JP6078446B2 - Cam bearing lubrication structure for internal combustion engine - Google Patents

Description

  The present invention relates to an oil supply structure for a camshaft of a valve mechanism of an internal combustion engine.

  As a supply path for lubricating oil to a camshaft provided with intake and exhaust cams for opening and closing intake and exhaust valves in a valve mechanism of an internal combustion engine, these camshafts are parallel to the intake camshaft and exhaust camshaft in the cylinder head. The main lubricating oil passage to which lubricating oil is supplied from the oil pump is formed. Since the main lubricating oil passage is disposed between the intake camshaft and the exhaust camshaft, a plug hole is formed between the intake camshaft and the exhaust camshaft. The main lubricating oil passage is divided by crossing the main lubricating oil passage. Therefore, an annular cylinder member is inserted into the plug hole, and an oil passage that bypasses the outer periphery of the plug cylinder is formed by mounting in a liquid-tight manner with the plug hole above and below the main lubricating oil passage. The main lubricating oil passage is connected.

  Further, the main lubricating oil passage is provided with a guide passage extending in the vertical direction toward the bearing portion located at the shaft end of the camshaft via the connecting passage and the extension passage on the downstream side to lubricate the bearing portion. ing. By the way, at least a plurality of such bearing portions of the camshaft are provided. When oil passages such as communication passages, extension passages, and guide passages that are independently formed are provided in each bearing portion, Cam bearing oil supply structure for internal combustion engines that can be easily machined while shortening the oil passage to each part, because it is necessary to secure the arrangement space and consider the workability to the cylinder head, which may increase the size of the cylinder head Has been desired (see Prior Art Document 1).

Japanese Patent No. 3198689

  The present invention solves such problems of the prior art, and an object of the present invention is to prevent an increase in the space of the oil passage and to reduce the size of the cylinder head, thereby reducing the size of the internal combustion engine. The present invention provides a cam bearing oil supply structure that is easy to process while reducing the oil passage to the shaft bearing and reduces the manufacturing cost.

In order to achieve the object, the invention according to claim 1 is a cylinder head having a bearing portion that slidably supports a camshaft, and is supported by the cylinder head so that the tip faces the combustion chamber. A plug hole for storing the spark plug to be formed, and a cylindrical shape, and is inserted into the plug hole in a liquid-tight manner at the upper and lower ends, thereby partitioning the inside of the cylinder head and the plug hole in the cam bearing lubrication structure with a plug tube is liquid-tightly at the upper and lower end of the plug tube and the plug hole, an outer peripheral oil passage which bypasses along the outer peripheral surface of the plug tube, the cylinder head A main lubricating oil passage formed so as to pass through the plug hole and connected by the outer peripheral oil passage, and the cam bearing so as to connect a sliding surface of the cam bearing portion from the outer peripheral oil passage. formed through the parts Is, the cam bearing portion and with a guide passage for supplying lubricating oil reaches the sliding surface of said cam shaft, an outlet port to the cam bearing portions of the guide passage, with respect to the rotation center of the cam shaft Provided on the semi-circumferential surface on the plug hole side, the cam bearing portion is composed of a plurality of divided halves, and is used as a fastening member for connecting them, and between the cam shaft and the plug hole A cam bearing oil supply structure for an internal combustion engine , wherein a screw hole provided in the internal combustion engine is formed so as to penetrate the guide passage, and the screw hole is sealed by the fastening member .

According to a second aspect of the present invention, the cam bearing portion (38) is divided into upper and lower half bodies (38a, 38b), and the guide passage (64) is formed on the upper and lower half bodies (38a, 38b). 2. The cam bearing oil supply structure for an internal combustion engine according to claim 1, wherein the cam bearing oil supply structure is formed so as to be inclined with respect to the joint surface (59) toward the plug hole (24) . 3.

According to a third aspect of the present invention, the cylinder head (4) is provided with a plurality of cam shafts (32, 33) sandwiching the plug hole (24), and the guides are respectively provided to the cam bearing portions (38). The cam bearing oil supply structure for an internal combustion engine according to claim 1 or 2, wherein a pair of passages (64) are formed .

