JP2013083197A - Cam phase variable type internal combustion engine - Google Patents

Abstract

PROBLEM TO BE SOLVED: To control an increase in weight of an internal combustion engine by making compact a circumference of an oil path section toward a cam phase varying device.SOLUTION: An engine 1 is provided with an advancing angle annular groove 49 and a retarding angle annular groove 46 formed on a bearing surface of a first journal bearing wall 15. A spool valve 35 is placed along the first journal bearing wall. A retarding angle oil path 44 is equipped with a first oil path 47 which is formed on a joint surface 20 between a cam cap 18 and a cam holder 16 and is connected to the retarding angle annular groove 46, and a second oil path 48 which is formed on the cam holder 16 and connects the spool valve 35 and the first oil path 47. An advancing angle oil path 43 is equipped with a third oil path 50 which is formed on the cam holder 16 and is connected to the spool valve 35 and the advancing angle annular groove 49. The second oil path 48 and the third oil path 50 are placed on a same plane perpendicular in a camshaft direction.

Description

  The present invention relates to a cam phase variable internal combustion engine including a hydraulic cam phase varying device that changes valve timing, and relates to an oil passage structure for improving the response of the cam phase varying device.

  In an internal combustion engine mounted on an automobile or the like, a cam phase variable device (variable valve timing device) that variably controls the rotation phase of the camshaft with respect to the crankshaft in order to change the opening / closing timing of the intake valve and exhaust valve according to the operating state. : VTC). The cam phase varying device includes a housing that is rotationally driven by a crankshaft, and an advance oil chamber and a retard oil that are fixed to one end of the camshaft and are rotatably accommodated in the housing. 2. Description of the Related Art It is known to have a rotor that defines a chamber and to switch the supply of hydraulic oil to an advance oil chamber and a retard oil chamber by a hydraulic control valve provided in the oil passage (for example, Patent Document 1). reference).

  In such a cam phase variable internal combustion engine, two oil passages of an advance oil passage and a retard oil passage are formed between the hydraulic control valve and the cam phase variable device, and these oil passages are There may be a case where a journal bearing wall supporting the crankshaft is provided so as to reach the advance oil chamber and the retard oil chamber via the camshaft.

  On the other hand, the journal bearing wall is formed of a cam holder having a half bearing surface and a cam cap having a half bearing surface formed on the cylinder head, and the cam cap sandwiches the cam shaft so as to sandwich the cam shaft. Fastened to the cam holder by bolts arranged in the vicinity. Accordingly, in the case of the oil passage arrangement as described above, it is difficult to form two systems of oil passages by avoiding bolts without increasing the size of the journal bearing wall.

  Against this backdrop, the oil passage structure formed on the journal bearing wall is used as a camshaft rather than a bolt as an oil passage structure for realizing a compact oil passage and avoiding an increase in the size of the bolt for fastening the cam cap. An invention has been proposed in which two first oil grooves are formed on the cam holder joint surface of the cam cap so as to avoid bolts and connect to the bearing surface of the journal bearing wall. Reference 2).

JP 2010-190159 A Japanese Patent No. 3355356

  However, in the invention of Patent Document 2, it is possible to avoid an increase in the size of the bolt for fastening the cam cap, but since the two first oil grooves are formed on the side of the bolt, the cam cap is connected to the fastening boss portion. The cam cap is also wide in the periphery, and the cam cap cannot be sufficiently reduced in size. Here, it is conceivable that only the oil passage forming portion is widened around the fastening boss portion of the cam cap, but in this case, a high pressure oil passage is formed on the cam holder joint surface. Oil leakage is likely to occur.

  Further, in the invention of Patent Document 1, two oil passages that respectively connect the oil control valve provided in the cylinder head and the two first oil grooves are provided in the camshaft direction from the oil control valve (refer to Patent Document 2). 2 (in FIG. 2), the engine (cylinder head) is enlarged in the camshaft direction, and it is difficult to reduce the thickness of this portion.

  The present invention has been devised in order to solve the problems included in the prior art, and is intended to suppress the increase in the weight of the internal combustion engine by downsizing the periphery of the oil passage to the cam phase varying device. In addition, the second object is to prevent oil leakage from the joint surface between the cam cap and the cam holder.

