JP6452671B2 - Lubrication structure of internal combustion engine - Google Patents

Description

  The present invention relates to a lubricating structure for an internal combustion engine.

  In an internal combustion engine, a projecting piece is provided on the lower surface of the head cover that defines the upper part of the chain case that houses the timing chain, and the upper end of the chain guide that slides on the timing chain is disposed below the projecting piece. There is a type of lubricating the timing chain by dropping the adhering lubricating oil from the protruding piece onto the upper end of the chain guide (for example, Patent Document 1).

Japanese Utility Model Publication No. 64-3764

  A rotation phase variable mechanism such as a valve timing variable mechanism that changes the rotation phase between the cam sprocket and the camshaft may be provided at the end of the camshaft. Many of the rotation phase variable mechanisms are driven by hydraulic pressure, and some of the hydraulic oil (lubricating oil) leaks to the outside and some of the hydraulic oil positively discharges to the outside. However, in the configuration in which the projecting piece is provided on the lower surface of the head cover corresponding to the side of the cam sprocket, there is a problem that the lubricating oil scattered from the rotational phase variable mechanism cannot be efficiently collected. Therefore, if the lubricating oil flowing out from the rotation phase variable mechanism can be collected efficiently, the amount of lubricating oil that can be supplied to the chain increases.

  In view of the above background, an object of the present invention is to increase the amount of lubricating oil that can be supplied to a chain in a lubricating structure that lubricates the chain by using scattered lubricating oil.

  In order to solve the above problems, an aspect of the present invention is a lubricating structure for an internal combustion engine, which includes a rotating shaft extending in the front-rear direction, a sprocket provided at a front end of the rotating shaft, and the sprocket wound around the rotating shaft. Rotation phase that is provided between the transmission mechanism including a chain and the sprocket and the rotation shaft, transmits the rotation by the sprocket and the rotation shaft, and can change the rotation phase of the sprocket and the rotation shaft by hydraulic pressure. A variable mechanism; a chain guide slidably in contact with the chain; an upper wall provided above the sprocket and the rotational phase variable mechanism; and a cover member having a guide wall suspended from the upper wall; The wall extends laterally from the front wall portion located in front of the rotational phase variable mechanism to the side wall portion located lateral to the sprocket. Mashimashi, lower edge of the side wall portion is characterized by having a tip which is located above the chain guide or the chain.

  According to this aspect, since the guide wall extends from the side of the rotational phase variable mechanism to the front, the lubricating oil that has flowed out and scattered from the rotational phase variable mechanism is collected on the guide wall. The lubricating oil collected on the guide wall falls from the protruding end provided at the lower edge of the side wall portion of the guide wall to the chain guide or the chain, and the sliding portion of the chain is lubricated. For example, a rotation phase variable mechanism such as a valve timing variable mechanism is driven by hydraulic pressure, so that a part of hydraulic oil (lubricating oil) leaks to the outside or a part of the hydraulic oil is positively discharged to the outside. There are things to do. Therefore, the amount of lubricating oil that can be supplied to the chain is increased by collecting the lubricating oil flowing out from the rotational phase variable mechanism with the guide wall.

  In the above aspect, the lower edge of the guide wall may be inclined downward toward the protruding end.

  According to this aspect, the lubricating oil collected on the guide wall can flow downward on the surface by gravity, and can be collected at the tip along the lower edge.

  In the above aspect, the side surface of the guide wall facing the rotational phase variable mechanism and the sprocket side may be curved from the front wall portion to the side wall portion.

  According to this aspect, the lubricating oil collected by the front wall part can flow smoothly to the side wall part.

  In the above aspect, the cover member may have an outer wall that hangs down from the upper wall and defines a part of the chain chamber, and the guide wall may be disposed inside the outer wall. .

  According to this aspect, since the guide wall is provided inside the outer wall that defines the chain chamber, the guide wall can be brought close to the rotation phase variable mechanism and the sprocket. As a result, the guide wall can reliably collect the lubricating oil scattered from the rotational phase variable mechanism and the sprocket.

  In the above aspect, the front wall portion of the guide wall may be formed integrally with the outer wall.

  According to this aspect, since a part of the outer wall portion also serves as a part of the guide wall, the cover member can be reduced in size.

  In the above aspect, the lower edge of the front wall portion of the guide wall may be convex or concave with respect to the outer wall, and may be inclined downward toward the side wall portion.

  According to this aspect, the lubricating oil collected on the front wall portion of the upper wall and the guide wall flows downward on the surface of the front wall portion due to gravity, and travels along the lower edge of the front wall portion to the side wall portion side. Can flow.

  In the above aspect, the side wall portion of the guide wall is disposed with a gap with respect to the inner surface of the outer wall, and is coupled to the outer wall by a reinforcing wall extending in the left-right direction. The edge may be inclined so that the side wall portion side is positioned below the outer wall side.

  According to this aspect, the guide wall can be brought close to the side portion of the sprocket. Further, the rigidity of the guide wall is enhanced by the reinforcing wall. The lubricating oil collected on the outer wall and the reinforcing wall is collected on the side wall portion of the guide wall along the lower edge of the reinforcing wall.

