JP2018080691A - Motorcycle - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a motorcycle which is equipped with an internal combustion engine disposed so as to extend a cylinder axis forward, can finely guides oil to a chain guide, and can finely lubricate a chain.SOLUTION: A cylinder head 34 has a center portion 34B which is disposed in the inside of a peripheral wall portion 34A and is attached with an intake valve 46, an exhaust valve 48, and a cam shaft 39. The center portion 34B has an oil gutter 70. The oil gutter 70 is disposed under a center 39c of the cam shaft 39 and on the outer side of an outline of a first sprocket 51 in a vehicle side view, and is formed to be downward toward a chain guide 60. The chain guide 60 has a body portion 61 supporting a cam chain 53, a side part 63 positioned between the body portion 61 and the oil gutter 70, and a guide rib 65 which extends upward to the oil gutter 70 from the side part 63.SELECTED DRAWING: Figure 9

Description

  The present invention relates to a motorcycle.

  Conventionally, a motorcycle including an internal combustion engine having a valve operating device is known. The valve operating apparatus, for example, connects an intake valve and an exhaust valve, a cam that drives the intake valve and the exhaust valve via a rocker arm, a cam shaft provided with the cam, a cam shaft, and a crank shaft of the internal combustion engine. And a chain guide for guiding the cam chain. The valve gear is lubricated by oil.

  Patent Document 1 discloses an internal combustion engine in which a top of a cylinder head cover is disposed above a chain guide, and an oil supply structure in which a rib as a lubricating oil receiving piece is provided on a portion of the cylinder head cover above the chain guide. It is disclosed. The scattered oil is received by the rib and falls from the rib onto the chain guide. Thereby, oil is supplied to the chain guide and the cam chain is lubricated.

  Patent Document 2 discloses an oil supply structure in which a rib is provided in a portion of a cylinder head above an intake valve. The scattered oil is received by the rib and falls to the intake valve. Thereby, the intake valve is lubricated.

Japanese Patent Publication No. 64-3764 Japanese Patent Laying-Open No. 2015-169158

  By the way, an internal combustion engine in which a cylinder axis extends forward is known as an internal combustion engine mounted on a motorcycle. That is, there is known an internal combustion engine in which the angle formed between the cylinder axis and the horizontal line is small in a vehicle side view. In such an internal combustion engine, the cylinder head is disposed in front of the cylinder body, and the cylinder head cover is disposed in front of the cylinder head. The cam chain and the chain guide are arranged so as to extend in the vehicle front-rear direction. In order to lubricate the cam chain and the chain guide satisfactorily, it is effective to supply oil to the vicinity of the end of the chain guide on the opposite side to the traveling direction of the cam chain. This is because the supplied oil is guided together with the cam chain in the traveling direction of the cam chain, so that the entire cam chain and chain guide can be easily lubricated.

  In such an internal combustion engine, the top of the cylinder head cover is disposed in front of the chain guide. Therefore, when the oil supply structure disclosed in Patent Document 1 is adopted, oil cannot be dropped from the rib onto the chain guide. Therefore, the oil supply structure disclosed in Patent Document 1 cannot be adopted. Instead of providing a rib on the top of the cylinder head cover, it is conceivable to provide a rib on a portion of the inner peripheral wall of the cylinder head or the cylinder head cover above the chain guide. However, in that case, there is a sprocket fixed to the camshaft between the rib and the chain guide, so that oil cannot be satisfactorily dropped from the rib onto the chain guide. The oil supply structure disclosed in Patent Document 2 drops oil from the rib to the intake valve, and cannot supply oil to the cam chain and the chain guide.

  The present invention has been made in view of such a point, and an object of the present invention is to provide an internal combustion engine arranged so that a cylinder axis extends forward, and to guide oil well to a chain guide and to improve a cam chain. It is to provide a motorcycle that can be lubricated.

