embodiment. The external appearance of the internal combustion engine 10 includes a crankcase 20, a cylinder head 21, and a cylinder head cover 22. Since the cylinder 30 is housed in the crankcase 20, it cannot be seen from the outside. On the right side of the crankcase 20, a generator storage portion 23 is integrally provided. A generator cover 24 is provided outside the generator housing 23. A spark plug 25 is visible in the center of the front surface of the cylinder head 21.

  3 is a diagram showing a cross section of the power unit in a substantially horizontal direction from above, FIG. 4 is a diagram showing a longitudinal section of the internal combustion engine as seen from the left side, and FIG. 5 is a view of removing the cylinder head cover of the internal combustion engine. FIG. 6 is a side view showing the power transmission mechanism 14 and the pedal depression force transmission mechanism 15.

  3 and 4, the outer shell of the internal combustion engine 10 includes a crankcase 20, a cylinder head 21, and a cylinder head cover 22. The crankcase 20 houses a cylinder 30 inclined in a substantially horizontal direction, and an oil pan portion 80 having an opening in the cylinder axial direction front is formed below the cylinder 30 so that the cylinder head 21 is connected to the oil pan. It covers the opening of the part 80. The cylinder 30 is fixed to the cylinder head 21 with bolts 31, and the cylinder head 21 is fixed to the crankcase 20 with bolts 28. Accordingly, the cylinder 30 is held in the crankcase 20 in a cantilevered manner substantially in the horizontal direction by the cylinder head 21. In the cylinder head 21, the joint surface to the crankcase and the joint surface to the cylinder are formed on the same plane. A plurality of fins 32 parallel to the cylinder axis are provided on the outer periphery of the cylinder 30.

  3 and 4, a crankshaft 35 is rotatably held by the crankcase 20 via ball bearings 36A and 36B at the rear portion of the crankcase 20. A ball bearing 36B that supports the left end portion of the crankshaft 35 is supported by the crankcase 20 via a power transmission case base end member 40 described later in detail. The crank pin 37 supports the large end portion of the connecting rod 38, and the small end portion of the connecting rod 38 supports the piston 39. The piston 39 is slidable in the cylinder 30. The rear wheel 13 which is a vehicle driving wheel with respect to the crankshaft 35 is located rearward, and the axis of the cylinder 30 extends almost horizontally forward. That is, the rear wheel 13 and the cylinder 30 are positioned in opposite directions.

  4 and 5, a combustion chamber 45 is formed in a portion of the cylinder head 21 facing the piston 39, and an intake valve 46 and an exhaust valve 47 are provided together with the above-described ignition plug 25. In the internal space in front of the top of the cylinder 30 of the cylinder head 21, the shaft end portions of the intake valve 46 and the exhaust valve 47 protrude, and a valve operating mechanism 48 for driving them is housed. The valve mechanism 48 is an overhead valve type. 4 and 5, the valve operating mechanism 48 includes a cam shaft 49 and a rocker arm shaft 52. The cam shaft 49 is provided with an intake cam 50 and an exhaust cam 51. The rocker arm shaft 52 includes an intake air. A rocker arm 53 and an exhaust rocker arm 54 are provided. A driven pulley 55 is provided at the end of the camshaft 49, and a toothed belt 57 is wound around a drive pulley 56 provided on the crankshaft so that the camshaft 49 is rotationally driven by the crankshaft 35. It has become. In FIG. 4, 60 is an intake port, and in FIG. 5, 61 is an exhaust port.

  In FIG. 4, a cylinder head cover 22 is attached to the top of the cylinder head 21 with a bolt 29 and covers the top of the cylinder head 21. A gas-liquid separation chamber 58 of a breather mechanism is formed inside the cylinder head cover 22. Reference numeral 59 denotes a partition wall that constitutes one wall surface of the gas-liquid separation chamber 58 and partitions the valve mechanism 48.