  In order to solve such a problem, according to one aspect of the present invention, rotation is performed by a journal bearing wall (15) including a cam holder (16) and a cam cap (18) fastened to the cam holder by a bolt (19). The camshaft (10) is supported freely, and the cam phase is provided by supplying hydraulic oil to the advance hydraulic chamber (33) and the retard hydraulic chamber (34) provided at the end of the camshaft. The cam phase varying device (30) for changing the pressure, and the oil passage (40) communicating with the hydraulic pressure supply source (21) and the cam phase varying device are provided, and the advance hydraulic chamber and the retard hydraulic chamber are provided. A hydraulic control valve (35) for controlling the supply of the hydraulic oil to the hydraulic oil passage, and the oil passage includes an upstream oil passage (41) communicating the hydraulic supply source and the hydraulic control valve, and the hydraulic control. For valve and advance angle A cam phase variable internal combustion engine (1) having an advance oil passage (43) communicating with a pressure chamber and a retard oil passage (44) communicating between the hydraulic control valve and the retard hydraulic chamber. The advance oil passage is formed in an annular shape on the bearing surface of the journal bearing wall so as to supply the hydraulic oil to the advance hydraulic chamber via the camshaft. The retarding oil passage has an annular groove (49), and is offset in the camshaft direction with respect to the advancement annular groove so as to supply the hydraulic oil to the retarding hydraulic chamber via the camshaft. And the retard angle annular groove (46) formed in an annular shape on the bearing surface of the journal bearing wall at the position, and the hydraulic control valve is formed with the advance angle groove groove and the angle delay groove portion. Arranged along the axis of the journal bearing wall, the advance oil passage and the A first oil in which one of the corner oil passages is formed on the joint surface (20) between the cam cap and the cam holder and one end (47a) is connected to the advance angle annular groove portion or the retard angle annular groove portion. A passage portion (47); and a second oil passage portion (48) formed in the cam holder and connecting the hydraulic control valve and the other end (47b) of the first oil passage portion, and the advance angle The other of the oil passage and the retarding oil passage is a third oil passage portion (50) formed in the cam holder and connected to the hydraulic control valve and the advancement annular groove portion or the retarding annular groove portion. ), And the second oil passage portion and the third oil passage portion are arranged on the same plane perpendicular to the cam shaft direction.

  According to this configuration, since the second oil passage portion and the third oil passage portion are disposed on the same plane orthogonal to the cam shaft direction, the second oil passage portion and the third oil passage portion are defined. The thickness of the portion can be reduced, and the internal combustion engine can be prevented from being enlarged in the camshaft direction. Further, since only the first oil passage portion is formed on the joint surface between the cam cap and the cam holder, the width of the joint surface can be narrowed to reduce the size of the cam cap. Furthermore, since the hydraulic control valve is disposed along the journal bearing wall, it is possible to avoid an increase in the thickness of the mounting portion of the hydraulic control valve.

  According to another aspect of the present invention, the cam cap (18) has a pair of bolt insertion holes (52) through which the bolts (19) are inserted at positions sandwiching the cam shaft (10). The bolt insertion hole (52o) on one side where the first oil passage portion is formed on the joint surface with the cam holder is the center of the advance angle annular groove portion and the retard angle annular groove portion in the cam shaft direction. (15X) is disposed at a position offset to the side opposite to the advance annular groove portion or retard angle annular groove portion (46) to which the first oil passage portion is connected, and the first oil passage The said other end (47b) of a part can be set as the structure located in the opposite side to the said cam shaft with respect to the said one bolt insertion hole (52o) about the direction orthogonal to a cam shaft direction.

  Since the cam phase variable device is operated only by the hydraulic pressure from the hydraulic control valve, if the hydraulic pressure is insufficient due to oil leakage in the middle of the oil passage, the responsiveness deteriorates. Since the bolt insertion hole can be arranged in the vicinity of the camshaft on the one side where the first oil passage is formed, the mounting rigidity of the cam cap can be increased, and oil leakage from the joint surface on which the first oil passage portion is formed can be prevented. In addition, since the first oil passage portion can be disposed in a region vacated by the offset of the bolt insertion hole on one side in the cam shaft direction, the joint surface becomes larger in the cam shaft direction to form the first oil passage portion. Can be suppressed.