According to a fourth aspect of the present invention, the plug cylinder (25a) is positioned below the upper end (25a) of the plug cylinder (25) and between the inlet (64a) position of the guide passage (64). The cam bearing oil supply structure for an internal combustion engine according to any one of claims 1 to 3, further comprising a raised portion (25g) that is annularly raised from an outer periphery of 25) .

According to a fifth aspect of the present invention, the upper end surface (25e) of the upper end portion (25a) of the plug cylinder (25) has an annular seal member (28) interposed so as to be in close contact with the upper end surface (25e). The cam bearing oil supply structure for an internal combustion engine according to any one of claims 1 to 4, characterized in that a holder portion (50) for retaining and fixing from the inside is provided.

According to a sixth aspect of the present invention, the cam bearing portion (38) is composed of upper and lower half bodies (38a, 38b) divided into upper and lower portions, and the holder portion (50) is formed of the upper half body (38a). When a cam bearing lubrication structure for an internal combustion engine according to claim 5, characterized in that integrally formed.

In the cam bearing oil supply structure for an internal combustion engine according to claim 1, the upper and lower ends of the plug cylinder are liquid-tightly fitted into the plug hole to form an outer peripheral oil passage, and the cam bearing portion is connected from the outer peripheral oil passage. Since the guide passage is formed as described above, the oil is directly supplied from the outer peripheral oil passage to the cam bearing portion via the guide passage, so that the oil passage to the cam bearing portion can be shortened. Thus, the cylinder head can be reduced in size, and the internal combustion engine can be reduced in size.
Since the outlet of the guide passage from the outer peripheral oil passage is provided on the semicircular surface on the plug hole side of the cam bearing portion, the length of the guide passage is shortened as much as possible and the time for supplying oil to the cam bearing portion after starting is reduced. It can be shortened.
Since the guide passage is formed so as to pass through the screw hole between the cam shaft and the plug hole and the guide passage is sealed with the fastening member, the guide passage is formed by bypassing the screw hole. The guide paths can be connected in the shortest time, and the manufacturing cost can be reduced.

In the cam bearing oil supply structure of the internal combustion engine according to claim 2, when the cam bearing is divided into upper and lower halves and the guide passage is formed from a cam bearing formed in two upper and lower parts, By machining the cam bearing portion obliquely, the machining procedure can be easily performed.

In the cam bearing oil supply structure for an internal combustion engine according to claim 3, oil can be supplied to the cam bearing portions on both sides across the plug hole from the outer peripheral oil passage of the common plug hole. The road can be simplified.

In the cam bearing oil supply structure for an internal combustion engine according to claim 4, the annular oil passage is introduced from below by providing an annular raised portion provided on the outer periphery of the plug cylinder at a position above the inlet of the guide passage. It is possible to facilitate the supply of oil into the guide passage by promoting the flow of the rising oil to the inlet of the guide passage.

In the cam bearing oil supply structure of the internal combustion engine according to claim 5, the upper end surface of the plug cylinder constituting a part of the outer peripheral oil passage is fixed by a holder portion from above via an annular seal member. Therefore, it is possible to reliably suppress the plug cylinder that is easily pulled out by receiving hydraulic pressure.

In the cam bearing oil supply structure for an internal combustion engine according to claim 6, the cam bearing portion is composed of upper and lower halves divided into upper and lower parts. When the holder portion is provided, the holder portion is By integrally forming the upper half, the number of parts can be reduced, and the manufacturing cost can be reduced.

1 is a left side view of an internal combustion engine having a cam bearing oil supply structure for an internal combustion engine according to an embodiment of the present invention. It is a longitudinal cross-sectional view of the internal combustion engine cut | disconnected by the plane which passes along the centerline of an intake valve, and the centerline of an exhaust valve. FIG. 3 is a secondary sectional view of the internal combustion engine cut along a plane passing through the center line of the combustion plug cylinder. It is a perspective view of the internal combustion engine which removed the head cover. It is the VV arrow line view of FIG. It is a principal part expanded sectional view of FIG. It is a VII-VII arrow line view of FIG. It is a principal part expanded sectional view of FIG. It is a principal part expanded sectional view of FIG.