  A motorcycle according to the present invention includes a crankcase in which a crankshaft is housed, a cylinder body connected to the crankcase and having a cylinder formed therein, and connected to the cylinder body, and an intake valve and an exhaust valve are attached to the motorcycle. Cylinder head, a cam shaft rotatably supported by the cylinder head, an intake cam and an exhaust cam provided on the cam shaft and driving the intake valve and the exhaust valve, respectively, and one end of the cam shaft A first sprocket provided on the portion, a second sprocket provided on the crankshaft, a cam chain wound around the first sprocket and the second sprocket, and a chain disposed below the cam chain And a motorcycle arranged in such a manner that the axis of the cylinder extends forward in a side view of the vehicle. A. The cylinder head includes a peripheral wall portion, and a central portion that is disposed inside the peripheral wall portion and to which the intake valve, the exhaust valve, and the cam shaft are attached. The central portion is disposed below the center of the camshaft and outside the outline of the first sprocket in a side view of the vehicle, and has an oil rod that goes downward toward the chain guide. Yes. The chain guide includes a main body portion that supports the cam chain, a side portion that is located on a side of the main body portion, and a guide rib that extends upward from the side portion toward the oil bottle.

  In the motorcycle described above, the center portion of the cylinder head has an oil bottle. The oil that has lubricated the camshaft, intake valve or exhaust valve is guided toward the chain guide by the oil tank. Since the chain guide has a guide rib extending upward toward the oil bottle, the oil falling from the oil bottle is guided to the side part of the chain guide by the guide rib and supplied to the main body. According to the motorcycle described above, since oil is supplied to the chain guide from the center of the cylinder head, the oil is better supplied to the chain guide than when oil is supplied to the chain guide from the rib provided on the peripheral wall of the cylinder head. The cam chain can be lubricated well. Since the oil tank is disposed outside the outline of the first sprocket in a side view of the vehicle, the first sprocket does not get in the way when supplying oil from the oil tank to the chain guide.

  According to a preferred aspect of the present invention, the central portion of the cylinder head has a wall that is disposed between the intake cam, the exhaust cam, and the first sprocket and supports the cam shaft. . The wall is formed with an oil conduction hole connected to the oil tank.

  According to the above aspect, the oil that has lubricated the camshaft, the intake valve, or the exhaust valve flows into the oil tank through the oil communication hole and is guided to the chain guide.

  According to another preferred aspect of the present invention, a vertical gap is formed between the guide rib and the oil bottle.

  According to the above aspect, it is possible to suppress the collision between the guide rib and the oil tank accompanying the vibration of the internal combustion engine. Therefore, deterioration of the guide rib and the oil bottle can be suppressed. In addition, it is possible to suppress the generation of abnormal noise associated with the collision.

  According to another preferred aspect of the present invention, the cylinder head has a vertical rib that protrudes from the tip of the oil tub and extends in the vertical direction.

  According to the above aspect, the oil in the oil bottle is easily dropped through the vertical rib. Therefore, the oil can be supplied more smoothly from the oil bottle to the chain guide.

  According to another preferable aspect of the present invention, the oil tank has a bottom wall and a vertical wall extending upward from the bottom wall. The bottom wall is inclined from the horizontal line so as to go downward as it goes toward the vertical wall in a side view of the vehicle. The vertical rib is provided at the tip of the vertical wall.

  According to the said aspect, oil tends to gather in the direction near a vertical wall among bottom walls. The oil can be concentrated in the oil tank and can be easily dropped through the vertical ribs. Therefore, the oil can be supplied more smoothly from the oil bottle to the chain guide.

  According to another preferred aspect of the present invention, the oil bottle has a bottom wall with a tip portion protruding from the central portion of the cylinder head.

  Since oil is a highly viscous fluid, the oil in the oil cup tends to adhere to the wall surface below the oil cup in the central portion of the cylinder head. However, according to the said aspect, since the front-end | tip part of the bottom wall of an oil bottle protrudes from the center part of a cylinder head, oil tends to fall from an oil bottle. Therefore, the oil can be supplied more smoothly from the oil bottle to the chain guide.

  According to the present invention, there is provided a motorcycle that includes an internal combustion engine arranged such that a cylinder axis extends forward, can guide oil to a chain guide favorably, and can lubricate a cam chain favorably. Can do.

1 is a side view of a motorcycle according to an embodiment of the present invention. It is a vertical sectional view of a power unit. It is the III-III sectional view taken on the line of FIG. It is the figure which looked at the cylinder head from the front along the cylinder axis. It is a perspective view of a cylinder head. It is a perspective view of a chain guide. It is a top view of a chain guide. It is a right view of a chain guide. It is the figure which expanded the vicinity of the guide rib in FIG. FIG. 3 is a sectional view taken along line XX in FIG. 2.