  According to another aspect of the present invention, the cam holder (16) has a pair of bolt holes (25) for screwing the bolts at positions corresponding to the pair of bolt insertion holes, and A holder-side protruding portion (26) protruding to the side opposite to the first oil passage portion with respect to the wall portion defining the side bolt hole (25o), and the cam cap (18) A cap-side protrusion (57) that protrudes to the side opposite to the first oil passage part with respect to the fastening boss part (53o) that defines the bolt insertion hole (52o) on the side and is joined to the holder-side protrusion part ).

  Since the bolt insertion hole on one side is offset in the cam shaft direction and the first oil passage portion is disposed on the opposite side to the offset side, the cam cap is opposite to the first oil passage portion due to the hydraulic pressure of the first oil passage portion. However, according to this configuration, the inclination of the cam cap can be prevented by joining the holder-side protruding portion and the cap-side protruding portion, and oil leakage from the gap between the cam cap and the cam holder can be suppressed.

  According to another aspect of the present invention, the cam cap (18) includes a pair of fastening boss portions (53) fastened by the bolt at a position sandwiching the camshaft (10), and the cam holder. A projecting plate portion (54) that protrudes along the joining surface (20) from a fastening boss portion (53o) on one side where the first oil passage portion is formed on the joining surface and defines the first oil passage portion. And a rib (55) that protrudes from a surface opposite to the joint surface of the protruding plate portion and is connected to the fastening boss portion on the one side.

  According to this structure, it is not necessary to make the periphery of the fastening boss part unnecessarily wide (thick) by projecting the protruding wall part from the fastening boss part to the part defining the first oil passage part. The cam cap can be reduced in size and weight. In addition, by providing ribs that are connected to the fastening bosses on the projecting wall, even if high pressure oil pressure is applied to the first oil passage, the joint surface between the cam cap and the cam holder opens and oil leakage occurs. Can be prevented.

  Further, according to one aspect of the present invention, the rib may be formed to project at a portion corresponding to the other end (47b) of the first oil passage portion in the projecting plate portion.

  The other end of the first oil passage portion has the highest possibility of oil leakage because the second oil passage portion is connected from the cam holder side. According to this configuration, the first oil passage has the highest possibility of oil leakage. Since the rib is provided at the site that defines the other end of the part, oil leakage can be reliably prevented.

  According to another aspect of the present invention, the cam phase varying device (30) is provided in the camshaft (10) on the exhaust side, and the retarding oil passage (44) is provided in the first oil passage portion ( 47).

  According to this configuration, the advance oil passage passes through the third oil passage portion formed in the cam holder to reach the advance annular groove portion and does not pass through the first oil passage portion formed in the joint surface. Oil leakage does not occur from the joint surface. Therefore, the camshaft can be quickly and surely returned in the advance direction while the internal combustion engine is stopped or at the time of starting the engine, and the ignitability and startability at the next engine start can be ensured.

  As described above, according to the present invention, oil leakage from the joint surface between the cam cap and the cam holder can be prevented while the oil passage portion around the cam phase varying device is made compact to suppress an increase in the weight of the internal combustion engine. Can do.

The principal part perspective view of the engine which concerns on embodiment Side view of engine block and cylinder block shown in FIG. Plan view of the cylinder block shown in FIG. Schematic configuration diagram of the spool valve shown in FIG. The perspective view of the principal part of the cylinder block shown in FIG. FIG. 1 is a plan view of the main part of the cylinder block shown in FIG. Bottom view of the cam cap shown in FIG. 3 is a perspective view of the main part of the cylinder block shown in FIG. 3 is a perspective view of the cam cap shown in FIG. Schematic configuration diagram of the VTC actuator shown in FIG.

  Hereinafter, an embodiment in which a cam phase varying device according to the present invention is applied to an automobile engine will be described in detail with reference to the drawings.

