TWI472677B - Internal combustion engine and motorcycle equipped with the engine - Google Patents

Description

Internal combustion engine and locomotive with it

The present invention relates to an internal combustion engine mounted on a straddle type vehicle such as a locomotive and a locomotive having the same.

As an internal combustion engine mounted in a straddle type vehicle such as a locomotive, it is known that the cylinder is disposed to extend forward or forward obliquely upward. The internal combustion engine includes a cylinder block and a cylinder head that form a combustion chamber, an intake valve and an exhaust valve that open and close an intake port and an exhaust port of the combustion chamber, and a cam shaft that drives the valves. Hereinafter, the intake valve, the exhaust valve, and the components for operating the valves are referred to as "moving valve systems". An example of a camshaft-activated valve system.

Since the dynamic valve system is a movable part, it is necessary to supply oil. Lubrication of the internal combustion engine is performed, for example, using an oil pump disposed in the crankcase. Since the dynamic valve system is disposed inside the cylinder head, it is located away from the oil pump disposed in the crankcase. In order to supply oil to the moving valve system, it is necessary to reach the longer oil supply passage near the moving valve system from the oil pump.

A technique in which a pipe is attached to the outside of a cylinder block and a cylinder head and the pipe is used as a part of an oil supply passage is known. However, if a pipe that is not integrated with the cylinder block or the like is provided, the number of parts is increased, and assembly work becomes troublesome. Therefore, there has been proposed a technique in which a passage is formed inside a wall of a cylinder block or the like, thereby forming an oil supply passage by the passage.

In an internal combustion engine in which the cylinder is disposed to extend forward or obliquely upward, either the intake valve and the exhaust valve are located above the cylinder axis. Hereinafter, the valve above the intake valve and the exhaust valve is referred to as the upper valve, and will be positioned The valve below is called the lower valve. Here, when oil is supplied to the camshaft, the oil is dripped by gravity and is also supplied to the lower valve. Therefore, oil can be supplied even if a dedicated oil supply passage is not provided for the lower valve. However, it is not possible to cause the oil supplied to the camshaft to flow directly against the upper valve. Therefore, there has been proposed a technique of supplying oil to the upper valve from above with the oil supply passage being formed at a position higher than the upper valve.

Such an oil supply passage is disclosed in Japanese Laid-Open Patent Publication No. Hei 9-144520 (hereinafter referred to as Document 1). The oil supply passage disclosed in Document 1 is constituted by a plurality of passages formed in the wall of the cylinder block, the wall of the cylinder head, and the inside of the wall of the cylinder head cover. An opening is formed in an inner surface of the upper wall of the cylinder head cover, and the opening is directly above the valve stem end of the upper valve. The oil ejected from the oil pump is supplied from the above opening to the upper valve through the oil supply passage.

However, in the oil supply passage disclosed in Document 1, there is a restriction that an opening is formed directly above the end of the stem of the upper valve. Due to this limitation, there is a case where the configuration of the oil supply passage is complicated, or the cylinder head or the cylinder head cover is enlarged.

The present invention has been made in view of the above circumstances, and an object of the present invention is to provide an internal combustion engine that can smoothly supply oil to an upper valve even if an opening is formed at a position directly above the upper valve.

The internal combustion engine of the present invention comprises: a casing that houses a crankshaft; a cylinder block, It is formed integrally with or separately from the box body, and extends from the box body toward the front or the front obliquely upward; the cylinder head is fixed to the front end portion of the cylinder block, and divides the combustion chamber together with the cylinder block, and is formed to face An intake port and an exhaust port of the combustion chamber; a head cover fixed to a front end of the cylinder head; a valve disposed inside the head cover and the cylinder head and at least partially disposed above a cylinder axis, and opening and closing the above And an oil pump configured to be driven inside the casing and driven by the crankshaft to change a discharge amount according to a rotational speed of the crankshaft; and an oil supply passage A passage formed in the cylinder block, the cylinder head, and the wall of the head cover is provided, and the oil sprayed from the oil pump is guided. An opening connected to the oil supply passage is formed at a position higher than the valve in the inner surface of the head cover and at a position deviated from a position directly above the valve. The internal combustion engine further includes a first rib projecting from an inner surface of the head cover, one end of which is located laterally of the opening, and the other end of which is located directly above the valve.

According to the present invention, it is possible to provide an internal combustion engine which can smoothly supply oil to the upper valve even if the opening is not formed at a position directly above the upper valve.

Hereinafter, an embodiment of the present invention will be described. In the following description, the front, the rear, the left, and the right respectively refer to the front, rear, left, and right of the locomotive 1 being observed by the rider. The symbols F, Re, L, and R attached to the drawings indicate front, back, left, and right, respectively.