  In the above aspect, the rotational phase variable mechanism may have an oil discharge hole opened in a front surface thereof.

  According to this aspect, the lubricating oil discharged from the oil discharge hole is scattered forward and radially from the oil discharge hole, and a part is collected on the upper wall. The lubricating oil collected on the upper wall flows downward on the surface of the front wall portion of the guide wall by gravity, flows to the side wall portion side along the lower edge of the front wall portion, and is collected at the tip.

  Further, in the above aspect, the rotation phase variable mechanism is configured to rotate integrally with the first rotating part that rotates integrally with the sprocket and the rotating shaft, and define an oil chamber between the first rotating part. A second rotating part, a lock pin hole formed at a position where the first rotating part and the second rotating part face each other, and both the first rotating part and the second rotating part in the lock pin hole. A lock pin that is received so as to be displaceable between a lock position that engages with the first rotation portion and a release position that engages with only one of the first rotation portion and the second rotation portion, and an oil supply that is connected to the lock pin hole. The oil discharge hole may be connected to the lock pin hole.

  According to this aspect, the front wall portion of the guide wall can collect the lubricating oil flowing out from the lock pin hole of the rotational phase variable mechanism.

  In the above aspect, it is preferable that the upper end portion of the chain guide protrudes to the side of the sprocket when viewed in the vertical direction, and the protruding end is disposed above the upper end portion of the chain guide.

  According to this aspect, the lubricating oil falls from the protruding end of the guide wall to the upper end portion of the chain guide, and flows from the upper end portion to the sliding contact portion with the chain.

  According to the above configuration, the amount of lubricating oil that can be supplied to the chain can be increased in the lubricating structure that lubricates the chain using the scattered lubricating oil.

A longitudinal sectional view of an internal combustion engine according to an embodiment Perspective view of the head cover as seen from below III-III sectional view of FIG. Explanatory drawing which shows the positional relationship of the valve timing variable mechanism and guide wall seen from the front Schematic diagram of variable valve timing mechanism Sectional view showing the positional relationship between the variable valve timing mechanism and the guide wall (cross-sectional view taken along the line VI-VI in FIG. 1) Perspective view of the upper end of the chain guide

  Hereinafter, an internal combustion engine to which a lubricating structure for an internal combustion engine according to the present invention is applied will be described with reference to the drawings. In the following description, the axial direction of the crankshaft is defined as the front-rear direction, the vertical vertical direction is defined as the vertical direction, and the direction orthogonal to the front-rear direction and the vertical direction is defined as the left-right direction. Further, the internal combustion engine is described in a posture in use. In addition, the front-back direction and the left-right direction are for convenience of explanation, and do not limit the relationship with the traveling direction of the vehicle on which the internal combustion engine is mounted.

  As shown in FIG. 1, an internal combustion engine 1 is coupled to a cylinder block 2 in which a plurality of cylinders and a crank chamber are formed, a cylinder head 3 coupled to an upper portion of the cylinder block 2, and a lower end portion of the cylinder block 2. And an oil pan 4, a head cover 5 (cover member) coupled to the upper end of the cylinder head 3, and a chain case 6 coupled to the cylinder block 2 and the cylinder head 3. A crankshaft 7 extending in the front-rear direction is rotatably supported in the crank chamber of the cylinder block 2.

  The oil pan 4 is formed in a box shape opened upward, and a front end portion of the oil pan 4 extends forward from a block front wall 2 </ b> A that is a front end wall of the cylinder block 2. The head cover 5 is formed in a box shape that opens downward, and its front end extends forward from the head front wall 3 </ b> A that is the front end wall of the cylinder head 3. The chain case 6 protrudes rearward from each of the case front wall 6A (see FIG. 3) whose main surface faces in the front-rear direction and extends in the vertical direction (see FIG. 3), and the left and right side edges of the case front wall 6A. And a case edge wall 6B extending in the vertical direction. The chain case 6 is coupled to the block front wall 2A and the head front wall 3A at the left and right case edge walls 6B, is coupled to the front part of the oil pan 4 at the lower edge, and is coupled to the front part of the head cover 5 at the upper edge. . The space extending in the vertical direction between the chain case 6 and the block front wall 2A and the head front wall 3A, the front end portion inside the oil pan 4, and the front end portion inside the head cover 5 extend in the vertical direction in cooperation. A chain chamber 10 is defined.

  A valve operating chamber 11 is formed between the upper surface of the cylinder head 3 and the head cover 5. The valve operating chamber 11 has an intake camshaft 13 (rotary shaft) and an exhaust camshaft for opening and closing an intake valve and an exhaust valve. 14 is provided. The intake camshaft 13 and the exhaust camshaft 14 extend in the front-rear direction and are rotatably supported by bearings provided at the upper part of the cylinder head 3. The front ends of the intake camshaft 13 and the exhaust camshaft 14 are arranged between the head front wall 3A and the front end portion of the head cover 5, that is, at the upper end portion of the chain chamber 10. The intake camshaft 13 is disposed on the right side with respect to the exhaust camshaft 14. The internal combustion engine 1 is inclined to the left so that the intake camshaft 13 side is positioned above the exhaust camshaft 14 side. That is, the cylinder axis of the internal combustion engine 1 is inclined to the left. The inclination angle of the internal combustion engine 1 may be about 5 °, for example.