  As shown in FIG. 1, an engine (cam phase variable internal combustion engine) 1 is a DOHC 4-valve type 4-cycle in-line three-cylinder gasoline engine. A cylinder block 2 of the engine 1 includes three cylinders, and a piston 3 is slidably accommodated in each cylinder. The piston 3 is connected via a connecting rod 4 to a crankshaft 5 that is rotatably supported by the cylinder block 2. The cylinder head 6 provided at the upper part of the cylinder block 2 includes two intake valves 7 and exhaust valves 8 for each cylinder, and intake camshaft 9 and exhaust camshaft 10 that drive the intake and exhaust valves 7 and 8. Is provided.

  A crank sprocket 11 that rotates integrally with the crankshaft 5 is provided at one end of the crankshaft 5, and an intake cam sprocket 12 is provided at one end corresponding to the crank sprocket 11 of the intake camshaft 9. Further, a VTC actuator (cam phase varying device) 30 having an exhaust cam sprocket 13 is provided at one end corresponding to the crank sprocket 11 of the exhaust camshaft 10. The crank sprocket 11, the intake cam sprocket 12, and the exhaust cam sprocket 13 are spanned by a cam chain 14 that transmits rotation to each other. The camshafts 9, 10 have a rotational speed of ½ by the crankshaft 5. Driven by rotation.

  As shown in FIGS. 2 and 3, the intake camshaft 9 and the exhaust camshaft 10 are divided into a cam holder 16 having a half bearing surface integrally formed with the cylinder head 6, and a half split similarly fastened to the cam holder 16. Are supported rotatably by a journal bearing wall 15 comprising intake side and exhaust side cam caps 17 and 18 each having a bearing surface. The journal bearing walls 15 are provided at a total of four locations, that is, three locations that pass through the center of each cylinder in the cylinder row direction and one location in the vicinity of the intake cam sprocket 12 and the exhaust cam sprocket 13. Each of the cam caps 17 and 18 is fastened to the cam holder 16 by two bolts 19 arranged at a position sandwiching the intake camshaft 9 or the exhaust camshaft 10. Hereinafter, the journal bearing wall 15 forming the end surfaces of the cylinder head 6 on both cam sprockets 12 and 13 side is referred to as a “first journal bearing wall 15”, and the cam holder 16 (end surface of the cylinder head 6) constituting the first journal bearing wall 15. And the exhaust-side cam cap 18 will be referred to as “first cam holder 16” and “first exhaust cam cap 18”, respectively.

  Returning to FIG. 1, an oil pump 21 is provided in the lower part of the engine 1, and an oil pump chain 22 is stretched between a drive shaft of the oil pump 21 and a sprocket (not shown) provided on the crankshaft 5. An oil passage 40 for supplying engine oil pumped from the oil pump 21 to the VTC actuator 30 is formed in the cylinder block 2 and the cylinder head 6. The oil pump 21 is driven by the rotation of the crankshaft 5 and pumps the engine oil stored in the oil pan 23 to the VTC actuator 30 via the oil passage 40 and also to each part of the engine 1.

  As shown in FIG. 10, the VTC actuator 30 includes a housing 31 formed integrally with the exhaust cam sprocket 13 and a rotor 32 housed in the housing 31 and formed integrally with the exhaust camshaft 10 as main components. I have. An advance hydraulic chamber 33 and a retard hydraulic chamber 34 are defined between the rotor 32 and the housing 31, and the oil pump 21 is provided in one of the advance hydraulic chamber 33 and the retard hydraulic chamber 34. As a result, the rotor 32 and the housing 31 rotate relative to each other to change the cam phase of the exhaust camshaft 10.

  Supply of engine oil to the advance hydraulic chamber 33 and the retard hydraulic chamber 34 is controlled by a spool valve 35 provided in an oil passage 40 that connects the oil pump 21 and the VTC actuator 30. The spool valve 35 is attached to a valve attachment hole 24 (see FIG. 1) formed in the first journal bearing wall 15 in the vicinity of the VTC actuator 30. The valve mounting hole 24 has a cylindrical shape and an axis thereof is formed along the first journal bearing wall 15. That is, the spool valve 35 is also provided with its axis line along the first journal bearing wall 15. The valve mounting hole 24 to which the spool valve 35 is mounted has one upstream oil passage 41 connected to the oil pump 21, an advance oil passage 43 connected to the advance hydraulic chamber 33, and a retard hydraulic chamber. A downstream oil passage 42 including a retarding oil passage 44 connected to 34 and a drain oil passage 45 for returning the engine oil discharged from the VTC actuator 30 to the oil pan 23 are connected.