  Hereinafter, a motorcycle according to an embodiment of the present invention will be described with reference to the drawings. As shown in FIG. 1, a motorcycle 1 according to this embodiment is a scooter type motorcycle. The motorcycle 1 includes a body frame (not shown), a front wheel 3, a rear wheel 4, a handle 5, a seat 6, and a power unit 10. The power unit 10 is swingably supported on the body frame by a pivot shaft (not shown).

  In the following description, unless otherwise specified, front, rear, left, right, upper, and lower are virtual seats on the seat 6 when the motorcycle 1 is assumed to be upright on a horizontal plane in an unloaded state. It means front, rear, left, right, top and bottom as seen from a typical rider (not shown). The no-load state refers to a state in which the rider does not get on the motorcycle 1 and is not filled with fuel. Reference numerals F, Rr, L, R, U, and D in the drawings represent front, rear, left, right, upper, and lower, respectively. The front means the front in the vehicle front-rear direction. The rear means the rear in the vehicle front-rear direction.

  Further, unless otherwise specified, the forward direction is not limited to the horizontal forward direction, but includes a direction inclined in a range of −45 ° to + 45 ° with respect to the horizontal forward direction. Similarly, the rear side includes not only a horizontal rearward direction but also a direction inclined in a range of −45 ° to + 45 ° with respect to the horizontal rearward direction. The left side includes not only the left direction of the vehicle width direction but also a direction inclined in a range of −45 ° to + 45 ° with respect to the direction. The right side includes not only the right direction of the vehicle width direction but also a direction inclined in a range of −45 ° to + 45 ° with respect to the direction. The upper direction includes not only a vertically upward direction but also a direction inclined in a range of −45 ° to + 45 ° with respect to the vertically upward direction. The downward direction includes not only the vertically downward direction but also a direction inclined in a range of −45 ° to + 45 ° with respect to the vertically downward direction.

  Unless otherwise specified, the front part of an object refers to a part ahead of the middle of the object in the vehicle longitudinal direction. The rear part of an object refers to a part of the object that is behind the middle in the vehicle longitudinal direction. The upper part of a thing means the part above the middle of the up-and-down direction of the said thing. The lower part of a thing means the part below the intermediate | middle of the up-down direction of the said thing. The left part of an object refers to the left part of the middle of the object in the left-right direction. The right part of an object means a part on the right side of the middle of the object in the left-right direction. The left-right direction has the same meaning as the vehicle width direction.

  FIG. 2 is a vertical sectional view of the power unit 10. 3 is a cross-sectional view taken along line III-III in FIG. As shown in FIG. 2, the power unit 10 is arranged such that the cylinder axis CL extends forward in a vehicle side view. In the vehicle side view, the angle θ formed by the cylinder axis CL and the horizontal line HL is set to 45 degrees or less. Here, the angle θ means an acute angle among the angles formed by the cylinder axis CL and the horizontal line HL in a side view of the vehicle. Thus, in the present embodiment, the angle θ of the power unit 10 is set to be relatively small. The value of θ is not particularly limited, but may be, for example, 0 degrees to 30 degrees, 0 degrees to 15 degrees, or 0 degrees to 10 degrees.

  As shown in FIG. 3, the power unit 10 includes an internal combustion engine 30 and a V-belt type continuously variable transmission 20.

  The continuously variable transmission 20 includes a driving pulley 21, a driven pulley 22, and a V belt 23 wound around the driving pulley 21 and the driven pulley 22. In FIG. 3, the driving pulley 21, the driven pulley 22, and the V belt 23 represent different states in the first half and the second half. The drive pulley 21 is connected to the crankshaft 31 of the internal combustion engine 30. The driven pulley 22 is connected to the axle 4A of the rear wheel 4 via a gear (not shown).

  The internal combustion engine 30 includes a crankcase 32 in which a crankshaft 31 is accommodated, a cylinder body 33 connected to the crankcase 32, a cylinder head 34 connected to the cylinder body 33, and a cylinder head cover connected to the cylinder head 34. 35. The cylinder body 33 is disposed in front of the crankcase 32. The cylinder head 34 is disposed in front of the cylinder body 33. The cylinder head cover 35 is disposed in front of the cylinder head 34.