  The front end of the crankshaft 7 penetrates the block front wall 2A and the chain case 6 and projects forward of the case front wall 6A. A crank sprocket 16 is coupled to a portion of the crankshaft 7 located in the chain chamber 10. An intake sprocket 18 is provided at the front end of the intake camshaft 13 via a variable valve timing mechanism 17 (rotational phase variable mechanism), and an exhaust sprocket 19 is coupled to the front end of the exhaust camshaft 14. The crank sprocket 16, the intake sprocket 18, and the exhaust sprocket 19 are rotatable about axes extending in the front-rear direction, and a chain 20 is wound thereon. The crank sprocket 16, the intake sprocket 18, the exhaust sprocket 19, and the chain 20 constitute a power transmission mechanism 22 that transmits the rotational force of the crankshaft 7 to the intake camshaft 13 and the exhaust camshaft 14. The chain 20 may be a silent chain or a roller chain. The crank sprocket 16, the chain 20, the intake sprocket 18, the variable valve timing mechanism 17, and the exhaust sprocket 19 rotate clockwise as viewed from the front as shown in FIG.

  The variable valve timing mechanism 17 transmits the rotation of the intake sprocket 18 to the intake camshaft 13 and enables the rotation phase of the intake sprocket 18 and the intake camshaft 13 to be changed by hydraulic pressure. As shown in FIG. 5 and FIG. 6, the variable valve timing mechanism 17 is integrally formed with the housing 31 (first rotating portion) that is rotatably supported on the front end of the intake camshaft 13 and the front end of the intake camshaft 13. A vane 32 (second rotating portion) is rotatably coupled and received in the housing 31. The housing 31 has a cylindrical shape, and includes a housing main body 34 disposed coaxially with the intake camshaft 13, and a front plate 35 and a rear plate 36 provided at the front end and the rear end of the housing main body 34. The housing body 34, the front plate 35, and the rear plate 36 are fastened to each other by bolts 37. The rear plate 36 is a member common to the intake sprocket 18, and a tooth portion 18 </ b> A of the intake sprocket 18 is formed on the outer peripheral portion of the rear plate 36. A through hole 38 through which the intake camshaft 13 passes is formed at the center of the rear plate 36. An opening 39 that is a circular through hole is formed at the center of the front plate 35. A plurality of recesses 41 are formed on the inner peripheral surface of the housing main body 34 so as to be recessed outward in the radial direction and having a predetermined width in the circumferential direction.

  The vane 32 protrudes radially outward from the outer periphery of the shaft portion 32 </ b> A and is fastened to the front end surface of the intake camshaft 13 by a bolt 42 and enters the recess 41. And a plurality of wing portions 32B. The wing portion 32B partitions the concave portion 41 into an advance oil chamber 41A and a retard oil chamber 41B in the circumferential direction. When the vane 32 rotates relative to the housing 31, the volumes of the advance oil chamber 41A and the retard oil chamber 41B change. The head of the bolt 42 passes through the opening 39 and projects forward of the front plate 35. The variable valve timing mechanism 17 is fastened to the intake camshaft 13 by fastening the vane 32 to the intake camshaft 13 by a single bolt 42 arranged on the axis of the housing 31.

  A vane side pin hole 45 penetrating in the front-rear direction is formed in one of the wing portions 32B. A bottomed housing side pin hole 46 is recessed in a portion of the rear plate 36 facing the vane side pin hole 45 in the most retarded state where the volume of the advance oil chamber 41A is minimized. A lock pin 47 that can be fitted into the housing side pin hole 46 is slidably accommodated in the vane side pin hole 45. The lock pin 47 is biased by a spring 48 that is a compression coil spring provided between the lock plate 47 and the front plate 35. In an initial state, the lock pin 47 is locked at a position where the rear end of the lock pin 47 is fitted into the housing side pin hole 46. It is in. An oil discharge groove 49 is formed in the front surface of the vane 32 so as to extend in the radial direction from the front end of the vane side pin hole 45 toward the axial line side of the vane 32 and to the opening 39 of the front plate 35.