  3 and 4, an oil pump 70 is attached to the base end member 40 of the power transmission case 12 covering the left surface of the crankcase 20 from the inside thereof. The oil pump shaft 71 is provided with a driven gear 72 and meshes with a drive gear 73 provided on the crankshaft 35 so that the oil pump 70 is driven by the crankshaft 35.

  In FIG. 4, an oil pan portion 80 is formed in the lower portion of the crankcase 20, and a strainer 82 is mounted in the strainer mounting groove 81. A suction oil passage 85 and a discharge oil passage 86 are formed by an oil passage forming member 83 and an oil passage cover member 84 at a portion of the cylinder head 21 that covers the oil pan portion 80. A suction pipe 87 is bridged between the suction oil path 85 and the suction port 74 of the oil pump 70, and a discharge pipe 88 is bridged between the discharge oil path 86 and the discharge port 75 of the oil pump 70. Passed. The suction pipe 87 and the discharge pipe 88 are both provided below the cylinder 30 and are disposed along the axis of the cylinder 30. The oil that flows into the oil pan section 80 and passes upward through the strainer 82 is sucked into the oil pump 70 through the oil suction hole 95, the suction oil passage 85, and the suction pipe 87, and is added by the oil pump 70. Compressed and discharged via the discharge pipe 88 and the discharge oil passage 86.

  In FIG. 5, the discharged oil is injected to the valve operating mechanism 48 via oil passages 89, 90, 91, 92, 93, 94 following the discharge oil passage 86. The oil passage is connected from the end of the discharge oil passage 86 to the oil passage 90 provided on the end surface of the crankcase 20 by the wall oil passage 89, and from the end of the oil passage 90 by the wall oil passage 91 to the cylinder head 21. Is connected to an oil passage 92 provided on the end face, and reaches the oil injection hole 94 through the oil passage 93 in the wall. Oil is injected from the oil injection hole 94 to the valve mechanism 48.

  In FIG. 4, the oil pump is provided with an oil pump internal oil passage 76 connected to the discharge port 75 on the joint surface to the power transmission case base end member 40, and an oil injection hole 77 connected to the end of the oil pump. . The pressurized oil is injected from the oil injection hole 77 toward the large end portion of the connecting rod 38, and the sliding portion between the crankshaft 35 is lubricated. The oil injected to the valve operating mechanism 48, the large end of the connecting rod 38, the crankshaft 35, etc. flows down in the cylinder head 21 and the crankcase 20, drops into the oil pan 80, and accumulates again. Inhaled, pressurized and circulated. In addition, a valve mechanism such as a camshaft is provided above the cylinder axis in the cylinder head, and the cylinder head is mounted on the vehicle body so that the rear part is slightly lowered. Can be maintained well.

  In FIG. 5, the internal combustion engine 10 is provided with a cooling air passage 63 extending from the front surface of the cylinder head 21 to the rear surface of the crankcase 20 substantially parallel to the suction pipe 87 and the discharge pipe 88. The cooling air passage 63 is composed of a cylinder head portion 63A and a crankcase portion 63B. A plurality of fins 64 extending in the front-rear direction are provided on the inner surface of the crankcase portion 63B so as to cool the oil scattered or flowing down in the crankcase. 4 and 5, fins 65 are also provided on the front surface of the wall body portion of the cylinder head 21 that covers the oil pan portion 80, and this serves to cool the inside of the crankcase 20 and the oil passage. Further, fins 66 are also provided on the front surface of the cylinder head cover 22 (FIG. 4), which helps cool the oil in the gas-liquid separation chamber 58.

  In FIG. 3, a generator storage section 23 is provided on the right side of the crankcase 20, and a generator 68 is stored therein. The generator 68 is rotationally driven by the end of the crankshaft 35 that protrudes outward from the right side surface of the crankcase 20. The generator housing 23 is covered with a generator cover 24 having a ventilation gap.

  In FIG. 3, the power transmission case 12 is formed by an inner member 41, an outer member 42, and a rear member 43 that are sequentially assembled to the base end member 40. The base end member 40 forms part of the power transmission case 12 and also serves as a lid for the opening of the left wall of the crankcase.