  As shown in FIG. 4, the spool valve 35 includes a valve sleeve 36 that is press-fitted into the valve mounting hole 24, a spool 37 that is slidably fitted in the valve sleeve 36, and an axis line of the spool 37 with respect to the valve sleeve 36. And a linear solenoid 38 driven in the direction. When the phase of the exhaust camshaft 10 is changed to the retard side, the spool valve 35 is driven upstream by driving the spool 37 to the near side (linear solenoid 38 side) by the linear solenoid 38 as shown in FIG. The side oil passage 41 is communicated with the retarding oil passage 44 and the advance oil passage 43 is communicated with the drain oil passage 45. When the phase of the exhaust camshaft 10 is changed to the advance side, the spool valve 35 drives the spool 37 to the back side by the linear solenoid 38 as shown in FIG. Is communicated with the advance oil passage 43 and the retard oil passage 44 is communicated with the drain oil passage 45. Further, when the phase of the exhaust camshaft 10 is held at the intermediate position, the spool valve 35 holds the spool 37 at the intermediate position by the linear solenoid 38 as shown in FIG. All of the advance oil passage 43 and the retard oil passage 44 are blocked.

  As shown in FIGS. 5 and 6, the retarding oil passage 44 is annular on the bearing surface of the first journal bearing wall 15 so as to supply engine oil to the retarding hydraulic chamber 34 via the exhaust camshaft 10. And a first oil passage portion formed on the joining surface 20 of the first exhaust cam cap 18 and the first cam holder 16 and having one end 47a connected to the retarding annular groove portion 46. 47 and a linear second oil passage portion 48 that is formed in the first cam holder 16 and connects the valve mounting hole 24 and the other end 47 b of the first oil passage portion 47. The second oil passage portion 48 is disposed on a plane orthogonal to the cam shaft direction. More specifically, the second oil passage portion 48 extends in parallel with the cylinder axial direction, and is disposed orthogonal to the joint surface 20 between the first cam holder 16 and the first exhaust cam cap 18.

  The first oil passage portion 47 is formed on the side opposite to the intake camshaft, that is, on the exhaust surface side of the cylinder head 6 in which the valve mounting hole 24 is formed, of the pair of joint surfaces 20 sandwiching the exhaust camshaft 10. Has been. Hereinafter, the side on which the first oil passage portion 47 is formed on the joint surface 20 will be referred to as the outside, and the opposite side will be referred to as the inside, and “o” or “i” will be added after the reference numerals, respectively.

  On the other hand, the advance oil passage 43 is connected to the retarded annular groove 46 and the cam shaft direction (the side opposite to the VTC actuator 30) to supply engine oil to the advance hydraulic chamber 33 via the exhaust camshaft 10. An advance angle annular groove 49 annularly formed on the bearing surface of the first journal bearing wall 15 at a position offset to the first cam holder 16, and a valve mounting hole 24 and an advance angle annular groove 49 formed in the first cam holder 16. And a linear third oil passage portion 50 connected thereto. The third oil passage portion 50 is disposed so as to be inclined with respect to the cylinder axis direction on the same plane orthogonal to the second oil passage portion 48 and the cam shaft direction.

  The retarding annular groove 46 and the advance annular groove 49 are formed so as to be symmetrical (surface object) with respect to the center line 15X in the cam shaft direction on the bearing surface of the first journal bearing wall 15. Here, the second oil passage 48, the third oil passage 50 and the upstream oil passage 41 are formed by drilling the cylinder head 6 and the wall of the cylinder block 2. In addition, it is also possible to form the 2nd oil path part 48, the 3rd oil path part 50, and the upstream oil path 41 using a core.

  The first cam holder 16 has a pair of bolt holes 25 into which a pair of bolts 19 for fastening the first exhaust cam cap 18 are screwed.

