JP5758603B2 - Oil supply device for internal combustion engine - Google Patents

Description

  The present invention relates to an oil supply apparatus for an internal combustion engine, and more particularly to an apparatus for supplying drive oil to a variable valve timing mechanism.

  It is known that a variable valve timing mechanism is connected to one end of the camshaft so that the cam phase with respect to the crank phase is variable to make the valve timing variable. The variable valve timing mechanism is generally hydraulic, and an oil passage is formed to supply driving oil to the variable valve timing mechanism.

  In general, an oil passage is formed from the inside of a cylinder head, from an oil control valve, a bearing portion that pivotally supports one end of a camshaft (particularly, an interface portion between an outer peripheral surface of a camshaft and a bearing surface that supports the camshaft) It passes through the inside of one end of the shaft and reaches the variable valve timing mechanism. Patent Document 1 discloses that oil is forcibly supplied to the variable valve timing mechanism by narrowing the oil passage to the hydraulic lash adjuster when the variable valve timing mechanism is operated.

Japanese Utility Model Publication No.5-1804

  In the above-described general configuration, since the oil passage that passes through the bearing portion is formed, the bearing portion becomes longer than the load capacity necessary for the bearing portion, leading to an increase in the length of the bearing portion. As a result, there has been a problem that the total length of the engine becomes longer.

  Accordingly, the present invention has been made in view of such circumstances, and an object of the present invention is to provide an oil supply device for an internal combustion engine that is advantageous in shortening the bearing portion that pivotally supports the camshaft and thus the overall length of the engine.

According to one aspect of the invention,
A camshaft having a variable valve timing mechanism coupled to one end;
An oil passage in the camshaft extending in the axial direction inside the camshaft to supply driving oil to the variable valve timing mechanism;
A valve operating oil passage for supplying oil to the hydraulic lash adjuster or the rocker shaft bearing,
A connecting oil passage connecting the valve operating oil passage and the camshaft oil passage so that oil is supplied to the camshaft oil passage after flowing through the valve oil passage;
An oil supply device for an internal combustion engine is provided.

  According to this configuration, an oil passage that passes through the bearing portion of the camshaft is not necessary, and the bearing portion and thus the engine overall length can be shortened.

Preferably, the oil passage in the camshaft is opened at the other end surface of the camshaft, and the open end forms an inlet end of the oil passage in the camshaft.
The connection oil passage is formed by a connection pipe that connects an outlet end of the valve operating oil passage and an inlet end of the oil passage in the camshaft.

  Preferably, a rolling bearing is provided at the inlet end of the oil passage in the camshaft, and the connection pipe is inserted into the inner diameter surface of the rolling bearing.

  Preferably, an annular member protruding to the other end side of the camshaft and having an enlarged diameter is attached to the other end portion of the camshaft, and a rolling bearing is provided on an inner diameter surface of the annular member. The connecting pipe is inserted into the inner diameter surface.

  Preferably, the annular member includes a sensor ring for detecting the phase of the camshaft.

  Preferably, the inner ring of the rolling bearing is provided with a labyrinth portion that protrudes to one end side and is close to the inner peripheral surface of the inlet end portion of the oil passage in the camshaft.

  Preferably, a part of the connection oil passage is located at a position higher than the highest position of the camshaft oil passage.

  According to the present invention, it is possible to provide an excellent effect that an oil supply device for an internal combustion engine that is advantageous in shortening a bearing portion that supports a camshaft and thus an overall engine length can be provided.

It is a perspective view which shows the oil supply apparatus of the internal combustion engine which concerns on embodiment of this invention. It is a disassembled perspective view which shows the structure of the engine main body above a cylinder block. It is sectional drawing which shows the structure of the drive mechanism for driving an intake valve. It is sectional drawing of a rocker arm. It is sectional drawing which shows the oil-path structure for supplying drive oil to a variable valve timing mechanism. It is a schematic perspective view which shows the variable valve timing mechanism in an advance angle state. It is a schematic perspective view which shows the variable valve timing mechanism in a retarded state. It is a perspective view which shows the sensor ring and cam position sensor of a camshaft rear end part. It is sectional drawing which shows the oil-path structure of a comparative example. It is sectional drawing which shows a 1st modification. It is sectional drawing which shows a 2nd modification. It is sectional drawing which shows a 3rd modification. It is a figure which shows the inner ring | wheel of a 3rd modification. It is a figure which shows the alternative inner ring | wheel of a 3rd modification. It is sectional drawing which shows the oil-path structure of a 4th modification.

  DESCRIPTION OF EMBODIMENTS Hereinafter, embodiments for carrying out the present invention will be described with reference to the accompanying drawings.

  FIG. 1 shows an oil supply apparatus for an internal combustion engine according to the present embodiment. The oil flow in this apparatus is indicated by arrows in the figure. The internal combustion engine of the present embodiment is a vehicle in-line 4-cylinder 4-valve engine.

  As illustrated, the internal combustion engine (engine) 1 includes an oil pump 2 driven by a crankshaft CR. The oil pump 2 sucks the oil stored in the oil pan 3 through the oil strainer 4 and discharges the oil toward the oil filter 5. The oil that exits the oil filter 5 flows into a main oil hole 7 that extends in the crankshaft direction of the cylinder block 6.