  A cam bearing oil supply structure for an internal combustion engine according to an embodiment of the present invention shown in FIGS. 1 to 9 will be described below. In this embodiment, front and rear, up and down, and left and right directions mean front and rear, up and down, and left and right of a vehicle body (not shown) on which the internal combustion engine is mounted.

FIG. 1 is a side view of an internal combustion engine 1 having a cam bearing oil supply structure 60 according to an embodiment of the present invention as viewed from the left. In the internal combustion engine 1, a cylinder block 3, a cylinder head 4, and a head cover 5 are sequentially stacked on a crankcase 2, and are fastened together with a bolt (not shown), and an oil pan 6 is fastened with a bolt (not shown) on the lower surface of the crankcase 2. It is a thing. The internal combustion engine 1 is a four-cylinder in-line internal combustion engine in which four cylinders 11 are formed in the left-right direction in a cylinder block 3, and an intake valve 18 and an exhaust valve 19 are provided as shown in FIGS. A valve operating mechanism 30 of a DOHC type four-valve system that is driven to open and close is accommodated in a valve operating chamber 31 that includes a cylinder head 4 and a head cover 5.

As shown in FIG. 1, a crankshaft 10 is supported between the crankcase 2 and the cylinder block 3 so as to be rotatable in the left-right direction. As shown in FIG. 2, a piston 12 that slides up and down is fitted in a cylinder 11 formed in the cylinder block 3, and the piston 12 is connected to a crankshaft 10 via a connecting rod (not shown). It is connected to. The cylinder head 4, a combustion chamber 13 formed of the recess at a position facing the cylinder bore 11a of the cylinder 11 in the cylinder axis direction is formed by the explosion of fuel combusted in the combustion chamber 13, the piston 12 is The crankshaft 10 is driven to rotate by the vertical movement of the piston 12 that is slid up and down in the Linda 11 .

  In each combustion chamber 13, two intake ports 14 and two exhaust ports 15 are formed, and an intake port 16 for introducing intake air into the combustion chamber 13 and an exhaust port 17 for discharging exhaust gas generated in the combustion chamber 13. Is communicated. An intake valve 18 and an exhaust valve 19 that open and close the intake port 14 and the exhaust port 15 are slidably supported by a valve guide 20, and are attached to the upper retainer 21 fixed to the upper ends of the valve shafts 18 a and 19 a and the cylinder head 4. A spring 23 fitted between the fixed lower retainers 22 is always urged in the valve closing direction.

  As shown in FIGS. 3 and 5 to 7, a spark plug cylinder 25 is inserted and positioned substantially at the center of the intake port 14 and the exhaust port 15 in one cylinder of the cylinder head 4. A spark plug hole 24 to which a spark plug inserted into the cylinder 25 is attached is formed.

As shown in FIG. 6, the spark plug hole 24 is formed by connecting a plurality of circular holes having different concentric inner diameters, and is directed downward from the joint surface 59 between the upper surface of the cylinder head 4 and the camshaft holder 50. the main plug hole 24a Te is formed mainly continuous with the bottom of the plug hole 24a, an inner diameter of the plug tube fitting portion 24b of the lower end portion 25 b is fitted slightly smaller spark plug tube 25 is formed, the plug tube fitting portion A spark plug contact portion 24c having a smaller inner diameter is formed in communication with the lower portion of 24b, and a screw portion 24d is formed in communication with the lower portion of the spark plug contact portion 24c and screwed into the screw portion 26a of the spark plug 26. The tip of the screw portion 24d communicates with the combustion chamber 13.