  The cylinder head 3 is formed with a head side advance oil passage 51 and a head side retard oil passage 52 that extend to the bearing portion of the intake camshaft 13. The head side advance oil passage 51 and the head side retard oil passage 52 are connected to an oil pump (not shown), which is a hydraulic power source, via a hydraulic control valve (not shown). The head side advance oil passage 51 is connected to the advance oil chamber 41 </ b> A via a cam side advance oil passage 53 formed in the intake camshaft 13 and a vane side advance oil passage 54 formed in the vane 32. ing. The head side retard oil passage 52 is connected to the retard oil chamber 41 </ b> B via a cam side retard oil passage 56 formed in the intake camshaft 13 and a vane side retard oil passage 57 formed in the vane 32. ing. The housing side pin hole 46 is connected to the advance angle oil chamber 41 </ b> A via an advance angle chamber connection oil passage 58 formed in the rear plate 36, and via a retard angle chamber connection oil passage 59 formed in the rear plate 36. The retard oil chamber 41B is connected.

  When the hydraulic control valve connects the head side advance oil passage 51 to the oil pump and connects the head side retard oil passage 52 to the drain, the hydraulic pressure is supplied to the advance oil chamber 41A and the housing side pin hole 46, so that Hydraulic pressure is discharged from the corner oil chamber 41B. As a result, the lock pin 47 moves to the release position where the lock pin 47 is detached from the housing side pin hole 46, the vane 32 can rotate with respect to the housing 31, the volume of the advance oil chamber 41 </ b> A increases, The vane 32 advances. When the hydraulic control valve connects the head-side retarded oil passage 52 to the oil pump and the head-side advanced oil passage 51 to the drain, the hydraulic pressure is supplied to the retarded oil chamber 41B and the housing-side pin hole 46, and the hydraulic control valve advances. Hydraulic pressure is discharged from the corner oil chamber 41A. As a result, the volume of the retard oil chamber 41 </ b> B increases and the vane 32 retards relative to the housing 31. When hydraulic pressure is supplied to the advance oil chamber 41A or the retard oil chamber 41B, the hydraulic pressure is supplied to the housing side pin hole 46, and the lock pin 47 moves to the release position. A portion of the lubricating oil supplied to the housing side pin hole 46 passes through the vane side pin hole 45 and the oil discharge groove 49, and a gap between an opening 39 formed at the center of the front surface of the housing 31 and the bolt 42. To be discharged. That is, the variable valve timing mechanism 17 always discharges the lubricating oil from the opening 39 to the outside in the driving state of the internal combustion engine 1.

  Since the rear plate 36 that forms the rear end of the housing 31 constitutes the intake sprocket 18, the variable valve timing mechanism 17 is provided on the front side of the intake sprocket 18. The intake sprocket 18, the variable valve timing mechanism 17, and the intake camshaft 13 are arranged coaxially with each other, and the intake camshaft 13 extends rearward from the intake sprocket 18.

  As shown in FIG. 1, a chain tensioner 60 and a first chain guide 61 are provided on the block front wall 2 </ b> A and the head front wall 3 </ b> A, and a second chain guide 62 is provided on the cylinder head 3. The chain tensioner 60 is in sliding contact with the chain 20 between the crank sprocket 16 and the intake sprocket 18, the first chain guide 61 is in sliding contact with the chain 20 between the exhaust sprocket 19 and the crank sprocket 16, and the second chain guide 62 is in contact with the intake sprocket 18 and It is in sliding contact with the chain 20 between the exhaust sprockets 19.

  The chain tensioner 60 includes a base 64 extending in the vertical direction and a plate-like shoe 65 supported on the side surface of the base 64 on the chain 20 side. The base 64 is supported by the head front wall 3A so as to be rotatable about an axis extending in the front-rear direction at a pivot portion 66 provided at the upper end portion 64A, and is urged by a lower end portion 64B supported by the block front wall 2A. 63 is energized. The urging device 63 includes a spring inside and urges the lower end of the base 64 toward the chain 20.

  As shown in FIGS. 3, 6, and 7, the base 64 is disposed at the same position as the crank sprocket 16 and the intake sprocket 18 in the front-rear direction. The base 64 has an arc portion 64C that is curved in an arc shape that protrudes toward the chain 20 between the upper end portion 64A and the lower end portion 64B. The side surface of the upper end portion 64A on the chain 20 side is inclined to the side away from the chain 20 (rightward) with respect to the side surface of the arc portion 64C on the chain 20 side. The side surface of the upper end portion 64A on the chain 20 side extends to the left and right above the pivot portion 66, and protrudes to the right from the right end portion of the outer periphery of the intake sprocket 18 when viewed in the vertical direction. An oil groove 67 extending in a vertical direction from the upper end portion 64A is recessed in a central portion in the width direction (front-rear direction) of the side surface of the base 64 on the chain 20 side. A pair of edge walls 68 extending along the extending direction of the upper end portion 64 </ b> A project from both side edges of the side surface on the chain 20 side of the upper end portion 64 </ b> A of the base 64. Due to the pair of edge walls 68, the chain side of the upper end portion 64A has a groove-shaped cross section. The pair of edge walls 68 gradually decrease in protruding height so that the protruding height becomes zero at the lower end of the upper end portion 64A.

