JP6700602B2 - Lubricant oil injection structure for internal combustion engine - Google Patents

Description

  The present invention relates to a lubricating oil injection structure for injecting lubricating oil into an internal combustion engine.

  2. Description of the Related Art As a lubricating oil injection structure for injecting lubricating oil into an internal combustion engine, for example, one including an injection pipe and an outer wall portion is known as described in Patent Document 1. The injection pipe projects upward from the head cover main body, which is a main part of the cylinder head cover, at one end of the head cover main body in the cylinder arrangement direction of the internal combustion engine. The injection pipe has a lubricating oil injection port at its upper end. Then, the filler cap is detachably attached to the upper end portion of the injection pipe via the gasket, thereby closing and opening the injection port. This mounting is done by screwing the filler cap onto the injection tube.

  The outer wall portion is provided between the outer peripheral surface of the injection pipe and the head cover body. The outer wall portion surrounds at least a part of the outer peripheral surface of the injection pipe in the circumferential direction via a hollow portion. The outer wall portion enhances the rigidity of the injection tube. Further, the lower ends of the injection pipe and the hollow portion are open to face the internal space of the head cover body.

  Therefore, even if the gasket is dented by the heat generated by the internal combustion engine or the vibration of the internal combustion engine is transmitted to the injection pipe with the axial force (tightening force) of the filler cap reduced, the filler cap is prevented from rotating in the loosening direction. To be done.

JP, 2010-59936, A

  By the way, in a general lubricating oil injection structure for an internal combustion engine, it is required that a large amount of lubricating oil can be injected into the internal combustion engine through the injection pipe when the lubricating oil is replaced, and that the injection property is good. Since other parts of the internal combustion engine and the like are arranged in the vicinity of the cylinder head cover, there is a limitation in increasing the diameter of the injection pipe in order to avoid interference with these parts. This also applies to the lubricating oil injection structure described in Patent Document 1 above. Further, in Patent Document 1, no particular consideration is given to the structure for coping with the above requirement.

  The present invention has been made in view of such circumstances, and an object thereof is to provide a lubricating oil injection structure for an internal combustion engine capable of improving the injection property of lubricating oil while increasing the rigidity of the injection pipe. To do.

  A lubricating oil injection structure for an internal combustion engine which solves the above problems is applied to a cylinder head cover whose main part is composed of a head cover body, which projects upward from the head cover body and which lubricates the upper end portion of itself. An injection pipe having an oil injection port, the filler cap being removably attached from above to close and open the injection port, and between the outer peripheral surface of the injection pipe and the head cover body. An outer wall portion that is provided and surrounds at least a part of the outer peripheral surface of the injection pipe in the circumferential direction via a hollow portion, and at least a part of the lower end portion of each of the injection pipe and the hollow portion is the A lubricating oil injection structure for an internal combustion engine opened to face an internal space of a head cover body, wherein the internal space of the injection pipe is provided at least at a lower portion of the injection pipe surrounded by the outer wall portion. And a communication portion that communicates with the hollow portion.

  According to the above configuration, by adding the outer wall portion, the injection pipe and the head cover body are connected to each other by the outer wall portion, and the rigidity of the injection pipe is enhanced. Therefore, even if the vibration of the internal combustion engine is transmitted to the injection pipe, the injection pipe does not easily vibrate.

  Further, at least a part of the lower end portion of the injection pipe is opened so as to face the internal space of the head cover body. Therefore, when the lubricating oil is injected from the injection port, a part of the lubricating oil is supplied to the inside of the internal combustion engine from the open portion of the lower end portion after flowing down the injection pipe.

  In addition, the communication space is provided at least in the lower portion of the injection pipe surrounded by the outer wall portion, so that the internal space of the injection pipe and the cavity are communicated with each other. At least a part of the lower end of the hollow portion faces the inner space of the head cover body and is open. Therefore, a part of the lubricating oil injected into the injection pipe enters the cavity through the communicating portion, flows down through the cavity, and is supplied into the internal combustion engine from the open portion at the lower end thereof.

  Therefore, the amount of lubricating oil that can be injected into the internal combustion engine through the injection pipe is increased by the amount of the lubricating oil that passes through the open portion at the lower end of the cavity, and the injection performance is improved.

  According to the lubricating oil injection structure of the internal combustion engine, it is possible to improve the injection property of the lubricating oil while increasing the rigidity of the injection pipe.