  As shown in FIGS. 7 to 9, the first exhaust cam cap 18 is a pair of bolts 19 inserted through the arc plate-shaped cap portion 51 defining the journal bearing surface and the exhaust camshaft 10. The bolt insertion hole 52 and a pair of fastening boss portions 53 that define the bolt insertion hole 52 are provided. The inner bolt insertion hole 52i is arranged in the center of the cap portion 51, more specifically, between the advance angle annular groove portion 49 and the retard angle annular groove portion 46 in the cam shaft direction. On the other hand, the outer bolt insertion hole 52o is offset from the center line 15X of the bearing surface defined by the cap portion 51 in the cam shaft direction toward the advance annular groove portion 49, more specifically, the advance annular groove portion 49. On the other hand, it is arranged on the opposite side to the retarding annular groove 46. In addition, the specification of the position here is based on the center of the bolt insertion hole 52 based on the technical significance of downsizing the oil passage arrangement.

  The first oil passage portion 47 is inclined with respect to a surface orthogonal to the cam shaft direction (passing from one end 47a to the other end 47b) so as to pass through a position separated from the outer bolt insertion hole 52o by a predetermined distance or more. The other end 47b is located outside the outer bolt insertion hole 52o, that is, the exhaust camshaft with respect to the outer bolt insertion hole 52o in the direction orthogonal to the cam shaft direction. 10 is located on the opposite side.

  Further, the first exhaust cam cap 18 protrudes along the joint surface 20 with a height dimension smaller than that of the outer fastening boss portion 53o from the outer fastening boss portion 53o so as to define the first oil passage portion 47. A protruding plate portion 54 is formed. A rib 55 is formed so as to protrude from the surface opposite to the joint surface 20 of the protruding plate portion 54. The rib 55 is disposed at a portion corresponding to the other end 47b of the first oil passage portion 47 in the protruding plate portion 54 and is connected to the outer fastening boss portion 53o. It has a shape.

  Further, the first exhaust cam cap 18 is formed with a cap-side protruding portion 57 that protrudes to the side opposite to the first oil passage portion 47 with respect to the outer fastening boss portion 53o. On the other hand, the first cam holder 16 is also formed with a holder-side protruding portion 26 that protrudes on the side opposite to the first oil passage portion 47 with respect to the wall portion that defines the outer bolt hole 25o. The cap-side protrusion 57 is surface-joined to the holder-side protrusion 26 at the joint surface 20 in a state where the first exhaust cam cap 18 is fastened to the first cam holder 16.

  Thus, since the second oil passage portion 48 and the third oil passage portion 50 are arranged on the same plane orthogonal to the cam shaft direction, the second oil passage portion 48 and the third oil passage portion 48 in the first journal bearing wall 15 are arranged. It is possible to reduce the thickness of the portion that defines the oil passage portion 50, and the engine 1 is prevented from being enlarged in the cam shaft direction. Further, since only the first oil passage portion 47 needs to be formed as the oil passage 40 on the joint surface 20 between the first exhaust cam cap 18 and the first cam holder 16, the width of the joint surface 20 may be reduced. The first exhaust cam cap 18 is compact. Further, since the spool valve 35 is disposed along the first journal bearing wall 15, it is not necessary to increase the thickness of the portion that defines the valve mounting hole 24 for mounting the spool valve 35, and this also increases the engine. 1 is prevented from becoming large.

  As described above, since the VTC actuator 30 is operated only by the hydraulic pressure from the spool valve 35, if the hydraulic pressure becomes insufficient due to oil leakage in the middle of the oil passage 40, the responsiveness deteriorates. In this embodiment, in particular, since the engine 1 is a three-cylinder DOHC engine, the vibration of the engine 1 is large and both the camshafts 9 and 10 are easily bent. Therefore, when the heavy weight VTC actuator 30 is provided at the end of the exhaust camshaft 10, the vibration at the first journal bearing wall 15 near the VTC actuator 30 is large, and the first exhaust cam cap that holds the exhaust camshaft 10. It was necessary to increase the rigidity of 18 in particular. Therefore, in the present embodiment, the outer bolt insertion hole 52o where the first oil passage portion 47 is formed is disposed at a position offset to the side opposite to the retarding annular groove portion 46 to which the first oil passage portion 47 is connected. As a result, it can be arranged in the vicinity of the exhaust camshaft 10. Thereby, the attachment rigidity of the 1st exhaust cam cap 18 increases, and the oil leak from the joining surface 20 in which the 1st oil path part 47 was formed is prevented effectively. In addition, since the first oil passage portion 47 can be disposed obliquely by utilizing a region vacated by the offset of the outer bolt insertion hole 52o in the cam shaft direction, the joint surface 20 is formed to form the first oil passage portion 47. Is suppressed from increasing in the camshaft direction.