  A spark plug cylinder 25 is inserted into the spark plug hole 24. The spark plug cylinder 25 has a cylindrical shape, and the outer diameter of the cylindrical intermediate portion 25c occupying most of the spark plug cylinder 25 is smaller than the inner diameter of the main plug hole 24a of the spark plug hole 24. The upper end portion 25a of the spark plug cylinder 25 is provided with a flange portion 25d having a diameter larger than the inner diameter of the main plug hole 24a of the spark plug hole 24. A lower end portion 25b of the spark plug cylinder 25 is fitted into a plug cylinder insertion portion 24b of the ignition plug hole 24, and a groove portion 25f into which the annular seal member 27 is fitted is formed in the lower end portion 25b. ing.

  The spark plug cylinder 25 is fixed and secured from above by a camshaft holder 50 described later. The camshaft holder 50 is formed with a contact portion 50a that contacts the flange portion of the spark plug cylinder 25, and a groove portion 50b into which the annular seal member 28 is fitted is formed in the corresponding contact portion 50a. ing. Further, the camshaft holder 50 is formed with a plug hole 50c that communicates with the inside of the spark plug cylinder 25 and into which the spark plug is inserted.

Spark plug tube 25 is inserted into the ignition plug bore 24 in a state in which the annular sealing member 27 is fitted into the groove 25 f of the lower portion 25b, the cam shaft holder 50 to annular sealing member 28 is fitted in the groove 50b When secured from above, the space formed by the inner peripheral surface of the spark plug hole 24 and the outer peripheral surface of the spark plug cylinder 25 (plug cylinder outer peripheral oil passage 63 to be described later) is formed by the annular seal members 27 and 28. The upper end portion 25a and the lower end portion 25b of the spark plug cylinder 25 are liquid-tight, and the interior of the cylinder head 4 and the spark plug hole 24 are partitioned by the spark plug cylinder 25.

After the inside of the spark plug cylinder 25 is secured to the cylinder head 4 by the camshaft holder 50, the spark plug 26 is inserted into the spark plug cylinder 25 from the plug hole 50c of the camshaft holder 50, and the tip of the spark plug 26 is inserted. The screw portion 26 a formed in the above is screwed into the screw portion 24 d of the spark plug hole 24, and the electrode portion 26 b of the spark plug 26 is attached so as to face the combustion chamber 13.

As shown in FIGS. 2 to 4, the intake camshaft 32 and the exhaust camshaft 33 are directed in the left-right direction of the internal combustion engine 1 so as to sandwich the spark plug hole 24 in the valve chamber 31. The cam is composed of a lower bearing portion 38b as a bearing half formed in the cylinder head 4 and an upper bearing portion 38a as a bearing half formed in the camshaft holder 50. The bearing portion 38 is rotatably supported.

  As shown in FIGS. 3 and 4, the cylinder head 4 is provided with two bolt screw holes 53, 54 on the front and rear sides of each spark plug hole 24. The bolt screw holes 54 are formed at positions sandwiching the lower bearing portion 38b. The camshaft holder 50 is provided with two bolt insertion holes 51 and 52 for the front and rear of the spark plug hole 24 corresponding to the bolt screw holes 53 and 54 formed in the cylinder head, The bolt insertion hole 51 and the bolt insertion hole 52 are respectively formed at positions sandwiching the upper bearing portion 38a.

  As shown in FIG. 8, cylindrical member insertion holes 51a and 53a having inner diameters slightly larger than the inner diameters are formed at the lower part of the bolt insertion hole 51 and the upper part of the bolt screw hole 53 on the intake camshaft 32 side. A cylindrical member 58 formed so as to insert the flange bolt 55 is fitted into the cylindrical member insertion holes 51a and 53a.