  The shoe 65 is disposed on the side surface of the base 64 on the side of the chain 20 excluding the upper end portion 64A. Edge walls 65 </ b> A extending in the extending direction of the shoe 65 protrude from both side edges of the shoe 65. The edge wall 65A is engaged with both side portions of the chain 20 to prevent the position shift of the chain 20 with respect to the shoe 65. The chain tensioner 60 is in sliding contact with the chain 20 at the shoe 65, and the base 64 is not in sliding contact with the chain 20. In the center of the surface of the shoe 65 in the width direction (front-rear direction), an oil groove 65B extending in the up-down direction from the upper end to the lower end is recessed. The oil groove 67 of the base 64 extends from the upper end portion 64 </ b> A to a position corresponding to the back surface of the upper end portion of the shoe 65.

  As shown in FIGS. 1 and 2, the head cover 5 is suspended from an upper wall 71 that extends in the front-rear direction so as to face the upper portion of the cylinder head 3, and a front edge, a left and right side edge, and a rear edge of the upper wall 71. It has a front outer wall 72, a left outer wall 73, a right outer wall 74, and a rear outer wall (not shown), and has a box shape opened downward. The front outer wall 72 is disposed with a gap in front of the variable valve timing mechanism 17 and the exhaust sprocket 19.

  FIG. 4 is an explanatory view showing the configuration of the head cover 5 excluding the guide wall 76 as seen through. As shown in FIGS. 2 to 4, a guide wall 76 that hangs down is provided on the lower surface of the upper wall 71. The guide wall 76 extends in the lateral direction (left-right direction) from the front wall portion 77 located in front of the variable valve timing mechanism 17 to the side wall portion 78 located on the right side of the intake sprocket 18. The front wall 77 has a surface that faces substantially in the front-rear direction and extends left and right. The side wall portion 78 has a substantially horizontal surface and extends in the front-rear direction. The guide wall 76 extends from the front wall portion 77 to the side wall portion 78 while being smoothly curved. That is, the boundary portion between the front wall portion 77 and the side wall portion 78 is formed into a smooth curved surface, and the inner side surface 76A of the guide wall 76 that is the surface of the front wall portion 77 and the side wall portion 78 on the valve timing variable mechanism 17 side is smooth. A continuous surface is formed.

  As shown in FIG. 6, in this embodiment, the front wall portion 77 is integrally formed on the inner side surface of the front outer wall 72. The side wall portion 78 projects rearward from the inner side surface of the front outer wall 72 at the boundary with the front wall portion 77 and is disposed on the inner side (right side) of the right outer wall 74 via a gap. The side wall portion 78 and the right outer wall 74 are coupled to each other by a reinforcing wall 79 extending in the left-right direction. The lower edge 79A of the reinforcing wall 79 is inclined so that the side wall 78 side is positioned below the right outer wall 74 side.

  As shown in FIG. 2, the lower edge 77 </ b> A of the front wall portion 77 forms a stepped portion that protrudes backward with respect to the inner surface of the front outer wall 72. That is, the surface (rear surface) of the front wall portion 77 is disposed on the inner surface of the front outer wall 72 so as to be offset rearward. In another embodiment, the lower edge 77 </ b> A of the front wall portion 77 may form a step portion that is concave forward with respect to the inner surface of the front outer wall 72. In other words, the front surface (rear surface) of the front wall portion 77 may be disposed to be offset forward from the inner surface of the front outer wall 72.

  The lower edge 77A of the front wall portion 77 is inclined such that the side wall portion 78 side (right side) is positioned below the side (left side) opposite to the side wall portion 78 side. The end of the lower edge 77 </ b> A of the front wall 77 opposite to the side wall 78 side extends in the left-right direction from the rotation center of the valve timing variable mechanism 17 and is connected to the upper wall 71. The end of the lower edge 77 </ b> A of the front wall 77 on the side wall 78 side is connected to the lower edge 78 </ b> A of the side wall 78.

  As shown in FIG. 4, the guide wall 76 including the front wall portion 77 and the side wall portion 78 is disposed so as not to overlap the housing 31 of the variable valve timing mechanism 17 when viewed from the direction along the front-rear direction. Thereby, the housing 31 and the front outer wall 72 can be brought close to each other in the front-rear direction while avoiding interference between the front wall portion 77 and the housing 31. Further, when viewed from the direction along the front-rear direction, the lower edge 77A of the front wall 77 extends to the left and right while inclining above the center of the valve timing variable mechanism 17. Further, when viewed from the direction along the vertical direction, the front wall 77 is curved so as to protrude forward, and the end of the front wall 77 on the side wall 78 side is the front plate 35 of the variable valve timing mechanism 17. It extends behind the front of the.