  The motorcycle 1 is provided with five rotating shafts of a pedal shaft 11, a crank shaft 35, a driven shaft 96, an intermediate shaft 97, and a rear axle 98 in order from the front. The pedal shaft 11 is rotatably supported by the vehicle body frame 3. The crankshaft 35 is rotatably supported on the right wall of the crankcase and the base end member 40 of the power transmission case 12 via ball bearings 36A and 36B, respectively. The driven shaft 96, the intermediate shaft 97, and the rear axle 98 are all rotatably supported by the inner member 41 and the rear member 43 of the power transmission case 12. The driven shaft 96 and the rear axle 98 are supported via ball bearings.

  In FIGS. 3 and 6, a crankshaft 35, a driven shaft 96, an intermediate shaft 97, and a rear axle 98 are axes related to power transmission from the internal combustion engine 10 to the rear wheel 13. A drive pulley 100 is provided at the left end of the crankshaft 35, a driven pulley 101 is rotatably provided on the driven shaft 96, and an endless V-belt 102 is bridged between both pulleys to provide a V-belt type continuously variable transmission. A machine 103 is configured. FIG. 6 shows the position of the low gear ratio and the position of the high gear ratio of the V belt 102. A centrifugal clutch 104 provided at the left end of the driven shaft 96 disconnects the system between the driven pulley 101 and the driven shaft 96. The small-diameter gear 105 provided on the driven shaft 96 and the large-diameter gear 106 provided on the intermediate shaft 97 mesh with each other, and the small-diameter gear 107 provided on the intermediate shaft 97 and the rear axle 98 are mounted via the one-way clutch 108. The reduction gear mechanism 110 is configured by meshing with the large-diameter gear 109. The V-belt continuously variable transmission 103 and the reduction gear mechanism 110 constitute a power transmission mechanism 14. The power transmission mechanism 14 is housed in the power transmission case 12. The V belt 102 is a first endless transmission member.

  In FIG. 3, a drive sprocket 112 is attached to the left end portion of the pedal shaft 11. The driver's pedaling force of the pedal 27 is transmitted through the pedal arm 26 and the pedal shaft 11, and the drive sprocket 112 is driven to rotate. A driven sprocket 114 is pivotally supported on the rear axle 98 via a one-way clutch 113. An endless chain 115 is bridged between the two sprockets, and the pedaling force is transmitted to the rear wheel 13 through the endless chain 115. The rotation of the rear wheel 13 is not transmitted to the pedal 27 by the action of the one-way clutch 113. As shown in FIG. 6, tension is applied to the endless chain 115 by the action of the idle pulley 116 and the tensioner pulley 117. The pedal depression force transmission mechanism 15 is configured by the above members. The endless chain 115 of the pedal depression force transmission mechanism 15 is disposed outside the power transmission case 12. The endless chain 115 is a second endless transmission member.

  As shown in FIGS. 4 and 5, the intake valve 46, the exhaust valve 47, the cam shaft 49, the rocker arm shaft 52, etc. of the valve mechanism 48 are shifted upward while avoiding the front in the axial direction of the cylinder 30. is there. As a result, a space opposite to the valve mechanism with respect to the axis of the cylinder head, that is, a space below the valve mechanism is vacated. As can be seen in FIGS. 4 and 6, a pedal shaft 11 is provided in this empty space. As a result, the pedal shaft can be brought closer to the crankshaft.

  7 is a front view of the crankcase 20, FIG. 8 is a right side view of the crankcase 20 (viewed along arrow VIII in FIG. 7), FIG. 9 is a left side view of the crankcase 20 (viewed along arrow IX in FIG. 7), FIG. These are XX sectional drawing of FIG. The crankcase 20 is formed in a bottomed box shape with an open front.

  In FIG. 7, a joining surface 120 with the cylinder head 21 is formed around the front opening, a packing groove 121 is formed on the surface, and a plurality of cylinder head connecting screw holes 122 are provided. The crankcase end face oil passage 90 (FIG. 5) is formed in a part of the connection surface. The upper half of the crankcase 20 is a cylinder storage space 123.