After the spark plug cylinder 25 is inserted into the spark plug hole 24 formed in the cylinder head 4 and the intake cam shaft 32 and the exhaust cam shaft 33 are placed at predetermined positions on the lower bearing portion 38 b formed in the cylinder head 4. Then, the camshaft holder 50 is placed so as to sandwich the intake camshaft 32 and the exhaust camshaft 33 , and the flange bolts 55 and 56 are inserted into the bolt insertion holes 51 and 52 of the annular seal member 57 and the camshaft holder 50, and the cylinder The camshaft holder 50 is fastened integrally with the cylinder head 4 by screwing into the bolt screw holes 53 and 54 of the head 4, and the intake camshaft 32 and the exhaust camshaft 33 are rotatably supported by the cam bearing portion 38. . Since the annular seal member 57 is interposed between the flange bolts 55 and 56 and the camshaft holder 50, the inside of the bolt insertion holes 51 and 52 and the inside of the bolt screw holes 53 and 54 are liquid-tight. .

  As shown in FIG. 4, a driven sprocket 41 is integrally attached to the right end portion of the intake camshaft 32, and the driven sprocket 41 and the drive sprocket 40 provided on the crankshaft 10 include An endless timing chain 42 is stretched over, and the intake camshaft 32 is rotated by the rotational driving force of the crankshaft 10.

An intake cam gear 36 is attached to substantially the center in the right direction of the intake cam shaft 32 so as to rotate integrally with the intake cam shaft 32, and an exhaust cam gear 37 is attached to the exhaust cam shaft 33 so as to mesh with the intake cam gear 36. It is attached integrally. The intake cam gear 36 and the exhaust cam gear 37, and the same number of teeth are formed, the rotational driving force of the intake cam shaft 32 which is rotated by the crankshaft 10, via the intake cam gear 36 and the exhaust cam gear 37 exhaust is transmitted to the camshaft 33, the exhaust camshaft 33 is rotated in the reverse direction by the intake cam shaft 3 2 the same rotational speed.

As shown in FIG. 2, an intake rocker arm 43 and an exhaust rocker arm 44 are supported on the cylinder head 4 by a rocker arm shaft 45 parallel to the intake / exhaust cam shafts 32 and 33 so as to be freely slidable. Arm portion 43a of the intake and exhaust rocker arms 43 and 44, the leading end upper surface of 44a cam contact portion 43 b, 44b is brought into contact with the cam surface 34 a, 35 a of the intake and exhaust cams 34, 35, arms 43a, 44a The valve shaft side abutting portions 43c and 44c on the lower surface of the tip end press the valve shafts 18a and 19a of the intake / exhaust valves 18 and 19 through the clearance adjusting member 29.

When the internal combustion engine 1 starts to start and the intake / exhaust cam shafts 32, 33 are rotated by the rotational driving force transmitted from the crankshaft 10, the intake / exhaust cams 34 , 35 are rotated, and the intake / exhaust cam 34 is rotated. 35, the cam contact portions 43b, 44b of the intake / exhaust rocker arms 43 , 44 are pressed in accordance with the shape of the cam surfaces 34a, 35a, and the intake / exhaust rocker arms 43 , 44 are swung to contact the valve shaft side contact portions. 43c and 44c press the valve shafts 18a and 19a of the intake / exhaust valves 18 and 19 through the clearance adjusting member 29, and the intake valve 18 and the exhaust valve 19 are opened and closed at a predetermined timing and lift amount.

Next, the cam bearing oil supply structure 60 that supplies lubricating oil to the cam bearing portion 38 will be described. As shown in FIG. 1, an oil pump 7 driven by the power of the crankshaft 10 is provided in the crankcase 2, and the oil pump 7 includes a strainer 8 disposed in the oil pan 6. When the oil pump 7 is driven by the crankshaft 10, the lubricating oil stored in the oil pan 6 is sucked from the strainer 8 and is supplied from the oil pump 7 through the supply oil passage 9 to the internal combustion engine. 1 is sent to various places.

Lubricating oil pumped from the oil pump 7 passes through a supply oil passage 9 a extending upward to the joint surface of the crankcase 2 and the cylinder block 3 toward the crankshaft 10, and joins the crankcase 2 and the cylinder block 3. A supply oil passage 9c formed in the cylinder head 4 from the cylinder block 3 passes obliquely upward from a front end portion of the supply oil passage 9b through a supply oil passage 9b formed forward of the cylinder block 3 along the surface. As shown in FIG. 5, the cylinder head 4 is sent to a main lubricating oil passage 62 formed in the left-right direction. The right end 62a of the main lubricant passage 62 is connected to the supply oil passage 9c, and the left end 62b of the main lubricant passage 62 is closed by a plug 70. As shown in FIGS. 3 and 5, the main lubricating oil passage 62 is formed so as to penetrate through the four spark plug holes 24 formed in the cylinder head 4.