  The crankshaft 31 extends in the vehicle width direction. A cylinder 36 is formed inside the cylinder body 33. The cylinder 36 may be integrated with the cylinder body 33 or may be a separate body. The cylinder axis CL is a virtual line passing through the center of the cylinder 36. A piston 37 is disposed inside the cylinder 36. The piston 37 and the crankshaft 31 are connected by a connecting rod 38.

  FIG. 4 is a view of the cylinder head 34 as viewed from the front along the cylinder axis CL. FIG. 5 is a perspective view of the cylinder head 34. As shown in FIG. 5, the cylinder head 34 has a peripheral wall portion 34 </ b> A and a central portion 34 </ b> B. The peripheral wall portion 34A is a portion that forms the outer wall of the cylinder head 34, and is a portion that is visible from the outside. The front end surface 34g of the peripheral wall portion 34A is a mating surface corresponding to the rear end surface of the cylinder head cover 35. The cylinder head 34 is connected to the cylinder head cover 35 by aligning the front end face 34g of the peripheral wall portion 34A and the rear end face of the cylinder head cover 35 via a gasket. As shown in FIG. 4, the central portion 34B is a portion arranged inside the peripheral wall portion 34A. When viewed from the direction along the cylinder axis CL, the central portion 34B is separated from the front end surface 34g of the peripheral wall portion 34A.

  As shown in FIG. 5, the central portion 34 </ b> B has a wall 41 and a wall 42. The wall 41 and the wall 42 are aligned in the vehicle width direction. A hole 41 a is formed in the wall 41, and a hole 42 a is formed in the wall 42. A cam shaft 39 (see FIG. 3) passes through these holes 41a and 42a. The cam shaft 39 extends in the vehicle width direction, and is rotatably supported by the wall 41 and the wall 42 via bearings (not shown) (including arbitrary bearings such as a rolling bearing and a sliding bearing). As shown in FIG. 4, the cam shaft 39 is provided with an intake cam 43 and an exhaust cam 44. The intake cam 43 and the exhaust cam 44 are disposed between the wall 41 and the wall 42. A rocker arm 45 is engaged with the intake cam 43, and an intake valve 46 is in contact with the rocker arm 45. The intake cam 43 is configured to drive the intake valve 46 via the rocker arm 45. A rocker arm 47 is engaged with the exhaust cam 44, and an exhaust valve 48 is in contact with the rocker arm 47. The exhaust cam 44 is configured to drive an exhaust valve 48 via a rocker arm 47.

  As shown in FIG. 3, a first sprocket 51 is provided at one end of the cam shaft 39. In the present embodiment, the first sprocket 51 is provided at the right end portion of the cam shaft 39. A second sprocket 52 is provided on the crankshaft 31. An endless cam chain 53 is wound around the first sprocket 51 and the second sprocket 52. The camshaft 39 is connected to the crankshaft 31 via the first sprocket 51, the cam chain 53, and the second sprocket 52. The camshaft 39 is driven by the crankshaft 31 and is configured to rotate.

  As shown in FIG. 4, inside the cylinder head 34, a valve operating chamber 55 in which an intake cam 43, an exhaust cam 44, an intake valve 46, and an exhaust valve 48 are disposed, a first sprocket 51, and a cam chain 53 ( 4 and a cam chain chamber 56 in which a cam chain chamber 56 (not shown in FIG. 2) is disposed is formed. The wall 41 is disposed between the valve operating chamber 55 and the cam chain chamber 56.

  As shown in FIG. 2, a chain guide 57 is disposed above the cam chain 53 and a chain guide 60 is disposed below the cam chain 53 between the cam shaft 39 and the crankshaft 31. The chain guides 57 and 60 are members that guide the traveling of the cam chain 53. The chain guides 57 and 60 are in contact with the cam chain 53. The cam chain 53 slides with respect to the chain guides 57 and 60. A chain tensioner 58 is attached to the cylinder body 33. The chain tensioner 58 applies tension to the cam chain 53 by pressing the chain guide 57 downward.