As shown in FIG. 1, a straddle type vehicle equipped with the internal combustion engine of the present embodiment Speed-up locomotive 1. The locomotive 1 includes: a body frame 2; and an engine unit 10 that is swingably supported by the body frame 2 via a pivot 3. The engine unit 10 is a so-called unit rocking engine unit. However, the straddle type vehicle equipped with the internal combustion engine of the present invention may be other types of locomotives, such as a moped type, a motor cycle type locomotive, or the like. Although not shown in the drawings, the engine unit 10 may be an engine unit that is fixed to the chassis that is a part of the body frame without being shaken. Further, the straddle type vehicle of the present invention is not limited to a locomotive, but may be other straddle type vehicles such as an ATV (All Terrain Vehicle).

The side of the body frame 2 is covered by the body cover 4. An air cleaner 29 is disposed above the engine unit 10. The body frame 2 includes a head tube 2A. A front fork 5 is supported on the head pipe 2A. A handle 6 is attached to the upper portion of the front fork 5. A front wheel 7 is supported at the lower end of the front fork 5. The body frame 2 includes a pair of left and right side frames 2B. The side frame 2B extends obliquely upward rearward when viewed from the side. The buffer unit 8 is spanned at the rear of the engine unit 10 and after the side frame 2B. A rear wheel 9 is supported at the rear end of the engine unit 10.

As shown in FIG. 2, the engine unit 10 includes an engine 13 as an example of an internal combustion engine and a V-shaped belt-type continuously variable transmission (hereinafter referred to as CVT (Continuously Variable Transmission)) 20. The engine 13 includes a crankshaft 12 and a crankcase 14 that houses the crankshaft 12. The driving force of the crankshaft 12 is transmitted to the rear wheel 9 via the CVT 20.

The CVT 20 includes a first pulley 21 as a drive side pulley and a second pulley 22 as a driven side pulley. A V-shaped belt 23 is wound around the first pulley 21 and the second pulley 22. The first pulley 21 is attached to the left end of the crankshaft 12. 2nd slip The wheel 22 is mounted on the main shaft 24. The main shaft 24 is connected to the rear wheel shaft 25 via a gear mechanism (not shown). In addition, FIG. 2 shows a state in which the speed ratio is different between the front side portion and the rear side portion of the first pulley 21. The second pulley 22 is also the same. The CVT 20 is housed in the transmission case 30. The transmission case 30 is disposed to the left of the crankcase 14.

As shown in FIG. 3, the engine 13 includes a cylinder block 11 that extends obliquely upward from the crankcase 14 toward the front, a cylinder head 15 that is fixed to the front end of the cylinder block 11, and a head cover 16 that is fixed to the cylinder head 15. Before the end. The cylinder block 11, the cylinder head 15, and the head cover 16 constitute a cylinder.

Symbol L1 denotes the center line of the cylinder block 11, that is, the cylinder axis. The cylinder axis L1 extends obliquely upward toward the front. Further, the orientation of the cylinder axis L1 is not limited to the front oblique upper side, and may be the front direction. The cylinder axis L1 can be either inclined from the horizontal line or parallel to the horizontal line. Here, the inclination angle of the cylinder axis L1 from the horizontal line is about 10 degrees, and the cylinder axis L1 extends substantially horizontally. The smaller the inclination angle of the cylinder axis L1, the more the effect of the present invention can be exhibited. However, the inclination angle of the cylinder axis L1 is not particularly limited, and may be, for example, 15 degrees or less, 30 degrees or less, or 45 degrees or less. .

The piston 17 is slidably accommodated in the cylinder block 11. The piston 17 and the crankshaft 12 are connected via a connecting rod 18. The combustion chamber 19 is divided by the cylinder block 11, the cylinder head 15, and the piston 17.

An intake port 31 and an exhaust port 32 are formed in the cylinder head 15. The intake port 31 and the exhaust port 32 face the combustion chamber 19. The intake port 31 is located above the cylinder axis L1, and the exhaust port 32 is located further below the cylinder axis L1.

A dynamic valve system is disposed inside the cylinder head 15 and the head cover 16. Dynamic valve system The cam shaft 35, the first rocker arm 36, the second rocker arm 37, the intake valve 41, and the exhaust valve 42 are included.