  In FIG. 8, a generator housing 23 is provided on the right side of the crankcase 20, and a crankshaft insertion hole 124 is provided in the center. Fins 67 are integrally formed on the side surface. Bolt insertion holes 125 for attaching the internal combustion engine 10 to the vehicle body are integrally formed in the upper part and the lower part.

  In FIG. 9, a large crankcase left wall opening 126 is provided at the center of the left surface of the crankcase 20. The crankcase left wall opening is a portion covered by the power transmission case base end member 40. The periphery of the opening 126 is the base end member joining surface 127, and a plurality of base end member attaching screw holes 128 are provided in the periphery.

  4 and 7, an oil pan portion 80 having an opening in the cylinder axial direction front is formed below the crankcase 20 and below the cylinder storage space 123. This portion is covered with the cylinder head 21 so that the lubricating oil flowing down inside the crankcase is accumulated. A strainer mounting groove 81 (FIG. 7) is formed in the oil pan portion 80. After the strainer 82 is fitted into the oil pan portion 80, the opening is covered with the cylinder head 21, and the state shown in FIG. A communication hole 80b is provided in an oil pan partition wall 80a at the lower center of the crankcase.

  7 and 10, the crankcase 20 is provided with a crankcase portion 63B of the cooling air passage 63 that is orthogonal to the front opening surface and penetrates from the front portion to the rear portion. This is at a position corresponding to the cylinder head portion 63A of the cooling air passage 63 so that the traveling air can pass while the vehicle is traveling. A plurality of fins 64 are formed on the inner surface of the cooling air passage 63B to improve the cooling effect of the oil that scatters and flows down inside the crankcase.

  11 is a front view of the cylinder head 21, and FIG. 12 is a sectional view taken along line XI-XI in FIG. In FIG. 11, a cylinder head cover joint surface 129 is provided in the upper part, and a plurality of cylinder head cover mounting screw holes 130 are provided in the periphery. The portion of the cylinder head 21 covering the oil pan portion 80 of the crankcase 20 includes the oil suction hole 95, the suction oil passage 85, the inlet 87A to the suction pipe 87, the outlet 88A from the discharge pipe 88, and the discharge oil passage. 86 and a wall oil passage 89 are provided. The cylinder head cover joint surface 129 has a wall oil passage 91 communicating with the wall oil passage 89, a cylinder head end face oil passage 92, a wall oil passage 93, and an oil injection hole 94. A spark plug mounting hole 131 and an exhaust port 61 are provided in the center. A large number of fins 65 are provided on the outer surface of the portion of the lower crankcase covering the oil pan portion, and a cylinder head portion 63A of the cooling air passage is opened therein.

  In FIG. 12, the combustion chamber 45, the spark plug attachment hole 131, and the intake valve attachment portion 132 can be seen in the center. An intake port 60 extends upward from the intake valve mounting portion 132. The peripheral part of the combustion chamber 45 is a joint surface of the cylinder 30, and the upper and lower ends of FIG. 12 are joint surfaces to the crankcase. The joint surface of the cylinder 30 and the joint surface to the crankcase 20 are on the same plane. 133 is a rocker arm shaft support hole.

  FIG. 13 is a longitudinal sectional view of the cylinder 30, and FIG. 14 is a view taken along arrow XIV in FIG. The cylinder 30 is fixed to the cylinder head 21 with bolts 31. A large number of fins 32 are provided on the side surface of the cylinder 30 and are cooled by oil scattered in the crankcase 20.