  As shown in FIG. 6, the side wall portion 78 is disposed so as to overlap with, specifically intersect with, the upper end portion 64 </ b> A of the base 64 of the chain tensioner 60 as viewed from above. The lower edge 78A of the side wall portion 78 includes a protrusion 78B positioned at the lowermost part in the front-rear direction, and is inclined toward the protrusion 78B. The protruding end 78 </ b> B is disposed immediately above the upper end portion 64 </ b> A of the base 64. That is, the projecting end 78 </ b> B is disposed at a portion where the side wall 78 intersects the upper end 64 </ b> A of the base 64 as viewed from above. Further, the protrusion 78B is disposed on the side of the tooth portion 18A of the intake sprocket 18 when viewed from above. The end portion on the front wall portion 77 side of the lower edge 78A of the side wall portion 78 is connected to the end portion on the side wall portion 78 side of the lower edge 77A. The inclination angle of the lower edge 77A of the front wall 77 with respect to the horizontal plane is set smaller than the inclination angle of the lower edge 78A of the side wall 78 with respect to the horizontal plane. Thereby, the extension length in the left-right direction of the front wall portion 77 can be set longer than the extension length in the left-right direction of the side wall portion 78. Further, since the inclination angle of the lower edge 77A of the front wall 77 with respect to the horizontal plane is set smaller than the inclination angle of the lower edge 78A of the side wall 78 with respect to the horizontal plane, the front wall 77 avoids interference with the housing 31. However, it can extend to the left and right, and the lubricating oil scattered from the variable valve timing mechanism 17 can be collected over a wide range.

  As shown in FIG. 1, the projecting end 78 </ b> B of the side wall portion 78 is disposed below the rotation center of the intake sprocket 18. It is preferable that the projecting end 78B of the side wall portion 78 is disposed on the side of the position where the intake sprocket 18 and the chain 20 start to bite.

  As shown in FIGS. 1 and 3, an oil guide 81 is provided on the rear surface (the surface on the chain chamber 10 side) of the case front wall 6 </ b> A of the chain case 6. The oil guide 81 protrudes rearward from the rear surface of the case front wall 6A, and has a protrusion 81A extending left and right below the intake sprocket 18, and a protrusion piece 81B protruding further rearward from the left end of the protrusion 81A. . The protrusion 81 </ b> A extends to the left and right with a gap from the chain tensioner 60 in front of the chain tensioner 60, and the left end thereof is positioned to the left of the chain 20 that contacts the chain tensioner 60. The protrusion 81A is inclined with respect to the horizontal plane so that the left end side is positioned below the right end side. The front end (rear end) of the projecting piece portion 81 </ b> B is located above the chain 20. The projecting piece portion 81B is inclined with respect to the horizontal plane so that the distal end side is positioned below the proximal end side.

  The operation of the internal combustion engine 1 configured as described above will be described. As shown in FIG. 1, when the internal combustion engine 1 is driven, the crankshaft 7 rotates, the intake sprocket 18 and the exhaust sprocket 19 connected by the crank sprocket 16 and the chain 20 rotate, and the rotational phase with respect to the intake sprocket 18. The variable valve timing mechanism 17 that can be changed is rotated.

  The variable valve timing mechanism 17 discharges the lubricating oil to the outside through a gap between the opening 39 and the bolt 42 formed in the front surface in a specific operation state. In the present embodiment, the variable valve timing mechanism 17 supplies the lubricating oil supplied to the housing side pin hole 46 in the driving state of the internal combustion engine 1 through the vane side pin hole 45 and the oil discharge groove 49 and the bolts 42. To the outside through the gap. Since the lubricating oil discharged from the gap between the opening 39 and the bolt 42 has a relatively high pressure, a part of the lubricating oil is ejected forward from the opening 39 and adheres to the front outer wall 72 and flows downward. Further, a part of the lubricating oil flowing forward from the gap between the opening 39 and the bolt 42 is scattered in the radial direction due to the centrifugal force caused by the rotation of the valve timing variable mechanism 17, and the oil scattered upward is the upper wall 71. Those attached to the right side and scattered to the right side adhere to the side wall portion 78 of the guide wall 76 or the side wall portion side portion of the front wall portion 77. Part of the lubricating oil adhering to the upper wall 71 flows to the front wall portion 77 and the side wall portion 78 of the guide wall 76 due to gravity or being pushed by the lubricating oil scattered one after another.

  The lubricating oil adhering to the front wall 77 flows downward due to gravity and reaches the lower edge 77A of the front wall 77. The lubricating oil that has reached the lower edge 77A flows to the side wall portion 78 along the lower edge 77A that protrudes with respect to the outer front side wall. Specifically, the lubricating oil that adheres (wet) to the lower edge 77A maintains the adhesion to the lower edge 77A, so that the lubricating oil flows along the convex shape of the lower edge 77A. The lubricating oil adhering to the side wall portion 78 flows to the lower edge 78A by gravity and is collected along the lower edge 78A at the projecting end 78B located at the lowermost end.