The intake valve 41 is disposed above the exhaust valve 42. The intake valve 41 is disposed above the cylinder axis L1, and the exhaust valve 42 is disposed further below the cylinder axis L1. Therefore, the intake valve 41 may be referred to as an upper valve and the exhaust valve 42 may be referred to as a lower valve. The intake valve 41 and the exhaust valve 42 can use various valves that have been used as intake valves and exhaust valves for internal combustion engines.

The intake valve 41 includes an umbrella portion 41a that is slightly larger than the intake port 31, a rod-shaped valve stem 41b that extends obliquely upward from the umbrella portion 41a, and a retainer 41c that is disposed at the front end of the valve stem 41b. And a spring 41d that energizes the valve stem 41b such that the umbrella portion 41a closes the air inlet 31. The holder 41c is formed to have a larger diameter than the valve stem 41b. The holder 41c supports one end of the spring 41d.

Since the exhaust valve 42 has the same configuration as the intake valve 41, the description thereof will be omitted. However, the exhaust valve 42 is different from the intake valve 41 in that it is disposed such that the valve stem extends obliquely downward toward the front.

The first cam 33 and the second cam 34 are provided on the cam shaft 35. The first cam 33 and the second cam 34 are disposed at positions offset from the axial direction of the cam shaft 35 (the front and rear directions in FIG. 3). As shown in FIG. 6, a sprocket 40a is fixed to the left end of the cam shaft 35. The sprocket 40a is coupled to the crankshaft 12 via a chain 40. The camshaft 35 is driven by the crankshaft 12 and rotates with the crankshaft 12.

The first rocker arm 36 is rotatable about the shaft 36a (see FIG. 3). As shown in FIG. 3, one end of the first rocker arm 36 is in contact with the first cam 33, and the other end is in contact with the upper end portion of the intake valve 41. When the first cam 33 lifts one end of the first rocker arm 36 as the cam shaft 35 rotates, the first rocker arm 36 rotates counterclockwise. At the other end of the first rocker arm 36, the intake valve 41 is pressed downward and downward. In this way, the umbrella portion 41a opens the air inlet 31. When the cam shaft 35 rotates further, the position of the first cam 33 changes, and one end portion of the first rocker arm 36 cannot be lifted up by the first cam 33. As a result, the spring 41d pushes up the valve stem 41b obliquely upward, moves the intake valve 41 obliquely upward, and the umbrella portion 41a closes the intake port 31. The other end of the first rocker arm 36 is lifted up by the intake valve 41, and the first rocker arm 36 is rotated in the clockwise direction.

The second rocker arm 37 is rotatable about the shaft 37a. One end of the second rocker arm 37 is in contact with the second cam 34, and the other end is in contact with the lower end portion of the exhaust valve 42. The exhaust valve 42 is also driven in the same manner as the intake valve 41 by the second cam 34 and the second rocker arm 37.

The intake valve 41 and the exhaust valve 42 are movable parts. The oil pump 38 (see FIG. 4) in the crankcase 14 supplies oil to the intake valve 41 and the exhaust valve 42. Next, a mechanism for supplying oil to the intake valve 41 and the exhaust valve 42 will be described.

A plurality of passages are formed in the interior of the wall of the crankcase 14, the cylinder block 11, the cylinder head 15, and the head cover 16. The engine 13 includes an oil supply passage 50 formed by the passages. The arrow of Fig. 4 indicates a part of the flow direction of the oil supply passage 50. The oil system is supplied to each sliding portion through the oil supply passage 50. Hereinafter, each channel constituting the oil supply passage 50 will be described. Further, in the present embodiment, the oil supply passage for supplying oil from the oil pump 38 to the intake valve 41 is provided by the passages 53, 54, 55, 56, 57, 58, 59, 60, 61, 62 described below. And 63 constitutes. However, the oil supply passage for supplying oil from the oil pump 38 to the intake valve 41 is not limited to the oil supply passage including the above-described passage 53 or the like. The oil supply passage of the present invention includes only the cylinder block 11, the cylinder head 15, and the head cover. The inner passage of the wall of 16 may be, and the structure of the oil supply passage of the present invention is not limited by the structure of the embodiment at all.

As shown in Fig. 5, the bottom portion 14a of the crankcase 14 is formed by accumulating oil. The bottom portion 14a of the crankcase 14 is an oil storage portion. A passage 51 extending to the right is formed in the crankcase 14. An oil filter 39 is disposed to the left of the passage 51. The oil accumulated in the bottom portion 14a of the crankcase 14 flows into the passage 51 through the oil filter 39.