  FIG. 15 is a plan view of the power transmission case base end member 40 as viewed from the crankcase 20 side. As shown in FIG. 3, the power transmission case base end member 40 constitutes a part of the power transmission case 12, and serves as a lid for the crankcase left wall opening 126 shown in FIG. Reference numeral 136 in FIG. 15 denotes a packing groove at the joint. A crankshaft insertion hole 137 is provided in a portion of the power transmission case base end member 40 serving as a lid of the crankcase left wall opening 126, and supports the crankshaft 35 via a ball bearing 36B shown in FIG. An oil pump mounting portion 138 is provided below the crankshaft insertion hole 137. The oil pump 70 shown in FIGS. 3 and 4 is attached so as to be inside the crankcase 20. The left half of the power transmission case base end member 40 in FIG. 15 is an attachment portion for a member constituting the power transmission case 12, and the power transmission case 12 is assembled by a plurality of bolt insertion holes 139.

As described in detail above, in this embodiment,
(1) The crankcase can accommodate a cylinder that is cantilevered by the cylinder head, and can use the cylinder head as one wall of the oil pan to simplify the structure.
(2) An oil cooler can be formed with a simple structure by providing an oil passage and a cooling fin in the cylinder head, and the life of the lubricating oil can be extended.
(3) Since the oil passage is formed by the pipe, the oil passage can be formed in the vicinity of the cylinder in the vicinity of the cylinder, and the oil passage space can be reduced.
(4) The cooling air passage can be formed by effectively utilizing the empty space in the crankcase, improving the cooling effect of the lubricating oil scattered and flowing down in the crankcase, and reducing the size of the internal combustion engine. it can.

1 is a side view of a motorcycle with a pedal 1 according to an embodiment of the present invention. 2 is an external view of an internal combustion engine 10 and a power transmission case 12 in the embodiment. FIG. It is the figure which looked at the cross section of the substantially horizontal direction of the said power unit from the top. It is the figure which looked at the longitudinal cross-section of the said internal combustion engine from the left side. It is the front view which removed the cylinder head cover of the said internal combustion engine. 2 is a side view showing a power transmission mechanism 14 and a pedal depression force transmission mechanism 15. FIG. 2 is a front view of a crankcase 20. FIG. FIG. 8 is a right side view of the crankcase 20 (viewed along arrow VIII in FIG. 7). FIG. 8 is a left side view of the crankcase 20 (a view taken along arrow IX in FIG. 7). It is XX sectional drawing of FIG. 2 is a front view of a cylinder head 21. FIG. It is XI-XI sectional drawing of FIG. 2 is a longitudinal sectional view of a cylinder 30. FIG. It is a XIV arrow line view of FIG. FIG. 4 is a plan view of a power transmission case base end member 40 as viewed from the crankcase 20 side.

Explanation of symbols

20 ... Crank case, 21 ... Cylinder head, 22 ... Cylinder head cover, 30 ... Cylinder, 63 ... Cooling air passage, 63A ... Cylinder head portion of cooling air passage, 63B ... Crank case portion of cooling air passage, 64 ... Fin (cooling) (In the air passage), 65 ... fins (lower cylinder head), 70 ... oil pump, 80 ... oil pan, 85 ... suction oil passage, 86 ... discharge oil passage, 87 ... suction pipe, 88 ... discharge pipe.

Claims (4)

In a lubricating structure of an internal combustion engine including a crankcase, a cylinder, and a cylinder head,
The crankcase houses a cylinder inclined in the horizontal direction,
An oil pan portion having an opening in the cylinder axial direction is formed below the cylinder,
The lubricating structure for an internal combustion engine, wherein the cylinder head covers an opening of the oil pan portion. The cylinder head is provided with cooling fins on the outer surface covering the oil pan portion,
2. The lubricating structure for an internal combustion engine according to claim 1, wherein an oil passage is formed in an inner surface portion of the cylinder head adjacent to the cooling fin. The crankcase has an oil passage formed along a cylinder axis below the cylinder, and an oil pump provided in the vicinity of the crankshaft and the cylinder head portion communicate with each other by the oil passage. Item 3. A lubricating structure for an internal combustion engine according to Item 2. 4. The lubricating structure for an internal combustion engine according to claim 3, wherein a cooling air passage is formed in the oil pan portion substantially parallel to the oil passage in the crankcase.

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