  On the other hand, since the outer bolt insertion hole 52o is offset and arranged in the cam shaft direction, the first exhaust cam cap 18 is inclined to the side opposite to the first oil passage portion 47 by the oil pressure of the first oil passage portion 47. Although it becomes easy to cause oil leakage at the joining surface 20, the first cam holder 16 has the holder-side protruding portion 26, and the first exhaust cam cap 18 is joined to the holder-side protruding portion 26. Therefore, the inclination of the first exhaust cam cap 18 due to the hydraulic pressure is prevented, and oil leakage from the gap between the first exhaust cam cap 18 and the first cam holder 16 is suppressed.

  Further, a protruding plate portion 54 is formed to protrude from the fastening boss portion 53o outside the first exhaust cam cap 18 so as to define the first oil passage portion 47, and the height of the protruding plate portion 54 is set to the outside. While the unnecessary height increase is avoided by making the minimum height smaller than the height of the fastening boss portion 53o, the oil pressure of the first oil passage portion 47 is applied to the protruding plate portion 54. The joint surface 20 between the first exhaust cam cap 18 and the first cam holder 16 is opened, and oil leakage is likely to occur. Therefore, in the present embodiment, the rib 55 is provided on the protruding plate portion 54 and connected to the outer fastening boss portion 53o, so that the first exhaust cam cap 18 can be reduced in size and weight while preventing such adverse effects. I am trying. Furthermore, by providing the rib 55 at a position corresponding to the other end 47b of the first oil passage portion 47 where the hydraulic pressure from the second oil passage portion 48 directly acts, it is possible to reliably prevent oil leakage.

  The VTC actuator 30 is provided on the exhaust camshaft 10, and the first oil passage portion 47 is provided on the retarding oil passage 44 side, whereby the advance oil passage 43 is formed on the joining surface 20. Since the first oil passage portion 47 does not pass through the third oil passage portion 50 formed in the first cam holder 16 and reaches the advance angle annular groove portion 49, the advance angle oil passage 43 has a gap from the joint surface 20. There is no oil leakage, and the exhaust camshaft 10 can be quickly and reliably returned to the advanced angle while the engine 1 is stopped or when the engine is started. Is secured.

  In recent years, due to demands for improving fuel consumption and reducing CO 2, further downsizing and weight reduction of the engine 1 have been demanded. With a configuration that does not affect the overall compactness and weight reduction of the engine 1, the rigidity is improved and the VTC actuator 30 is reduced. However, according to this embodiment, this can be achieved by improving the first journal bearing wall 15.

  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, in the above embodiment, the present invention is applied to a four-valve type in-line three-cylinder gasoline engine. However, the present invention can also be applied to other internal combustion engines. Moreover, in the said embodiment, although the cam holder 16 is integrally formed with the cylinder head 6, it can also be set as the form which comprises the cam holder 16 separately from the cylinder head 6. FIG. In addition, the specific configuration, arrangement, and quantity of each device and member can be changed as appropriate without departing from the spirit of the present invention. On the other hand, not all the components of the engine 1 according to the present invention shown in the above-described embodiment are necessarily essential, and can be appropriately selected as long as they do not depart from the gist of the present invention.

1 engine (cam phase variable internal combustion engine)
DESCRIPTION OF SYMBOLS 10 Exhaust cam shaft 15 Journal bearing wall 15X Center line 16 Cam holder 17, 18 Cam cap 19 Bolt 20 Joint surface 21 Oil pump (hydraulic supply source)
25 Bolt hole 26 Holder-side protrusion 30 VTC actuator (cam phase variable device)
33 Hydraulic chamber for advance angle 34 Hydraulic chamber for retard angle 35 Spool valve (hydraulic control valve)
40 oil passage 41 upstream oil passage 43 advance oil passage 44 retard oil passage 46 retard annular groove 47 first oil passage 47a one end of the first oil passage 47b other end of the first oil passage 48 Second oil passage portion 49 Advancing annular groove portion 50 Third oil passage portion 52 Bolt insertion hole 53 Fastening boss portion 54 Projection plate portion 55 Rib 57 Cap side protrusion portion