As shown in FIGS. 6 and 7, the space constituted by the spark plug hole 24 the spark plug tube 25 is inserted, the inner peripheral surface of the spark plug hole 24 and the outer peripheral surface of the spark plug tube 25 The plug cylinder outer peripheral oil passage 63 is made fluid-tight at the upper end 25a and the lower end 25b of the spark plug cylinder 25 by the annular seal members 27, 28, and the inside of the cylinder head 4 and the spark plug hole 24 are connected to the spark plug Partitioned by a cylinder 25. As shown in FIG. 7, since the spark plug hole 24 communicates with the main lubricating oil passage 62, the lubricating oil flowing through the upstream main lubricating oil passage 62 flows from the inlet 63a of the plug cylinder outer peripheral oil passage 63. It flows into the plug cylinder outer peripheral oil path 63, bypasses along the outer peripheral surface of the spark plug cylinder 25, and flows out into the main lubricating oil path 62 downstream from the outlet 63b of the plug cylinder outer peripheral oil path 63. Yes.

As shown in FIGS. 3, 8 and 9, the joint surface between the camshaft holder 50 and the cylinder head 4 passes through the lower bearing portion 38 b formed in the cylinder head 4 from the plug cylinder outer peripheral oil passage 63. Guide passages 64 are formed so as to be inclined with respect to 59 and directed to the spark plug hole 24 and connected to the sliding surfaces of the intake camshaft 32 and the cam bearing portion 38, and the exhaust camshaft 33 and the cam bearing portion 38, respectively. ing. The inlet 64a of the guide passage 64 communicates with the plug cylinder outer peripheral oil passage 63, and the outlet 64b to the cam bearing portion 38 is on the ignition plug hole 24 side with respect to the rotation center of the intake and exhaust camshafts 32 and 33. Is provided on the plug-side semicircular surface 38c.

  As shown in FIG. 6, the spark plug cylinder 25 is positioned above the inlet 64 a of the guide passage 64 communicating with the plug cylinder outer peripheral oil path 63 and below the upper end portion 25 a of the spark plug cylinder 25. Thus, a raised portion 25g that is raised in an annular shape from the outer peripheral surface of the intermediate portion 25c is formed. The raised portion 25g promotes the flow of the lubricating oil that has flowed into the plug cylinder outer peripheral oil passage 25 from below into the inlet 64a of the guide passage 64.

As shown in FIGS. 8 and 9, the guide passage 64 is formed so as to penetrate a bolt screw hole 53 provided between the spark plug hole 24 and the intake cam shaft 32 or the exhaust cam shaft 32. The flange bolts 55 and 56 and the annular seal member 57 screwed into the bolt screw hole 53 are sealed so that the lubricating oil does not leak from the guide passage 64.

In the cam bearing oil supply structure 60 of this embodiment, the lubricating oil sent from the oil pump 7 passes through the supply oil passage 9 as shown in FIG. 1, and as shown in FIG. 9 is sent to the right end 62a of the main lubricating oil passage 62, and is sequentially sent from the right end 62a to the plug cylinder outer peripheral oil passage 63 provided in each cylinder. Furthermore, as shown in FIGS. 8 and 9, flows from the plug cylinder-peripheral oil passage 63 into the guide passage 64 through the bolt insertion holes 5 1, formed in the plug-side half circumferential surface 38c of the cam bearing portions 38 From the outflow port 64b, the lubricating oil is supplied to the sliding surface between the cam bearing portion 38 and the intake / exhaust cam shafts 32, 33. As shown in FIG. 8, the joint surface between the upper bearing portion 38a and the lower bearing portion 38b on the intake cam shaft 32 side, that is, the joint surface 59 between the cylinder head 4 and the camshaft holder 50 is directed to the spark plug hole 24 side. The lubricating oil that is inclined and flows into the outflow port 64b cam bearing portion 38 is directed downward through the joint surface 59, but is inserted into the bolt by the cylindrical member 58 fitted in the bolt insertion hole 51 and the bolt screw hole 53. It is possible to prevent the lubricating oil from flowing into the hole 51 and the bolt screw hole 53, and to send sufficient lubricating oil to the cam bearing portion .