  Further, in the intake sprocket 18, centrifugal force is generated by the rotation, and the lubricating oil adhering to the intake sprocket 18 and the chain 20 wound around the intake sprocket 18 is scattered in the radial direction of the intake sprocket 18. In particular, the scattering of the lubricating oil increases in a range where the intake sprocket 18 and the chain 20 are engaged with each other. In the present embodiment, the amount of scattered lubricant increases in the range from the right end to the upper end of the intake sprocket. This is due to the fact that the lubricating oil adhering to the chain starts to scatter due to centrifugal force when it begins to bite with the intake sprocket. Lubricating oil scattered from the intake sprocket and the chain 20 adheres to the side wall portion 78 and the upper wall 71 of the guide wall 76. Part of the lubricating oil adhering to the upper wall 71 flows to the front wall portion 77 and the side wall portion 78 of the guide wall 76 and is collected at the projecting end 78B by the lower edge 77A and the lower edge 78A. The guide wall 76 extends from the right to the front of the intake sprocket 18 and the variable valve timing mechanism 17 in order to collect the lubricating oil scattered from the intake sprocket 18 and the variable valve timing mechanism 17. The valve timing variable mechanism 17 extends from the upper right to the front upper.

  Also, the lubricating oil adhering to the right outer wall 74 and the reinforcing wall 79 due to the spraying or splashing of the lubricating oil flows along the lower edge 79A of the reinforcing wall 79 by gravity and flows to the side wall portion 78 of the guide wall 76, and the side wall portion 78. Is collected at the tip 78B along the surface and the lower edge 78A.

  The lubricating oil collected at the protrusion 78B falls from the protrusion 78B and is supplied to the upper end portion 64A of the base 64 of the chain tensioner 60. Thus, the upper end portion 64A functions as an oil receiving portion that receives the lubricating oil falling from the protruding end 78B.

  A part of the lubricating oil supplied to the upper end portion 64A of the base 64 flows along the oil groove 67 between the side surface on the chain side of the base 64 and the back surface of the shoe 65, and cools the shoe 65 and the base 64. The other part flows on the surface of the shoe 65 and lubricates the sliding contact portion between the shoe 65 and the chain 20. A portion of the lubricating oil that has flowed to the surface of the shoe 65 flows downward along the oil groove 65B, and the other portion adheres to the chain 20 and is carried away. The lubricating oil adhering to the chain 20 lubricates the contact portion between the intake sprocket 18 and the exhaust sprocket 19 located on the downstream side.

  In the internal combustion engine 1 according to this embodiment, the guide wall 76 and the upper wall 71 of the head cover 5 collect the lubricating oil scattered from the intake sprocket 18 and the valve timing variable mechanism 17, and the lubricating oil from the guide wall 76 to the chain tensioner 60. Can be supplied. Since the guide wall 76 extends from the side of the variable valve timing mechanism 17 to the front, it can collect the lubricating oil that has flowed out of the variable valve timing mechanism 17 and scattered. Therefore, the amount of lubricating oil that can be supplied to the chain tensioner 60 increases.

  Since the guide wall 76 is curved and the front wall 77 and the side wall 78 are smoothly connected, the lubricating oil adhering to the front wall 77 can move to the side wall 78. Further, since the lower edge 77A for guiding the adhering lubricating oil to the side wall 78 is formed on the front wall 77, the lubricating oil flowing out from the variable valve timing mechanism 17 is collected by the front wall 77. Can flow to the side wall portion 78. Since the lubricating oil adhering to the lower edge 77A maintains the adhering state to the lower edge 77A due to wetting, the lubricating oil can flow toward the side wall 78 along the lower edge 77A formed on the convex stepped portion.

  Since the variable valve timing mechanism 17 is provided on the intake sprocket 18, a load resulting from the phase change of the variable valve timing mechanism 17 is applied to the chain 20 and provided upstream of the intake sprocket 18 in the flow direction of the chain 20. Friction between the chain tensioner 60 and the chain 20 is likely to occur. In the present embodiment, since the lubricating oil scattered from the variable valve timing mechanism 17 and the intake sprocket 18 is collected by the guide wall 76 and actively supplied to the chain tensioner 60, the friction between the chain tensioner 60 and the chain 20 is reduced. Is done.

  Most of the lubricating oil splashed directly from the variable valve timing mechanism 17 to the front outer wall 72 and the lubricating oil flowing from the upper wall 71 to the front outer wall 72 flow downward on the surface of the front outer wall 72 due to gravity. Subsequently, the oil flows downward on the rear surface of the case front wall 6 </ b> A of the chain case 6 and reaches the oil guide 81. Thereafter, the lubricating oil flows to the left end side along the inclined protrusion 81A of the oil guide 81 and falls onto the chain 20 from the tip of the inclined protrusion 81B to lubricate the chain 20.

  Although the description of the specific embodiment is finished as described above, the present invention is not limited to the above embodiment and can be widely modified. For example, the form of the lower edge 77 </ b> A is not limited to a stepped portion, but can be various uneven shapes such as a protrusion such as a rib or a groove. Further, the front wall portion 77 of the guide wall 76 facing the variable valve timing mechanism 17 does not need to be orthogonal to the rotation axis of the variable valve timing mechanism 17 and may be inclined. For example, if the inner side surface of the front wall portion 77 is inclined rearward toward the side wall portion 78 side, it can be smoothly connected to the side wall portion 78.