It is a figure showing one embodiment which materialized a lubricating oil pouring structure of an internal-combustion engine, and is a perspective view of a cylinder head cover to which the lubricating oil pouring structure is applied. FIG. 3 is a plan view of a cylinder head cover with a baffle plate attached thereto according to an embodiment. Sectional drawing which followed the 3-3 line of FIG. In one embodiment, a partial plan view showing the injection pipe with the filler cap removed and the peripheral portion thereof. In one embodiment, a bottom view of a cylinder head cover with a baffle plate attached. FIG. 6 is a sectional view taken along line 6-6 of FIG. 5.

Hereinafter, an embodiment of a lubricating oil injection structure applied to an internal combustion engine for a vehicle will be described with reference to the drawings.
The internal combustion engine 10 shown in FIGS. 3 and 6 has a plurality of cylinders arranged in a row. The cylinder head 11 of the internal combustion engine 10 incorporates a valve mechanism that opens and closes intake and exhaust valves for each cylinder. The intake/exhaust valves are opened/closed by rotating an intake/exhaust camshaft extending in the cylinder arrangement direction. A rotation transmission member 12, such as a sprocket, is provided at one end of the intake/exhaust camshaft in the same direction, and rotation of the crankshaft is absorbed or exhausted via the timing chain, the rotation transmission member 12, or the like. The intake/exhaust valve is driven by being transmitted to the camshaft.

  A cylinder head cover 14 is arranged on the cylinder head 11. The main part of the cylinder head cover 14 is composed of a head cover body 15. An end portion 15a of the head cover main body 15 on the same side as the rotation transmitting member 12 in the cylinder arrangement direction is formed wider than other portions in the same direction in order to dispose the rotation transmitting member 12 and the like here (Fig. 2).

  As shown in FIGS. 1 and 2, a flange portion 16 is formed on the lower end peripheral portion of the head cover body 15, and the flange portion 16 is arranged on the cylinder head 11 via the gasket 13 (FIG. 6). reference). Fastening portions 17 each having a bolt insertion hole 17a are formed at a plurality of locations on the flange portion 16. The head cover body 15 is fastened to the cylinder head 11 by the bolts inserted through the bolt insertion holes 17a.

  A baffle plate 19 for reducing the amount of oil contained in the blow-by gas taken away is attached to the head cover body 15 from the back side of the head cover body 15 by fixing means such as welding (FIG. 3, FIG. (See FIGS. 5 and 6). The head cover main body 15 has the same number of mounting holes 20 as the number of cylinders for mounting the ignition plugs for each cylinder. Therefore, the arrangement direction of the mounting holes 20 matches the cylinder arrangement direction.

  As shown in FIGS. 1 and 3, a general portion 21, a first step portion 22 and a second step portion 23 are formed on the end portion 15 a of the head cover body 15. The first step portion 22 is formed at a position lower than the general portion 21 at a position separated from the general portion 21. The second step portion 23 is formed between the general portion 21 and the first step portion 22 at a position lower than the first step portion 22.

  An injection pipe 25 for injecting the lubricating oil O1 into the internal combustion engine 10 protrudes upward from the first step portion 22. The injection pipe 25 is formed as a part of the cylinder head cover 14. The upper end portion of the injection pipe 25 is located higher than the general portion 21.

  The injection pipe 25 includes a large diameter portion 26, an upper taper portion 27, a small diameter portion 28, a lower taper portion 29, and a bottom portion 31 in order from top to bottom. The large diameter portion 26 is located above the injection pipe 25 and has a circular tubular shape. The small diameter portion 28 has a circular tubular shape with a diameter slightly smaller than that of the large diameter portion 26. The upper taper portion 27 is located between the large diameter portion 26 and the small diameter portion 28, and the diameter thereof becomes smaller toward the lower side. The lower taper portion 29 is located between the small diameter portion 28 and the bottom portion 31 and has a smaller diameter toward the lower side.

  The upper end of the internal space of the large-diameter portion 26 is open, and this opening constitutes the inlet 32. A filler cap 35 is detachably attached to the injection pipe 25 from the upper side in order to close and open the injection port 32. More specifically, the filler cap 35 includes a head portion 36 and a shaft portion 37 having a diameter smaller than that of the head portion 36 and projecting downward from the head portion 36. The part 38 is formed. Further, a female screw portion 33 is formed on the inner peripheral surface of the large diameter portion 26 of the injection pipe 25. Then, with the gasket 34 interposed between the large diameter portion 26 of the injection pipe 25 and the head portion 36 of the filler cap 35, the male screw portion 38 is screwed into the female screw portion 33, so that the filler cap 35 Is fastened to the injection pipe 25 and the injection port 32 is closed. The axial force (tightening force) of the filler cap 35 is secured by the reaction force generated by pressing the gasket 34.