The right end of the passage 51 is connected to the passage 52 extending upward. An oil pump 38 is disposed above the passage 52. The passage 52 is connected to the suction port 38a of the oil pump 38. The discharge port 38b of the oil pump 38 is connected to a passage 53 (refer to Fig. 4) which extends obliquely upward toward the front. The front end of the passage 53 is connected to the passage 54 extending to the right. As shown in Figure 4, the right end of the passage 54 is connected to the upwardly extending passage 55.

As shown in Fig. 6, the upper end of the passage 55 is connected to the passage 56 extending to the left. The left end portion of the passage 56 is a passage 57 extending obliquely upward toward the front and a passage 70 extending obliquely downward and rearward. The oil flowing through the passage 70 is supplied to the crankshaft 12, the connecting rod 18, and the piston 17. The supplied oil drops to the bottom 14a of the crankcase 14. The channels 51-57 and the channel 70 are formed in the crankcase 14.

As shown in FIG. 4, a passage 58 connected to the passage 57 is formed between the crankcase 14 and the cylinder block 11. The upper end of the passage 58 is connected to a passage 59 extending obliquely upwardly forward. The passage 59 is formed inside the wall of the cylinder block 11.

The passage 59 is connected to a passage 60 extending obliquely upwardly forward. The front end portion of the passage 60 is branched into the passage 61 and the passage 71. As shown in Fig. 6, the passage 71 is connected to the passage 72 formed inside the cam shaft 35. Formed along the camshaft 35 A channel 73 extending toward the direction. The oil supplied to the passage 72 is discharged through the passage 73 to the outside of the cam shaft 35. The oil thus discharged to the outside of the cam shaft 35 lubricates the outer peripheral portion of the cam shaft 35, and is dripped by the action of gravity, and is supplied to the exhaust valve 42. The supplied oil drops to the bottom 14a of the crankcase 14. The passage 60 and the passage 71 are formed inside the wall of the cylinder head 15.

As shown in Fig. 4, the passage 61 extends obliquely upward toward the front. The front end of the passage 61 is connected to the passage 62 extending obliquely upward to the left. The passage 62 is connected to a passage 63 extending obliquely downward rearward. The passage 61, the passage 62, and the passage 63 are formed inside the wall of the head cover 16.

Fig. 7 is a view showing a portion of the head cover 16 and the like from the rear. In other words, Fig. 7 is a view showing a portion of the head cover 16 and the like from the direction of the arrow VII of Fig. 4. Figure 8 is a cross-sectional view taken along line VIII-VIII of Figure 7. Fig. 9 is a perspective view showing a portion of the head cover 16 as viewed from the rear.

As shown in FIG. 9, the columnar first protrusion 85 which protrudes downward is provided in the upper wall 16a of the head cover 16. The passage 61 is formed inside the first protruding portion 85. As shown in Fig. 8, the head cover 16 is provided rearward from the front wall 16b (strictly, obliquely downward, and hereinafter, unless otherwise specified, the "rear" includes not only the latter but also the rear obliquely). The second protruding portion 86 is protruded. Since the second projecting portion 86 is included in the wall facing the intake valve 41 in front of the intake valve 41, it corresponds to a portion of the front wall 16b of the head cover 16. Further, the second protruding portion 86 may also be referred to as a corner portion that spans the upper wall 16a and the front wall 16b. The thickness of the second protruding portion 86 is larger than the thickness of the upper wall 16a and the front wall 16b. The passage 62 and the passage 63 are formed inside the second projection 86.

An opening 64 is formed at the rear end of the passage 63. The opening 64 is formed in the head cover 16 The inner surface of the surface is higher than the intake valve 41 and is a position deviated from the position directly above the intake valve 41. The opening 64 is open toward the rear. Strictly speaking, the opening 64 is open slightly downward. As shown in FIG. 9, the first rib 81 is provided to the right of the opening 64. The portion of the upper wall 16a of the head cover 16 that is further to the right than the opening 64 is inclined obliquely downward. The first rib 81 is formed on the inner surface of the inclined portion so as to protrude downward. The first rib 81 extends substantially rearward. Strictly speaking, the first rib 81 extends obliquely downward rearward (see FIG. 8). The lower end portion of the first rib 81 is formed to have a tapered shape at the front end. As shown in FIGS. 7 and 8, the front end portion 81a of the first rib 81 is disposed at a position directly above the holder 41c of the intake valve 41.

As shown in FIG. 9, the second rib 82 surrounding the periphery of the opening 64 is provided in front of the second protrusion 86 of the front wall 16b. The second rib 82 is formed in a concave shape so as to surround one of the left, lower, and right sides of the opening 64. The second rib 82 functions as an oil receiving portion that receives the oil ejected from the opening 64. The right end portion of the second rib 82 is connected to the first rib 81. The first rib 81 and the second rib 82 are formed in a concave shape so as to surround the lower side and the side of the opening 64 as a whole.