Claims (6)

A camshaft rotatably supported by a journal bearing wall comprising a cam holder and a cam cap fastened to the cam holder by a bolt;
A cam phase varying device that is provided at an end of the cam shaft and changes the cam phase by supplying hydraulic oil to the advance hydraulic chamber and the retard hydraulic chamber;
A hydraulic control valve that is provided in an oil passage that communicates the hydraulic pressure supply source and the cam phase variable device, and that controls the supply of the hydraulic fluid to the advance hydraulic chamber and the retard hydraulic chamber;
The oil passage includes an upstream oil passage communicating the hydraulic supply source and the hydraulic control valve, an advance oil passage communicating the hydraulic control valve and the advance hydraulic chamber, and the hydraulic control valve. And a retarding oil passage that communicates with the retarding hydraulic chamber, and a variable cam phase internal combustion engine,
The advance angle oil passage has an advance angle annular groove formed annularly on the bearing surface of the journal bearing wall so as to supply the hydraulic oil to the advance angle hydraulic chamber via the camshaft. ,
The retarding oil passage is disposed at a position offset in the camshaft direction with respect to the advancement annular groove so as to supply the hydraulic oil to the retarding hydraulic chamber via the camshaft. It has an annular groove portion for retarding angle formed in the bearing surface,
The hydraulic control valve is disposed along the axis of the journal bearing wall in which the annular groove portion for advancement and the annular groove portion for retardation is formed;
One of the advance angle oil passage and the retard angle oil passage is formed on the joint surface between the cam cap and the cam holder, and one end thereof is connected to the advance angle annular groove portion or the angle delay angle groove portion. A first oil passage and a second oil passage formed in the cam holder and connecting the hydraulic control valve and the other end of the first oil passage;
The other of the advance oil passage and the retard oil passage is formed in the cam holder and is connected to the hydraulic control valve and the advance annular groove portion or the retard annular groove portion. Part
The variable cam phase internal combustion engine, wherein the second oil passage portion and the third oil passage portion are arranged on the same plane orthogonal to the cam shaft direction. The cam cap has a pair of bolt insertion holes through which the bolts are inserted at positions sandwiching the cam shaft,
The bolt insertion hole on one side where the first oil passage portion is formed on the joint surface with the cam holder has the cam shaft direction with respect to the center of the advance angle annular groove portion and the retard angle annular groove portion Arranged at a position offset to the side opposite to the advance angle annular groove portion or the retard angle annular groove portion to which the first oil passage portion is connected;
The other end of the first oil passage portion is located on a side opposite to the camshaft with respect to the bolt insertion hole on the one side in a direction orthogonal to the cam shaft direction. The cam phase variable internal combustion engine described in 1. The cam holder has a pair of bolt holes into which the bolts are screwed at positions corresponding to the pair of bolt insertion holes, and the first oil with respect to a wall portion defining the bolt hole on the one side. It has a holder side protrusion that protrudes on the side opposite to the road part,
The cam cap protrudes on the side opposite to the first oil passage portion with respect to the fastening boss portion defining the one side bolt insertion hole, and a cap side protruding portion joined to the holder side protruding portion The cam phase variable internal combustion engine according to claim 2, characterized by comprising:   From a pair of fastening boss portions that are fastened by the bolts at positions where the cam cap sandwiches the cam shaft, and a fastening boss portion on one side where the first oil passage portion is formed on the joint surface of the cam holder Projecting along the joint surface, projecting on the projecting plate portion defining the first oil passage portion, and on the surface of the projecting plate portion opposite to the joint surface, and connected to the fastening boss portion on the one side. The cam phase variable internal combustion engine according to claim 1, further comprising a rib.   5. The cam phase variable internal combustion engine according to claim 4, wherein the rib is formed to project at a portion of the projecting plate portion corresponding to the other end of the first oil passage portion. The cam phase varying device is provided on the camshaft on the exhaust side,
The cam phase variable internal combustion engine according to any one of claims 1 to 5, wherein the retarding oil passage has the first oil passage portion.

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