  A part of the injection pipe 25 in the radial direction protrudes from the end portion 15a of the head cover body 15 in the cylinder arrangement direction. In the present embodiment, approximately half of the injection pipe 25 in the radial direction protrudes from the end 15a.

  An outer wall portion 41 is provided between the outer peripheral surface of the large diameter portion 26 of the injection pipe 25 and the second step portion 23 of the head cover body 15. The outer wall portion 41 surrounds at least a part of the outer peripheral surface of the injection pipe 25 in the circumferential direction via a cavity portion 44. In the present embodiment, the outer wall portion 41 is provided for a portion of the injection pipe 25 that does not protrude from the end portion 15a of the head cover body 15. The lower end portion of the outer wall portion 41 is connected to the second step portion 23, and the upper end portion of the outer wall portion 41 is connected to the upper end portion of the large diameter portion 26.

  As shown in FIG. 4, the outer wall portion 41 includes a curved portion 42 and a protrusion 43 that is adjacent to the curved portion 42 in the circumferential direction of the injection tube 25. The curved portion 42 has a curved surface 42a that extends in the up-down direction while being curved in the circumferential direction so as to form a part of a cylinder. The projecting portion 43 has a pair of flat surfaces 43 a that extend in the up-down direction while being adjacent to each other in the circumferential direction, and project outward in the radial direction of the injection pipe 25.

  Further, as shown in FIGS. 1 and 3, in the head cover main body 15, a plurality of ribs 24 extending in the vertical direction are provided in the first step portion 22, which is a portion below the portion where the injection pipe 25 protrudes. ing.

  As shown in FIG. 3, at least a part of the lower end of the hollow portion 44 faces the internal space 47 of the head cover body 15 and is open. The bottom portion 31 forming a part of the lower end portion of the injection pipe 25 is opened to face the internal space 47 of the head cover body 15 at a portion not protruding from the end portion 15a of the head cover body 15. In other words, at least a part of the lower end of the injection pipe 25 faces the internal space 47 and is open. This portion is referred to as an open portion 31a of the bottom portion 31.

  Further, in the injection pipe 25, a communication portion 45 that connects the internal space 46 of the injection pipe 25 and the hollow portion 44 is formed at least at a lower portion of a portion surrounded by the outer wall portion 41. Here, the small diameter portion 28 and the lower taper portion 29 of the injection pipe 25, which are portions not protruding from the end portion 15a of the head cover body 15, are cut out to form the communication portion 45. The communication portion 45 is formed in a state of being connected to the open portion 31 a of the bottom portion 31 of the injection pipe 25. The upper end of the communication portion 45 is located at the boundary between the upper taper portion 27 and the small diameter portion 28. It can be said that this boundary portion is the highest possible position or a position close thereto in order to secure the strength of the female screw portion 33. The open portion 31a and the communication portion 45 form an outlet for the lubricating oil O1 in the injection pipe 25.

  Further, as shown in FIGS. 5 and 6, a part of the baffle plate 19 is filled with the lubricating oil O2 scattered by the rotation transmission member 12 in the injection pipe 25 due to the operation of the valve operating mechanism of the internal combustion engine 10. A guide portion 19a that leads to the inlet 32 is formed. The guide portion 19a is located below the communication portion 45 in the injection pipe 25 (see FIG. 3). The guide portion 19a is arranged in a state of being inclined with respect to the horizontal direction so that the downstream portion in the scattering direction of the lubricating oil O2 is closer (higher) to the injection pipe 25 than the upstream portion.

Next, the operation and effect of the present embodiment configured as described above will be described separately for each situation.
<When the internal combustion engine 10 is operating>
(1) As shown in FIGS. 1 and 3, since the injection pipe 25 projects upward from the head cover body 15 and has an elongated shape, there is the following concern. When the heat generated by the internal combustion engine 10 is transferred to the gasket 34, the gasket 34 becomes tired and the dimension in the height direction becomes smaller. The reaction force generated by pressing the gasket 34 is reduced, and the axial force (tightening force) of the filler cap 35 is reduced. In this state, when the vibration of the internal combustion engine 10 is transmitted to the injection pipe 25 and the injection pipe 25 vibrates, the filler cap 35 may rotate in the loosening direction.