  Although the length of the chain guide 60 is not particularly limited, the front end 60 a of the chain guide 60 is located in front of the rear end of the first sprocket 51 in the present embodiment. The front end 60 a of the chain guide 60 is located in front of the center 39 c of the cam shaft 39. The rear end 60 b of the chain guide 60 is located behind the front end of the second sprocket 52. The rear end 60 b of the chain guide 60 is located behind the center of the crankshaft 31.

  FIG. 6 is a perspective view of the chain guide 60. FIG. 7 is a plan view of the chain guide 60. FIG. 8 is a right side view of the chain guide 60. The chain guide 60 has a main body portion 61 extending in the vehicle front-rear direction, a left wall portion 62L located on the left side of the main body portion 61, and a right wall portion 62R located on the right side of the main body portion 61. The main body 61 is a portion that supports the cam chain 53. The lateral width of the main body 61 is substantially equal to the lateral width of the cam chain 53. The main body 61 can come into contact with the outer periphery of the cam chain 53. The left wall portion 62L and the right wall portion 62R protrude upward from the main body portion 61. The left wall portion 62L has a function of preventing the cam chain 53 from protruding leftward from the main body portion 61 by contacting the left side portion of the cam chain 53. The right wall portion 62R has a function of preventing the cam chain 53 from protruding rightward from the main body portion 61 by contacting the right side portion of the cam chain 53. In the present embodiment, the material of the chain guide 60 is a synthetic resin. However, the material of the chain guide 60 is not particularly limited.

  As shown in FIG. 7, the chain guide 60 has a side portion 63 located on the left side of the main body portion 61. The side part 63 is provided at the front part of the chain guide 60. In this embodiment, the side part 63 protrudes from the main body part 61 to the left. However, the side part 63 does not necessarily protrude leftward from the main body part 61. For example, the lower portion of the left wall portion 62 </ b> L that extends linearly in the front-rear direction may constitute the side portion 63. In the present embodiment, the portion 62b located on the side portion 63 of the left wall portion 62L is inclined with respect to the vehicle front-rear direction so as to go to the right as it goes rearward. A guide rib 65 extending upward is provided on the side portion 63. The guide rib 65 is formed in a plate shape extending in the vehicle front-rear direction and the vertical direction. Further, the guide rib 65 is formed in a trapezoidal shape whose upper side is shorter than the lower side (see FIG. 8). However, the shape of the guide rib 65 described here is an example, and the shape of the guide rib 65 is not particularly limited. As shown in FIG. 7, the portion of the left wall portion 62 </ b> L that is positioned in front of the guide rib 65 and the guide rib 65 are connected to each other, and no gap is provided between them. On the other hand, the portion 62b located behind the guide rib 65 in the left wall portion 62L and the guide rib 65 are not connected to each other, and a gap is provided between them. However, it is not particularly limited.

  As shown in FIG. 2, the front end portion of the chain guide 60 is a portion that introduces a portion of the cam chain 53 wound around the first sprocket 51 onto the chain guide 60. In order to facilitate the introduction, the front end portion of the chain guide 60 is curved so as to go downward as it goes forward. The rear end portion of the chain guide 60 is a portion that guides the portion of the cam chain 53 that was on the chain guide 60 to the second sprocket 52. The rear end portion of the chain guide 60 is curved downward toward the rear so that the portion of the cam chain 53 smoothly engages with the second sprocket 52.

  FIG. 9 is an enlarged view of the vicinity of the guide rib 65 in FIG. As shown in FIG. 9, an oil rod 70 is formed in a portion of the central portion 34 </ b> B of the cylinder head 34 above the guide rib 65. The oil bottle 70 is inclined with respect to the vehicle width direction so as to go downward as it goes to the right. In other words, the oil bottle 70 is formed in a shape that goes downward as it goes toward the chain guide 60. As shown in FIG. 2, the oil tank 70 is disposed below the center 39 c of the cam shaft 39. Further, the oil tank 70 is disposed outside the outline of the first sprocket 51 in a side view of the vehicle. The oil tank 70 is disposed behind the front end 60a of the chain guide 60 and ahead of the middle of the chain guide 60 in the vehicle front-rear direction in a side view of the vehicle. The oil tank 70 may be disposed within a range of one third of the total length of the chain guide 60 from the front end 60a of the chain guide 60 in a side view of the vehicle, and is disposed within a range of a quarter. It may be arranged within a range of 1/5. When viewed from above, the rear end portion of the first sprocket 51 and at least a part of the oil bottle 70 overlap. At least a part of the oil tank 70 is located in front of the rear end of the first sprocket 51. However, the arrangement of the oil bottle 70 described here is an example, and is not particularly limited.