  It is not essential that the front wall portion 77 overlaps the variable valve timing mechanism 17 in the front-rear direction when viewed from the vertical direction. Similarly, the side wall portion 78 overlaps the variable valve timing mechanism 17 in the left-right direction. Is not a required configuration. The front wall portion 77 and the side wall portion 78 may be disposed on the front and side where the lubricating oil scatters from the valve timing variable mechanism 17.

  The above embodiment is an example in which the crank sprocket 16 is applied to the driving sprocket and the intake sprocket 18 is applied to the driven sprocket. However, various other sprockets can be applied to the driving sprocket and the driven sprocket. For example, the drive sprocket may be another sprocket that rotates by receiving the rotational force of the crankshaft 7, and the driven sprocket may be the exhaust sprocket 19 or another idler sprocket. The rotation phase variable mechanism is not limited to the one that changes the rotation phase between the intake sprocket 18 and the intake camshaft 13, but the one that changes the rotation phase between the exhaust sprocket 19 and the exhaust camshaft 14, or two different sprockets. The rotation phase between them may be changed.

  Further, the supply destination of the lubricating oil falling from the protrusion 78B is not limited to the chain tensioner 60, and may be the chain 20 or another chain guide. In this case, the projecting end 78B may be disposed above the chain 20 or other chain guide.

1: Internal combustion engine 13: Intake camshaft (rotary shaft)
16: Crank sprocket 17: Variable valve timing mechanism (variable rotation phase mechanism)
18: Intake sprocket 19: Exhaust sprocket 20: Chain 22: Power transmission mechanism 31: Housing (first rotating portion)
32: Vane (second rotating part)
39: Opening (oil discharge hole)
45: Vane side pin hole (lock pin hole)
46: Housing side pin hole (lock pin hole)
47: Lock pin 49: Oil discharge groove 60: Chain tensioner (chain guide)
64: base 64A: upper end 71: upper wall 72: front outer wall 73: left outer wall 74: right outer wall 76: right outer wall 76: guide wall 77: front wall 77A: lower edge 78: side wall 78A: lower edge 78B: protruding end 79: Reinforcing wall

Claims (8)

A lubricating structure for an internal combustion engine,
A rotating shaft extending in the front-rear direction;
A transmission mechanism including a sprocket provided at a front end of the rotating shaft, and a chain wound around the sprocket;
A rotation phase variable mechanism that is provided between the sprocket and the rotation shaft, transmits rotation by the sprocket and the rotation shaft, and can change a rotation phase between the sprocket and the rotation shaft by hydraulic pressure;
A chain guide in sliding contact with the chain;
An upper wall provided above the sprocket and the rotational phase variable mechanism, and a guide that hangs down from the upper wall , collects lubricating oil scattered from the rotational phase variable mechanism and the sprocket, and supplies the lubricating oil to the chain guide A cover member having a wall,
The guide wall extends while curving from a front wall portion located in front of the rotational phase variable mechanism to a side wall portion located on the side of the sprocket, and a lower edge of the side wall portion is located above the chain guide. have a tip located, lubrication structure for an internal combustion engine, characterized in that said lower edge of the front wall portion and the lower edge of the side wall portion which is inclined downwardly to connect with each other, and towards the headland . The cover member has an outer wall depending from the upper wall and defining a portion of the chain chamber;
The lubricating structure for an internal combustion engine according to claim 1 , wherein the guide wall is disposed inside the outer wall. The lubricating structure for an internal combustion engine according to claim 2 , wherein the front wall portion of the guide wall is formed integrally with the outer wall. 4. The internal combustion engine according to claim 3 , wherein a lower edge of the front wall portion of the guide wall is convex or concave with respect to the outer wall, and extends downwardly inclined toward the side wall portion. The lubrication structure of the engine. The side wall portion of the guide wall is disposed with a gap with respect to the inner surface of the outer wall, and is coupled to the outer wall by a reinforcing wall extending in the left-right direction, and a lower edge of the reinforcing wall is on the outer wall side. The lubricating structure for an internal combustion engine according to any one of claims 2 to 4 , wherein the side wall portion side is inclined with respect to the lower side. The lubrication structure for an internal combustion engine according to any one of claims 1 to 5 , wherein the rotation phase variable mechanism has an oil discharge hole opened in a front surface thereof. The rotation phase variable mechanism includes: a first rotating part that rotates integrally with the sprocket; a second rotating part that rotates integrally with the rotating shaft and defines an oil chamber between the first rotating part; A lock pin hole formed at a position of the first rotation part and the second rotation part facing each other; a lock position engaging with both the first rotation part and the second rotation part in the lock pin hole; A lock pin that is displaceably received between a release position engaged with only one of the first rotating part and the second rotating part, and an oil supply path connected to the lock pin hole,
The lubricating structure for an internal combustion engine according to claim 6 , wherein the oil discharge hole is connected to the lock pin hole. The upper end portion of the chain guide protrudes to the side of the sprocket as seen from the vertical direction,
The lubricating structure for an internal combustion engine according to any one of claims 1 to 7 , wherein the protruding end is disposed above an upper end portion of the chain guide.

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