  In this respect, the outer peripheral surface of the injection pipe 25 and the second step portion 23 of the head cover body 15 are connected by the outer wall portion 41, and the rigidity of the injection pipe 25 is enhanced by the outer wall portion 41. Particularly, in the present embodiment, the outer wall portion 41 projects upward from the second step portion 23 and is connected to the upper end portion of the large diameter portion 26 of the injection pipe 25 at the upper end portion thereof. In this way, the rigidity of the injection tube 25 is increased over a wider area in the height direction by the outer wall portion 41 provided over substantially the entire area in the height direction of the injection tube 25.

  Further, as shown in FIG. 4, the outer wall portion 41 has a configuration in which, in addition to the curved portion 42 having the curved surface 42a, a projection 43 having a pair of flat surfaces 43a adjacent in the circumferential direction, the outer wall portion 41 has the same configuration. Rigidity of the injection tube 25 is effectively enhanced as compared with the case where 41 is constituted only by the curved portion 42.

In addition, a plurality of ribs 24 provided on the first step portion 22 below the injection pipe 25 are connected to the bottom portion 31 to increase the rigidity of the injection pipe 25.
As described above, since the rigidity of the injection pipe 25 is increased, even if the vibration of the internal combustion engine 10 is transmitted, the injection pipe 25 is less likely to vibrate. Therefore, as described above, even if the gasket 34 is depressed by the heat of the internal combustion engine 10, the filler cap 35 is unlikely to rotate in the loosening direction.

  (2) As shown in FIGS. 5 and 6, when the internal combustion engine 10 is operating, the rotating transmission member 12 causes the lubricating oil O2 to be scattered. A part of the lubricating oil O2 is inclined by the guide portion 19a so that the downstream portion is closer (higher) to the injection pipe 25 than the upstream portion, as indicated by the two-dot chain line arrow in FIG. You can change to the direction you did. The lubricating oil O2 is guided to the injection port 32 of the injection pipe 25 by being scattered in the changed direction. At this time, since the communication portion 45 is formed above the guide portion 19a (see FIG. 3), the lubricating oil O2 easily enters the injection pipe 25 by passing through the communication portion 45. The lubricating oil O2 is applied to the back surface of the shaft portion 37 of the filler cap 35.

  Therefore, even if the moisture contained in the lubricating oil is condensed and the lubricating oil becomes cloudy and adheres to the back surface of the shaft portion 37, the lubricating oil O2 guided by the guide portion 19a as described above is removed. By hitting the back surface of the shaft portion 37 of the filler cap 35, the clouded lubricating oil can be scraped off from the filler cap 35.

<When injecting lubricating oil O1>
When the lubricating oil O1 is added to the internal combustion engine 10 or the lubricating oil O1 is replaced (oil replacement), the filler cap 35 is removed from the injection pipe 25 as shown in FIG. 4 when the internal combustion engine 10 is stopped. And the inlet 32 is opened. Then, the lubricating oil O1 is injected from the injection port 32, as shown by the chain double-dashed line in FIG.

  Here, the open portion 31 a of the lower end portion (bottom portion 31) of the injection pipe 25 is opened so as to face the internal space 47 of the head cover body 15. Therefore, a part of the lubricating oil O1 injected from the injection port 32 flows down the injection pipe 25 and then is supplied into the internal combustion engine 10 from the open portion 31a of the bottom portion 31.

  In particular, in the portion of the injection pipe 25 that protrudes from the end portion 15a of the head cover body 15 in the cylinder arrangement direction, the lower end portion of the injection pipe 25 is closed by the bottom portion 31. The open portion 31a of the lower end portion of the injection pipe 25 facing the internal space 47 of the head cover body 15 becomes smaller accordingly. If the communication portion 45 is not provided, the outflow port of the injection pipe 25 is composed of only the open portion 31a, and the outflow property of the lubricating oil is not sufficient. The amount of the lubricating oil O1 that can be injected into the injection pipe 25 from the injection port 32 is small, and the injection property is not good.

  However, the communication space 45 is provided in at least a lower portion of the injection pipe 25 surrounded by the outer wall portion 41, so that the internal space 46 of the injection pipe 25 and the hollow portion 44 are communicated with each other. At least a part of the lower end of the hollow portion 44 faces the internal space 47 of the head cover body 15 and is open.