  As shown in FIG. 9, the guide rib 65 is spaced downward from the oil bottle 70. A gap in the vertical direction is formed between the guide rib 65 and the oil tank 70. However, there may be no vertical gap between the guide rib 65 and the oil tank 70. The upper end portion of the guide rib 65 may be in contact with the oil bottle 70. The oil bottle 70 may have a bottom wall 71 and a vertical wall 72 extending upward from the bottom wall 71. The vertical wall 72 extends upward from the rear end portion of the bottom wall 71. The bottom wall 71 is inclined from the horizontal line so as to go downward as it goes toward the vertical wall 72 in a side view of the vehicle. The tip 71a of the bottom wall 71 protrudes from the central part 34B of the cylinder head 34. A recessed portion 34 b that is recessed in a direction away from the guide rib 65 is formed below the distal end portion 71 a of the bottom wall 71.

  A vertical rib 73 is provided at the tip of the oil bottle 70. The vertical rib 73 protrudes from the tip of the oil bottle 70 and extends in the vertical direction. The vertical rib 73 is disposed outside the outline of the first sprocket 51 in the vehicle side view. The vertical rib 73 is disposed above the guide rib 65. As shown in FIG. 10, the vertical rib 73 is disposed at a position overlapping the guide rib 65 in plan view. In the present embodiment, the vertical rib 73 is provided at the tip of the vertical wall 72. However, the position of the vertical rib 73 is not particularly limited. It is also possible to provide the vertical rib 73 on the bottom wall 71. As shown in FIG. 9, in the present embodiment, the position of the lower end of the vertical rib 73 is higher than the position of the upper end of the guide rib 65. A vertical gap is formed between the vertical rib 73 and the guide rib 65. However, a gap may not be formed between the vertical rib 73 and the guide rib 65.

  As shown in FIG. 10, the tip 71a of the bottom wall 71 has a parallel side 71b parallel to the chain guide 60 in a plan view, and an inclined side 71c inclined from the parallel side 71b. The inclined side 71c extends to the left as it goes forward. The parallel side 71b is disposed between the vertical wall 72 and the inclined side 71c. In plan view, at least a part of the parallel side 71 b overlaps with the guide rib 65.

  As shown in FIG. 3, the cam shaft 39 is formed with an oil passage 75 through which oil flows. The oil in the oil passage 75 flows out of the cam shaft 39, for example, a sliding portion between the cam shaft 39 and the bearing, a contact portion between the intake cam 43 and the rocker arm 45, and a contact between the exhaust cam 44 and the rocker arm 47. It is supplied to a lubricated portion such as a contact portion, a contact portion between the rocker arm 45 and the intake valve 46, and a contact portion between the rocker arm 47 and the exhaust valve 48. After the oil is supplied to the lubricated portion, the oil falls from the lubricated portion to a portion 76 (see FIGS. 5 and 10) in the valve operating chamber 55 in the central portion 34B of the cylinder head 34.

  As shown in FIGS. 5 and 10, the wall 41 is formed with an oil communication hole 77 that communicates the portion 76 and the oil tank 70. As described above, the wall 41 is disposed between the valve operating chamber 55 and the cam chain chamber 56. However, since an oil communication hole 77 connected to the oil bottle 70 is formed in the wall 41, oil that has dropped from the lubricated part to the part 76 passes through the oil communication hole 77 as shown by an arrow A1 in FIG. It is supplied to the oil tank 70.

  The oil in the oil tank 70 flows to the right. That is, the oil in the oil tank 70 flows toward the chain guide 60. And the oil of the oil bottle 70 falls from the front-end | tip part 71a. Although the oil is a highly viscous fluid, since the guide rib 65 is disposed below the oil bottle 70 as shown in FIG. 9, the oil smoothly travels along the surface of the guide rib 65 by contacting the guide rib 65. Fall into. By guiding the oil to the guide rib 65 in this way, the oil is smoothly guided from the oil rod 70 to the chain guide 60, and a sufficient amount of oil is supplied to the chain guide 60 and the cam chain 53.