As shown in Fig. 8, the lower end portion 86b of the second projecting portion 86 is located above the upper end portion 36t of the first rocker arm 36, the upper end portion 41ct of the retainer 41c, and the upper end portion 41bt of the valve stem 41b. The first rocker arm 36 is disposed further forward than the retainer 41c and the valve stem 41b. The second protruding portion 86 is disposed further forward than the first rocker arm 36, and the opening 64 is located further forward than the first rocker arm 36. Therefore, the opening 64 is located further forward than the retainer 41c and the valve stem 41b. Further, the opening 64 is located above the first rocker arm 36, the retainer 41c, and the valve stem 41b. As shown in Fig. 7, when viewed from the rear, the opening 64 is located at the first rocker arm. 36 is above the upper end portion 36t and the holder 41c.

As shown in FIG. 8, the first rocker arm 36 is disposed in front of the intake valve 41 and covered by the head cover 16. The intake valve 41 is covered by the head cover 16 and the cylinder head 15 (see also FIG. 3). The opening 64 is configured to supply not only oil to a portion of the intake valve 41 located inside the head cover 16, but also to a portion located inside the cylinder head 15.

When the crankshaft 12 rotates, the oil pump 38 coupled to the crankshaft 12 is driven. A portion of the oil accumulated in the bottom portion 14a of the crankcase 14 is ejected from the opening 64 via the passages 51-63. As shown in FIG. 4, the oil pump 38 is coupled to the crankshaft 12 via a gear 45. The oil pump 38 is driven by the crankshaft 12. The rotational speed of the oil pump 38 is increased or decreased depending on the rotational speed of the crankshaft 12. When the rotational speed of the crankshaft 12 is small, the rotational speed of the oil pump 38 becomes small, and when the rotational speed of the crankshaft 12 is large, the rotational speed of the oil pump 38 becomes large. The discharge amount and the discharge pressure of the oil pump 38 vary depending on the rotational speed of the crankshaft 12.

When the rotational speed of the crankshaft 12 is small, for example, when the locomotive 1 is idling, the discharge pressure of the oil pump 38 becomes small, and the spray force of the oil ejected from the opening 64 becomes small. In this case, the oil ejected from the opening 64 is transmitted to the inner surface of the head cover 16 to reach the first rib 81. Since the second rib 82 is provided around the opening 64, the oil that has flowed below the opening 64 is guided to the first rib 81 via the second rib 82. As indicated by an arrow F1 in FIG. 8, the oil flowing through the surface of the first rib 81 is dripped from the first rib 81 by the action of gravity, and is supplied to the first rocker arm 36 and the intake valve 41.

The front end portion 81a of the first rib 81 is located directly above the holder 41c of the intake valve 41. The oil dripped from the front end portion 81a of the first rib 81 is supplied to the intake valve 41. Further, the distal end portion 81a is also the lowermost end portion of the first rib 81, and is the most oily. The part that is easy to drip. The retainer 41c is a portion having a larger area in plan view than the valve stem 41b. The retainer 41c is the easiest part to block the oil. In this way, the front end portion 81a which is the portion of the first rib 81 which is most likely to drip is disposed above the holder 41c which is the portion of the intake valve 41 which is the easiest to block the oil, and can be disposed. The intake valve 41 supplies a sufficient amount of oil.

When the rotational speed of the crankshaft 12 is large, for example, when the locomotive 1 is traveling at a high speed, the discharge pressure of the oil pump 38 becomes high, so that the oil is strongly ejected from the opening 64. For example, oil is injected from the opening 64. As shown by an arrow F2 in Fig. 8, the discharged oil is directly supplied to the first rocker arm 36 and the intake valve 41.

As described above, the engine 13 is formed with the oil supply passage 50 at a position higher than the intake valve 41 in the inner surface of the head cover 16 and at a position deviated from the position directly above the intake valve 41. The opening 63 to which the passage 63 is connected. When the rotational speed of the crankshaft 12 is large, oil is strongly ejected from the opening 64. Therefore, even if the opening 64 is not located directly above the intake valve 41, oil can be supplied to the intake valve 41. On the other hand, when the rotational speed of the crankshaft 12 is small, the spray force of the oil ejected from the opening 64 becomes small. However, on the side of the opening 64, the first rib 81 in which the front end portion 81a is located directly above the holder 41c of the intake valve 41 is provided. The oil discharged from the opening 64 flows through the inner surface of the head cover 16 and the surface of the first rib 81, and drops from the front end portion 81a of the first rib 81 to the intake valve 41. Therefore, even if the opening 64 is not located directly above the intake valve 41, oil can be supplied to the intake valve 41. By the engine 13, even when the discharge pressure of the oil pump 38 is reduced to idling or the like, the oil can be favorably supplied to the intake valve 41.