Since the cam bearing oil supply structure 60 of the internal combustion engine 1 according to the embodiment of the present invention is configured as described above, the upper and lower ends 25a and 25b of the spark plug cylinder 25 are fitted into the spark plug hole 24 in a liquid-tight manner. The plug cylinder outer peripheral oil path 63 is formed, and the guide passage 64 is formed so as to connect the cam bearing portion 38 from the plug cylinder outer peripheral oil path 63, so that the cam is connected from the plug cylinder outer peripheral oil path 63 via the guide passage 64. Since the lubricating oil is directly supplied to the bearing portion 38, the lubricating oil passage to the cam bearing portion 38 can be shortened, and consequently the cylinder head 4 can be made smaller to reduce the size of the internal combustion engine 1. Can do.

Furthermore, since there is provided a plug tube outer peripheral oil passage 63 to the outlet 63 b of the guide passage 64 to the spark plug hole 24 side of the plug-side half circumferential surface 38c of the cam bearing portions 38, the length of the guide passage 64 as short as possible In addition, the time for supplying oil to the cam bearing portion 38 after the internal combustion engine 1 is started can be shortened.

Further, a guide passage 64 is formed so as to pass through the bolt screw hole 53 between the intake / exhaust cam shafts 32, 33 and the spark plug hole 24, and the guide passage 64 is sealed with the flange bolt 55. Therefore, as compared with the case where the guide passage 64 is formed by bypassing the bolt screw hole 53, the guide passage 64 can be connected in the shortest time, and space can be saved and the processing cost can be reduced.

Further, the cam bearing portion 38 is divided into upper and lower halves of the upper bearing portion 38a and the lower bearing portion 38b, and the guide passage 64 is inclined with respect to the joint surface of the upper bearing portion 38a and the lower bearing portion 38b with respect to 59, and ignition is performed. because it is processed and formed to face the plug hole 24, the guide passage 64 vertically bisected on formed and lower bearings unit 38a, when 38b to the processing form, the upper and lower shaft receiving portion 38a, 38b The processing procedure can be easily performed by putting processing into the slant.

Further, the cylinder head 4 is provided with a plurality of cam shafts 32 and 33 sandwiching the spark plug hole 24, and a pair of guide passages 64 are formed in each cam bearing portion 38. Thus, it is possible to supply the lubricating oil to the cam bearing portions 38 on both sides from the plug cylinder outer peripheral oil passage 63 of the common spark plug hole 24, and the oil supply can be simplified.

  Since a raised portion 25g that protrudes annularly from the outer periphery of the spark plug cylinder 25 is provided between the position of the inlet 64a of the guide passage 64 and a position below the upper end 25a of the spark plug cylinder 25, the plug cylinder It is possible to facilitate the supply of the lubricating oil into the guide passage 64 by accelerating the flow of the lubricating oil flowing in the outer peripheral oil passage 63 from below to the inlet 64a of the guide passage 64.

Since the camshaft holder 50 is attached so that the upper end surface 25e of the spark plug cylinder 25 constituting a part of the plug cylinder outer peripheral oil passage 63 is pressed through the annular seal member 28, the camshaft holder 50 is easily pulled out by receiving hydraulic pressure. The spark plug cylinder 25 can be reliably suppressed.

  The cam bearing part is composed of upper and lower half parts that are divided into upper and lower parts, and the holder part is integrally formed with the upper half body. When the holder part is provided, the cam bearing part is integrally formed with the upper half body of the cam bearing part. Therefore, the number of parts can be reduced.