  As described above, in the motorcycle 1 according to this embodiment, the central portion 34B of the cylinder head 34 has the oil rod 70. The oil that has lubricated the camshaft 39, the intake valve 46, the exhaust valve 48, etc. is guided toward the chain guide 60 by the oil tank 70. Since the chain guide 60 has the guide rib 65 extending upward toward the oil bottle 70, the oil falling from the oil bottle 70 is guided to the side portion 63 of the chain guide 60 by the guide rib 65 and supplied to the main body 61. Is done. According to the motorcycle 1 according to the present embodiment, oil is supplied to the chain guide 60 from the central portion 34B of the cylinder head 34, so that oil is supplied to the chain guide 60 from the rib provided on the peripheral wall portion 34A of the cylinder head 34. Compared to the case, oil can be guided well to the chain guide 60, and the cam chain 53 can be lubricated well.

  As shown in FIG. 2, since the oil rod 70 is disposed outside the contour of the first sprocket 51 in a side view of the vehicle, the first sprocket is supplied when oil is supplied from the oil rod 70 to the chain guide 60. 51 does not get in the way.

  Further, as shown in FIG. 7, the guide rib 65 is provided not on the main body portion 61 but on the side portion 63 of the chain guide 60. In this embodiment, the side part 63 protrudes from the main body part 61 to the left. Therefore, when the cam chain 53 is wound around the first sprocket 51 and the second sprocket 52 when the power unit 10 is assembled, the guide rib 65 does not get in the way. Therefore, it is possible to satisfactorily lubricate the cam chain 53 while avoiding difficulty in assembling the cam chain 53. However, as described above, the side portion 63 does not necessarily protrude sideways from the main body portion 61.

  According to this embodiment, the wall 41 that supports the cam shaft 39 is disposed between the valve operating chamber 55 and the cam chain chamber 56, but the wall 41 is formed with an oil communication hole 77 that is connected to the oil rod 70. Has been. Therefore, as shown in FIG. 10, the oil that has lubricated the camshaft 39, the intake valve 46, the exhaust valve 48, or the like flows into the oil rod 70 through the oil communication hole 77 and is guided to the chain guide 60. Therefore, the cam chain 53 can be lubricated satisfactorily.

  According to the present embodiment, as shown in FIG. 9, a vertical gap is formed between the guide rib 65 and the oil tank 70. As a result, the collision between the guide rib 65 and the oil rod 70 due to the vibration of the internal combustion engine 30 can be suppressed. Therefore, deterioration of the guide rib 65 and the oil bottle 70 can be suppressed. In addition, it is possible to suppress the generation of abnormal noise associated with the collision.

  According to the present embodiment, the vertical rib 73 is provided at the tip of the oil bottle 70. As a result, the oil in the oil bottle 70 is likely to fall through the vertical ribs 73. Therefore, the oil can be smoothly supplied from the oil bottle 70 to the chain guide 60.

  According to the present embodiment, the bottom wall 71 is inclined from the horizontal line so as to go downward as it goes toward the vertical wall 72 in a vehicle side view. Oil tends to gather on the bottom wall 71 closer to the vertical wall 72. Therefore, the oil can be concentrated in the oil bottle 70. Further, according to the present embodiment, the vertical rib 73 is provided at the tip of the vertical wall 72. Therefore, the oil concentrated by the oil bottle 70 can be guided to the chain guide 60 by the vertical rib 73. Therefore, the oil can be smoothly supplied from the oil tank 70 to the chain guide 60.

  By the way, since oil is a highly viscous fluid, the oil in the oil bottle 70 tends to adhere to the wall surface below the oil bottle 70 in the central portion 34B of the cylinder head 34. However, according to the present embodiment, the front end portion 71 a of the bottom wall 71 of the oil bottle 70 protrudes from the central portion 34 </ b> B of the cylinder head 34. Therefore, the oil tends to fall from the oil bottle 70. Therefore, the oil can be smoothly supplied from the oil tank 70 to the chain guide 60.