Further, with the engine 13, the number of passages formed in the head cover 16 is small compared to the above-described prior art (refer to Document 1), so that the head cover 16 can be miniaturized.

As shown in FIG. 9, the inner surface of the head cover 16 is provided with a second rib 82 projecting from below the opening 64 and connected to the first rib 81. The oil that has flowed below the opening 64 is blocked by the second rib 82 and guided to the first rib 81. Therefore, the amount of oil supplied from the first rib 81 to the intake valve 41 can be increased. That is, when the rotation speed of the crankshaft 12 is small, a sufficient amount of oil can be supplied to the intake valve 41.

As shown in FIG. 9, in the present embodiment, the first ribs 81 and the second ribs 82 are formed in a concave shape so as to surround the lower side and the side of the opening 64. The second rib 82 also surrounds the left side of the opening 64 opposite to the first rib 81 of the opening 64. Therefore, more oil can be guided from the opening 64 to the first rib 81. Therefore, more oil can be supplied to the intake valve 41.

However, the shape and size of the second rib 82 are not particularly limited. For example, as shown in FIG. 10, instead of the concave second rib 82, a second rib 83 having a protrusion shape extending leftward from the first rib 81 may be provided. In this way, the second rib 83 may be disposed below one of the sides of the first rib 81 of the opening 64. Alternatively, the second rib may have a plate shape extending in the horizontal direction.

As shown in FIG. 9, the first rib 81 is formed on the inner surface of the upper wall 16a of the head cover 16. Thereby, a mechanism for supplying oil to the intake valve 41 when the rotational speed of the crankshaft 12 is small can be realized by a simple configuration.

As shown in FIG. 8, the opening 64 is located further forward than the front end 41f of the intake valve 41, and the first rib 81 extends obliquely downward rearward. The opening 64 is formed on the inner surface of the front wall 16b of the head cover 16 (in detail, the surface of the second protrusion 86 of the front wall 16b), and the first rib 81 extends obliquely downward rearward. Thereby, the shape of the shape of the engine 13 extending toward the front or the front obliquely upward by the cylinder axis L1 (refer to FIG. 3) can be utilized, and the rotational speed of the crankshaft 12 can be realized by a simple configuration. The mechanism for supplying oil to the intake valve 41 at the time.

As shown in FIGS. 7 and 9, the lower end portion of the first rib 81 is formed to have a tapered shape at the lower end. The lower surface of the first rib 81 is curved downward in a convex shape. Thereby, the oil smoothly dripped from the first rib 81. Therefore, oil can be smoothly supplied to the intake valve 41 from the first rib 81.

However, the shape of the first rib 81 is not particularly limited. For example, as shown in FIG. 11, the lower end of the first rib 81 may be formed in an inverted triangular shape. The lower end of the first rib 81 can also be pointed. Further, as shown in FIG. 12, the lower end portion of the first rib 81 may not necessarily be formed to have a tapered shape at the tip end.

In the intake valve 41, the cage 41c has a larger plan view area than the valve stem 41b (see FIG. 7 and the like). As shown in Fig. 7, the front end portion 81a of the first rib 81 is located directly above the holder 41c. More specifically, the front end portion 81a of the first rib 81 is located directly above the right end portion of the holder 41c. By the first rib 81, the oil can be made to flow down to a portion of the intake valve 41 having a large area of plan view. Thereby, oil can be stably supplied to the intake valve 41.

As shown in FIG. 9, the head cover 16 includes a first protruding portion 85 that protrudes downward from the inner surface of the upper wall 16a. Moreover, as shown in FIG. 8, the head cover 16 includes the 2nd protrusion part 86 which protrudes rearward from the inner surface of the front wall 16b. The passage 61 is formed inside the first protruding portion 85, and the passage 62 and the passage 63 are formed inside the second protruding portion 86. The thickness of the first protruding portion 85 and the second protruding portion 86 is larger than the other portions. Therefore, it is not necessary to form the passages 61 to 63 in the thin portion, so that the passages 61 to 63 can be easily formed. Further, it is possible to prevent the strength of the head cover 16 from decreasing as the passages 61 to 63 are formed. The enlargement of the head cover 16 can be suppressed.