  Therefore, a part of the lubricating oil O1 injected into the injection pipe 25 enters the hollow portion 44 through the communication portion 45, flows down through the hollow portion 44, and flows from the open portion 44a at the lower end portion of the internal combustion engine 10. Supplied internally.

Therefore, the amount of the lubricating oil O1 that can be injected into the internal combustion engine 10 through the injection pipe 25 is increased by the amount of the lubricating oil O1 that passes through the open portion 44a of the hollow portion 44, and the injectability is improved.
Particularly, in the present embodiment, the communication portion 45 is formed in a state of being connected to the open portion 31a of the bottom portion 31 of the injection pipe 25. Therefore, the cross-sectional area of the outlet of the lubricating oil O1 in the injection pipe 25 can be efficiently increased as compared with the case where the communication portion 45 is separated from the open portion 31a.

  Further, the upper end portion of the communication portion 45 is located at the highest possible position or a position close thereto in order to secure the strength of the female screw portion 33. This is also effective in efficiently increasing the cross-sectional area of the outlet of the injection pipe 25.

  Further, in the present embodiment in which approximately half of the injection pipe 25 in the radial direction protrudes from the end portion 15a of the head cover body 15, in the lower end portion of the injection pipe 25, an open portion 31a facing the internal space 47 of the head cover body 15. Becomes smaller, which greatly affects the amount of lubricating oil O1 that can be injected into the internal combustion engine 10 through the injection pipe 25. However, by providing the communication portion 45 as described above, it is possible to efficiently increase the cross-sectional area of the outlet of the injection pipe 25 and reduce the influence on the injection amount of the lubricating oil O1. As a result, a part of the injected lubricating oil O1 can be suppressed from overflowing from the injection port 32.

  Such an effect becomes greater as the amount of the injection pipe 25 protruding from the end 15a increases. This is because, of the bottom portion 31 of the injection pipe 25, the portion protruding from the end portion 15a increases, and the open portion 31a decreases accordingly.

  In addition, also in Patent Document 1, the injection pipe is surrounded by the outer wall portion through the cavity. Then, the lower ends of the injection pipe and the cavity are opened so as to face the inner space of the head cover body. However, the injection pipe is not provided with a portion corresponding to the communication portion 45 in the present embodiment. This is because there is a description that “the cavity prevents the lubricating oil scattered in the head cover from jumping into the injection pipe”, and for that purpose, it is necessary to extend the injection pipe downward as much as possible. .. Therefore, in Patent Document 1, the effect of improving the injection property as in the present embodiment cannot be expected.

<At inspection>
The filler cap 35 may be removed from the injection pipe 25 and the back surface of the shaft portion 37 of the filler cap 35 may be visually confirmed in a regular inspection of the vehicle. At this time, if the cloudy lubricating oil is attached to the shaft portion 37, there is a possibility that the internal combustion engine 10 is erroneously determined to be out of order.

  However, in the present embodiment, as described above, the scattered lubricating oil O2 is applied to the back surface of the shaft portion 37 to scrape off the turbid lubricating oil. It is unlikely that the cloudy lubricating oil will continue to adhere to the back surface of the shaft portion 37. Therefore, it is unlikely that a malfunction is erroneously determined during inspection or the like.

According to this embodiment, the following actions and effects other than the above can be obtained.
-When outside air such as running wind flows outside the cylinder head cover 14 when the vehicle is running, the heat in the injection pipe 25 is released to the outside air. The oil droplets of the lubricating oil that have entered the injection pipe 25 are cooled, the moisture in the lubricating oil condenses, and the lubricating oil becomes cloudy. The deterioration of the entire lubricating oil is accelerated.

However, in the present embodiment, the cavity 44 exerts a heat insulating effect, and the heat in the injection pipe 25 is less likely to be released to the outside air. It is possible to suppress the clouding of the lubricating oil and suppress deterioration of the lubricating oil.
The injection pipe 25 projects upward, and a filler cap 35 is attached to the upper end of the injection pipe 25. Therefore, the work of attaching and detaching the filler cap 35 is easy and the workability is good.

Further, since the injection port 32 is located at a high position, it is easy to inject the lubricating oil O1.
When the head cover body 15 made of resin is molded by a molding die, it is particularly required that the female screw portion 33 be molded with high accuracy. For that purpose, it is desirable that the peripheral portion of the molded female screw portion 33 be cooled. In this respect, in the head cover body 15 of the present embodiment, the outer wall portion 41 is formed around the injection pipe 25 having the female screw portion 33 via the cavity portion 44. Therefore, by disposing the cooling pipe inside the site where the cavity 44 is formed in the forming die, the female screw portion 33 can be efficiently cooled and sink marks or the like can be made less likely to occur.