DESCRIPTION OF SYMBOLS 1 ... Internal combustion engine, 4 ... Cylinder head, 13 ... Combustion chamber, 24 ... Spark plug hole, 25 ... Spark plug cylinder, 25e ... Upper end surface , 25g ... Raised part, 26 ... Spark plug, 28 ... Annular seal member, 32 ... intake camshaft, 33 ... exhaust camshaft, 38 ... cam bearing portions, 38a ... upper bearing portion, 38b ... lower bearing portion, 50 ... cam shaft holder, 55 ... flange bolts, 53 ... bolt screw holes, 6 2 ... main lubrication Oil passage, 63 ... plug cylinder outer periphery oil passage, 64 ... guide passage, 64a ... inflow port, 64b ... outflow port.

Claims (6)

A cylinder head (4) having a cam bearing portion (38) for rotatably supporting the cam shaft (3 2 , 3 3 );
A plug hole (24) for accommodating a spark plug (26) supported by the cylinder head (4) with the tip facing the combustion chamber (13);
A cylindrical shape is inserted into the plug hole (24) in a liquid-tight manner at the upper and lower end portions (25a, 25b), so that the inside of the cylinder head (4) and the plug hole (24) In a cam bearing oil supply structure of an internal combustion engine provided with a plug cylinder (25) that partitions
Wherein the upper and lower portion of the plug hole (24) and the plug tube (25) (25a, 25b) in the liquid-tight, the outer peripheral oil passage which bypasses along the outer peripheral surface of the plug tube (25) (63 )When,
A main lubricating oil passage (62) formed so as to pass through the plug hole (24) in the cylinder head (4) and to be connected by the outer peripheral oil passage (63);
The cam bearing portion (38) is formed so as to connect the sliding surface of the cam bearing portion (38) from the outer peripheral oil passage (63), and the cam bearing portion (38) and the cam shaft ( 3 2, 3 3) and provided with guide channel (64) for supplying lubricating oil reaches the sliding surface of,
A semicircular surface on the side of the plug hole (24) with respect to the rotation center of the cam shaft (32 , 33) , the outlet (64b) of the guide passage (64) to the cam bearing portion (38). (38c)
The cam bearing portion (38) is composed of a plurality of divided halves (38a, 38b), and is used for a fastening member (55) for connecting them, the cam shaft (32, 33) and the plug A screw hole (53) provided between the hole (24) and the guide passage (64) is formed through the screw hole (53), and the screw hole (53) is sealed by the fastening member (55). A cam bearing oil supply structure for an internal combustion engine. The cam bearing portion (38) is divided into upper and lower half bodies (38a, 38b), and the guide passage (64) is inclined with respect to the joint surface (59) of the upper and lower half bodies (38a, 38b). The cam bearing oil supply structure for an internal combustion engine according to claim 1, wherein the cam bearing oil supply structure is formed so as to be directed toward the plug hole (24) . The cylinder head (4) is provided with a plurality of cam shafts (32, 33) sandwiching the plug hole (24), and a pair of guide passages (64) are formed in each cam bearing portion (38). 3. A cam bearing oil supply structure for an internal combustion engine according to claim 1 or 2. It protrudes annularly from the outer periphery of the plug cylinder (25) between the upper end (25a) of the plug cylinder (25) and the inlet (64a) position of the guide passage (64). The cam bearing oil supply structure for an internal combustion engine according to any one of claims 1 to 3, further comprising a raised portion (25g) . The upper end surface (25e) of the upper end portion (25a) of the plug cylinder (25) is interposed with an annular seal member (28) in close contact with the holder portion (50 cam bearing lubrication structure for an internal combustion engine according to any one of claims 1 to 4), characterized in that it has disposed. The cam bearing part (38) is composed of upper and lower half bodies (38a, 38b) divided into upper and lower parts, and the holder part (50) is constructed integrally with the upper half body (38a). The cam bearing oil supply structure for an internal combustion engine according to claim 5 .

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