In the present embodiment, the opening 64 is formed in the front wall 16b of the head cover 16. The inner surface. However, the opening 64 may also be formed on the inner surface of the upper wall 16a of the head cover 16. Further, the opening 64 may be formed across the inner surface of the upper wall 16a of the head cover 16 and the inner surface of the front wall 16b. The opening 64 may also be formed at a boundary portion between the inner surface of the upper wall 16a and the inner surface of the front wall 16b.

As shown in Fig. 9, in the present embodiment, the lower end of the first rib 81 is disposed at a position higher than the lower end of the second rib 82. However, as shown in FIG. 13, the lower end 81b of the first rib 81 and the lower end 82b of the second rib 82 may be disposed at the same height. Further, the lower end of the first rib 81 may be disposed at a lower position than the lower end of the second rib 82.

The first rib 81 may not extend rearward, and may be inclined to the left or right. The first rib 81 may not be linear or curved. The shape and size of the first rib 81 are not particularly limited.

In the present embodiment, the front end portion 81a of the first rib 81 is located directly above the holder 41c. However, the position of the front end portion 81a of the first rib 81 is not particularly limited. The front end portion 81a of the first rib 81 may also be located directly above the valve stem 41b. The front end portion 81a of the first rib 81 can be disposed at any position where oil can be supplied to the intake valve 41.

In the present embodiment, a sealed space in which the oil pump 38 is housed is formed inside the crankcase 14. However, it is also possible to form a sealed space in which the oil pump 38 is housed by combining the crankcase with one or more other housings. The "casing body" of the present invention together with the cylinder block or the like forms a closed space for accommodating the crankshaft and the oil pump. The "casing" may be composed only of a crankcase, or may be constituted by a crankcase and other casings. The "box" can be a single part or a combination of a plurality of parts.

In the present embodiment, the crankcase 14 and the cylinder block 11 are not integrated but are assembled to each other. However, the crankcase 14 and the cylinder block 11 may also be integral. The engine 13 is not limited to a single cylinder engine, but may also be a multi-cylinder engine. For example, in a multi-cylinder engine, the upper and lower portions of the crankcase 14 may be separately formed, and the cylinder block 11 may be integrated with the upper portion of the crankcase 14.

1‧‧‧ locomotive

2‧‧‧ body frame

2A‧‧‧ head tube

2B‧‧‧Side frame

3‧‧‧ pivot

4‧‧‧ body cover

5‧‧‧ Front fork

6‧‧‧Hands

7‧‧‧ front wheel

8‧‧‧buffer unit

9‧‧‧ Rear wheel

10‧‧‧ engine unit

11‧‧‧Cylinder block

12‧‧‧ crankshaft

13‧‧‧ Engine

14‧‧‧ crankcase

14a‧‧‧ bottom

15‧‧‧Cylinder head

16‧‧‧ head cover

16a‧‧‧Upper wall

16b‧‧‧ front wall

17‧‧‧Piston

18‧‧‧ Connecting rod

19‧‧‧ combustion chamber

21‧‧‧1st pulley

22‧‧‧2nd pulley

23‧‧‧V-shaped conveyor belt

24‧‧‧ Spindle

25‧‧‧ Rear axle

29‧‧‧Air cleaner

30‧‧‧Transmission box

31‧‧‧Air inlet

32‧‧‧Exhaust port

33‧‧‧1st cam

34‧‧‧2nd cam

35‧‧‧Camshaft

36‧‧‧1st rocker

36a‧‧‧Axis

36t‧‧‧Upper

37‧‧‧2nd rocker

37a‧‧‧Axis

38‧‧‧ oil pump

38a‧‧‧Inhalation

38b‧‧‧Spray outlet

39‧‧‧ Oil filter

40‧‧‧Chain

40a‧‧‧Sprocket

41‧‧‧Intake valve

41a‧‧‧ Umbrella Department

41b‧‧‧ valve stem

41bt‧‧‧ upper end

41c‧‧‧keeper

41ct‧‧‧ upper end

41d‧‧‧Spring

41f‧‧‧ front end

42‧‧‧Exhaust valve

45‧‧‧ Gears

50‧‧‧ oil supply channel

51‧‧‧ channel

52‧‧‧ channel

53‧‧‧ channel

54‧‧‧ channel

55‧‧‧ channel

56‧‧‧ channel

57‧‧‧ channel

58‧‧‧ channel

59‧‧‧ channel

60‧‧‧ channel

61‧‧‧ passage

62‧‧‧ channel

63‧‧‧ channel

64‧‧‧ openings

70‧‧‧ channel

71‧‧‧ channel

72‧‧‧ channel

73‧‧‧ channel

81‧‧‧1st rib

81a‧‧‧ front end

81b‧‧‧Bottom

82‧‧‧2nd rib

82b‧‧‧Bottom

83‧‧‧2nd rib

85‧‧‧1st protrusion

86‧‧‧2nd protrusion

86b‧‧‧Bottom

F‧‧‧ directions

L1‧‧‧Cylinder axis

Re‧‧ Direction

Figure 1 is a side view of the locomotive.