The above embodiment can be implemented as a modified example in which the following modifications are made.
The injection pipe 25 may be arranged at a position in the head cover main body 15 that does not protrude from one end portion 15a in the cylinder arrangement direction of the internal combustion engine. In this case, many portions (including all) of the lower end portion of the injection pipe 25 may be opened to face the internal space 47 of the head cover body 15. Further, the injection pipe 25 may be arranged at a position protruding from the end portion 15a by an amount smaller or larger than that in the above-described embodiment.

  The entire outer peripheral surface of the injection pipe 25 may be surrounded by the outer wall portion 41 via the cavity 44. In this case, many portions (including all) of the lower end of the hollow portion 44 may be opened so as to face the internal space 47 of the head cover body 15.

The injection pipe 25 may protrude upward from the head cover main body 15 with a part of the injection pipe 25 protruding from the corner portion of the end portion 15a.
The position of the upper end of the communication portion 45 may be changed to a position lower than that in the above embodiment.

  The communication portion 45 is formed at a position apart from the open portion 31a of the bottom portion 31 of the injection pipe 25, provided that it is formed at least at a lower portion of the injection pipe 25 surrounded by the outer wall portion 41. You may.

  The communication part 45 may be provided at a plurality of positions in the circumferential direction of the injection pipe 25.

  DESCRIPTION OF SYMBOLS 10... Internal combustion engine, 12... Rotation transmission member, 14... Cylinder head cover, 15... Head cover main body, 15a... End part, 19... Baffle plate, 19a... Guide part, 25... Injection pipe, 31... Bottom part, 31a, 44a... Open Portion, 32... Injection port, 35... Filler cap, 41... Outer wall portion, 42... Curved portion, 42a... Curved surface, 43... Projection portion, 43a... Flat surface, 44... Cavity portion, 45... Communication portion, 46... Internal space of pipe, 47... Internal space of head cover body, O1, O2... Lubricating oil.

Claims (6)

The main part is a lubricating oil injection structure applied to the cylinder head cover composed of the head cover body,
Injection that projects upward from the head cover body and has a lubricating oil injection port at its upper end, and that a filler cap is detachably attached from the upper side to close and open the injection port With a tube,
An outer wall portion that is provided between the outer peripheral surface of the injection pipe and the head cover body, and that surrounds at least a part of the outer peripheral surface of the injection pipe in the circumferential direction via a cavity portion; A lubricating oil injection structure for an internal combustion engine, wherein at least a part of a lower end portion of each of the hollow portions faces an internal space of the head cover body and is opened.
A part of the injection pipe in the circumferential direction, in which at least a lower part of a portion surrounded by the outer wall portion, a communication portion is formed that connects the internal space of the injection pipe and the cavity. Engine lubrication oil injection structure. A part of the injection pipe extends from one end of the head cover body in the cylinder arrangement direction of the internal combustion engine in the same direction,
The outer wall portion, of the injection pipe, surrounds a portion that does not protrude from the end portion of the head cover body via the cavity portion,
The lubricating oil injection structure for an internal combustion engine according to claim 1, wherein the injection pipe is opened to face an internal space of the head cover body in a portion of the bottom portion thereof that does not protrude from the end portion.   The lubricating oil injection structure for an internal combustion engine according to claim 2, wherein the communication portion is formed in a state of being connected to an open portion of a bottom portion of the injection pipe. The outer wall portion is
A curved portion having a curved surface that extends in the vertical direction in a state of being curved in the circumferential direction so as to form a part of a cylinder;
The projection which has a pair of flat surface which respectively extends in an up-down direction in the state which adjoins the said circumferential direction, and is provided with the protrusion part which protrudes to the radial direction outer side of the said injection pipe. Lubricating system for internal combustion engines. A baffle plate is attached to the head cover body from the back side,
A guide portion for guiding the lubricating oil scattered from the rotation transmitting member that rotates with the operation of the valve operating mechanism of the internal combustion engine to the injection port of the injection pipe is formed in a part of the baffle plate. The lubricating oil injection structure for an internal combustion engine according to any one of claims 1 to 4.   The lubricating oil injection structure for an internal combustion engine according to claim 5, wherein the guide portion is inclined so that a downstream portion in a direction in which the lubricating oil is scattered is closer to the injection pipe than an upstream portion.

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