  According to the present embodiment, the tip 71a of the bottom wall 71 has a parallel side 71b parallel to the chain guide 60 in plan view as shown in FIG. The oil can be efficiently supplied from the bottom wall 71 toward the chain guide 60.

  Although one embodiment of the present invention has been described above, the present invention is not limited to the above embodiment, and the present invention can be implemented in various other forms.

  In the above embodiment, the cam chain 53 and the chain guide 60 are arranged on the right side of the cylinder axis CL, but may be arranged on the left side of the cylinder axis CL. In that case, the first sprocket 51 is provided at the left end portion of the cam shaft 39.

  In the above-described embodiment, the internal combustion engine 30 is a single cylinder engine having only one cylinder 36. However, the internal combustion engine 30 may be a multi-cylinder engine including two or more cylinders 36.

  In the embodiment, the motorcycle 1 is a scooter type motorcycle. However, the motorcycle 1 is not limited to a scooter type motorcycle, and may be another type of motorcycle.

  The terms and expressions used herein are used for explanation and are not used for limited interpretation. It should be recognized that any equivalents of the features shown and described herein are not excluded and that various modifications within the claimed scope of the invention are permitted. The present invention can be embodied in many different forms. This disclosure should be regarded as providing embodiments of the principles of the invention. The embodiments are described herein with the understanding that the embodiments are not intended to limit the invention to the preferred embodiments described and / or illustrated herein. It is not limited to the embodiment described here. The present invention also encompasses any embodiment that includes equivalent elements, modifications, deletions, combinations, improvements and / or changes that may be recognized by those skilled in the art based on this disclosure. Claim limitations should be construed broadly based on the terms used in the claims and should not be limited to the embodiments described herein or in the process of this application.

DESCRIPTION OF SYMBOLS 1 Motorcycle 31 Crankshaft 32 Crankcase 33 Cylinder body 34 Cylinder head 34A Circumferential wall part 34B Center part 39 Camshaft 39c Center of camshaft 43 Intake cam 44 Exhaust cam 46 Intake valve 48 Exhaust valve 51 1st sprocket 52 2nd sprocket 53 Cam chain 60 Chain guide 61 Main body 63 Side 65 Guide rib 70 Oil 樋 CL Cylinder axis

Claims (6)

A crankcase housing the crankshaft;
A cylinder body connected to the crankcase and having a cylinder formed therein;
A cylinder head connected to the cylinder body and fitted with an intake valve and an exhaust valve;
A camshaft rotatably supported by the cylinder head;
An intake cam and an exhaust cam provided on the camshaft, respectively, for driving the intake valve and the exhaust valve;
A first sprocket provided at one end of the camshaft;
A second sprocket provided on the crankshaft;
A cam chain wound around the first sprocket and the second sprocket;
A chain guide disposed below the cam chain,
A motorcycle arranged such that an axis of the cylinder extends forward in a side view of the vehicle,
The cylinder head includes a peripheral wall portion, and a central portion that is disposed inside the peripheral wall portion and to which the intake valve, the exhaust valve, and the cam shaft are attached,
The central portion is disposed below the center of the camshaft and outside the contour of the first sprocket in a side view of the vehicle, and has an oil rod that goes downward as it goes toward the chain guide,
The chain guide includes a main body portion that supports the cam chain, a side portion that is located on a side of the main body portion, and a guide rib that extends upward from the side portion toward the oil bottle. Motorcycle. The central portion of the cylinder head is disposed between the intake cam and the exhaust cam and the first sprocket, and has a wall that supports the cam shaft,
The motorcycle according to claim 1, wherein the wall is formed with an oil conduction hole connected to the oil tank.   The motorcycle according to claim 1, wherein a vertical gap is formed between the guide rib and the oil tank.   The motorcycle according to any one of claims 1 to 3, wherein the cylinder head has a vertical rib that protrudes from a tip of the oil tank and extends in a vertical direction. The oil tank has a bottom wall and a vertical wall extending upward from the bottom wall,
The bottom wall is inclined from the horizontal line so as to go downward as it goes toward the vertical wall in a side view of the vehicle,
The motorcycle according to claim 4, wherein the vertical rib is provided at a tip of the vertical wall.   The motorcycle according to any one of claims 1 to 4, wherein the oil tank has a bottom wall with a tip portion protruding from the central portion of the cylinder head.

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