Figure 2 is a cross-sectional view of the engine unit.

Figure 3 is a vertical cross-sectional view of the engine unit.

Fig. 4 is a partial side elevational view showing the engine of the oil supply passage.

Figure 5 is a cross-sectional view taken along line V-V of Figure 4.

Figure 6 is a cross-sectional view taken along line VI-VI of Figure 4.

Fig. 7 is a view showing the head cover, the intake valve, and the like from the direction of the arrow VII in Fig. 4.

Fig. 8 is a cross-sectional view showing the cross section of the line VIII-VIII of Fig. 7, and the cross section of the cylinder head or the like.

Fig. 9 is a perspective view showing a configuration of one portion of the oil supply passage, the first rib, the second rib, and the like.

Fig. 10 is a perspective view showing a first rib, a second rib, and the like of a modification.

Fig. 11 is a front view of a first rib of a modification.

Fig. 12 is a front view of a first rib of another modification.

Fig. 13 is a front view showing a first rib and a second rib according to another modification.

15‧‧‧Cylinder head

16‧‧‧ head cover

16a‧‧‧Upper wall

16b‧‧‧ front wall

36‧‧‧1st rocker

36a‧‧‧Axis

36t‧‧‧Upper

41‧‧‧Intake valve

41b‧‧‧ valve stem

41bt‧‧‧ upper end

41c‧‧‧keeper

41ct‧‧‧ upper end

41d‧‧‧Spring

41f‧‧‧ front end

62‧‧‧ channel

63‧‧‧ channel

64‧‧‧ openings

81‧‧‧1st rib

81a‧‧‧ front end

82‧‧‧2nd rib

86‧‧‧2nd protrusion

86b‧‧‧Bottom

F‧‧‧ directions

Re‧‧ Direction

Claims (9)

An internal combustion engine includes: a casing that houses a crankshaft; a cylinder block that is integrally or separately formed with the casing, and extends from the casing toward the front or the front obliquely upward; the cylinder head is fixed to the cylinder block a front end portion, which divides the combustion chamber together with the cylinder block, and is formed with an intake port and an exhaust port facing the combustion chamber; a head cover fixed to the front end portion of the cylinder head; and a valve in the head cover and the cylinder And at least a part of the inside of the head is disposed above the cylinder axis, and opens and closes one of the air inlet and the exhaust port; the oil pump is disposed inside the box and driven by the crank shaft, and according to the above a rotation speed of the crankshaft to change the discharge amount; and an oil supply passage including a passage formed in the cylinder block, the cylinder head, and a wall of the head cover, and guiding the oil sprayed from the oil pump; and the head cover An opening in the inner surface that is higher than the valve and is offset from a position directly above the valve, and an opening connected to the oil supply passage is formed, and a first rib protruding from an inner surface of the head cover, wherein one end is located laterally of the opening, and the other end is located directly above the valve, and includes a second rib, at least a portion of the second rib is from an inner surface of the head cover The opening protrudes downward and is connected to the first rib. The internal combustion engine of claim 1, wherein the first rib and the second rib are formed in a concave shape so as to surround a lower side and a side of the opening. The internal combustion engine of claim 1, wherein the first rib is formed on an inner surface of the upper wall of the head cover. The internal combustion engine of claim 1, wherein the opening is located forward of the front end of the valve, and the first rib extends obliquely downward rearward. The internal combustion engine of claim 1, wherein the opening is formed on an inner surface of the front wall of the head cover, and the first rib extends obliquely downward rearward. The internal combustion engine of claim 1, wherein the lower end of the first rib is formed to have a tapered shape toward the lower side. The internal combustion engine of claim 1, wherein the valve comprises: a valve stem extending obliquely upwardly forward; and a retainer disposed at a front end of the valve stem; and the other end of the first rib being located at the front of the retainer Above. The internal combustion engine of claim 1, wherein the head cover comprises: a first protruding portion that protrudes downward from an inner surface of the upper wall; and a second protruding portion that protrudes rearward from an inner surface of the front wall; and the oil supply passage The channel formed inside the first protruding portion and the channel formed inside the second protruding portion are included. A locomotive having the internal combustion engine of claim 1.