  The oil is distributed from the main oil hole 7 to each part. For example, the oil is distributed to the oil delivery pipe 10 disposed at the uppermost part in the valve operating chamber R defined by the cylinder head 8 and the head cover 9. The oil in the oil delivery pipe 10 is supplied dropwise to a plurality of positions in the longitudinal direction of the intake camshaft 20 and the exhaust camshaft 21.

  The oil in the main oil hole 7 is distributed to a plurality of crank journals 12, a crankpin (not shown), an oil jet 13, and a chain tensioner 14 that support the crankshaft.

  Further, the oil in the main oil hole 7 is supplied to a hydraulic lash adjuster (hereinafter referred to as HLA) 16 provided in each cylinder. This supply is performed through an HLA oil passage 15 (corresponding to a valve operating oil passage of the present invention) extending in the longitudinal direction inside the cylinder head 8. One HLA oil passage 15 is provided on each of the intake side and the exhaust side, and extends substantially along the entire length of the engine body. Here, the engine body refers to a structure or housing of the engine 1, that is, a structure including the cylinder block 6, the cylinder head 8, the crankcase 11, the head cover 9, and the oil pan 3. The HLA 16 is provided in the same number as the intake valve Vi and the exhaust valve Ve per cylinder. In this embodiment, two HLAs 16 are provided on the intake side and two on the exhaust side per cylinder.

  FIG. 2 shows the structure of the engine body above the cylinder block 6. The cylinder head 8 is generally configured by being divided into a lower cylinder head main body 8A and an upper cam housing 8B. A camshaft bearing cap 8C is fastened to the cam housing 8B from above by a bolt (not shown). A cylinder head gasket 17 is interposed between the fastening surface of the cylinder head body 8 </ b> A and the cylinder block 6. A cylinder head cover gasket 18 is interposed between the fastening surfaces of the cylinder head 8 and the head cover 9.

  FIG. 3 shows a configuration of a drive mechanism for driving one intake valve Vi. This drive mechanism is provided for each of the intake valve Vi and the exhaust valve Ve.

  In the cylinder head body 8A, an intake port 19 is formed, and an intake valve Vi that opens and closes the outlet of the intake port 19 is provided so as to be movable up and down. The intake valve Vi is urged by the valve spring 22 in the valve closing direction or the upward direction. The intake camshaft 20 is opened by pushing down the intake valve Vi via the rocker arm 23. The rocker arm 23 rotates using the engaging portion with the HLA 16 as a fulcrum. As the rocker arm 23, a roller rocker arm as shown in FIG. 4 is used. The rocker arm 23 includes a roller support shaft 24, a plurality of rollers 25, and an outer ring 26 as a contact ring, and constitutes a rocker shaft bearing portion. An HLA oil passage 15 is formed inside the cylinder head body 8 </ b> A adjacent to the HLA 16.

  FIG. 5 shows an oil passage structure for supplying driving oil to the variable valve timing mechanism 30. The longitudinal direction or the axial direction of the intake camshaft 20 that is the left-right direction in the drawing is also simply referred to as the longitudinal direction or the axial direction. The left side of the drawing is one end side of the intake camshaft 20, and this one end side is the front end side. The right side of the figure is the other end side of the intake camshaft 20, and this other end side is the rear end side.

  In the present embodiment, the variable valve timing mechanism 30 is provided only on the intake side. However, it is also possible to provide a variable valve timing mechanism on the exhaust side and employ an oil passage structure similar to that on the intake side.

  The intake camshaft 20 (hereinafter also simply referred to as a camshaft) has a front end piece 27 at its front end, and a variable valve timing mechanism (hereinafter referred to as VVT) 30 is coaxially connected to the front end piece 27. The VVT 30 is fastened to the front end piece 27 by a bolt-integrated oil control valve (hereinafter referred to as OCV) 31. The camshaft 20 is pivotally supported by needle bearings 32 as rolling bearings at a plurality of positions along the longitudinal direction (particularly, positions before and after each cylinder). The needle bearing 32 is sandwiched between the lower cam housing 8B and the upper camshaft bearing cap 8C.

  In particular, the front end wall 8Bf of the cam housing 8B located at the forefront and the front end camshaft bearing cap 8Cf combined with the front end wall 8Bf are front end bearing portions that support the front end piece 27 via the front end needle bearing 32f ( The so-called # 1 journal) B1 is formed, and the front end wall of the engine body is also formed. The front end needle bearing 32f includes an outer ring 32f1, an inner ring 32f2, and a plurality of rollers 32f3.

  At locations other than the front end portion, a bearing portion in which a lower bearing wall 8Bl of the cam housing 8B and a camshaft bearing cap 8C combined with the lower bearing wall 8Bl support the intake camshaft 20 via a needle bearing 32. B is formed. In the rear end portion shown on the right side in the drawing, the rear end wall 8Br of the cam housing 8B is erected further rearward than the rearmost bearing portion B, and this rear end wall 8Br forms the rear end wall of the engine body. The needle bearing 32 has an outer ring 321 and a plurality of rollers 323, and does not have an inner ring.

  The intake camshaft 20 of the present embodiment is generally configured by attaching the front end piece 27 and a plurality of cam lobes 20B to a camshaft main body 20A made of a hollow pipe having a constant inner and outer diameter by press fitting or the like. The front end portion of the camshaft main body 20A is coaxially inserted and fixed in the shaft hole 28 of the front end piece 27 by press fitting or the like. The front end piece 27 is provided with a flange 29 for sealing or the like adjacent to the front end wall 8Bf and the rear surface of the front end camshaft bearing cap 8Cf. A bolt hole 32 for mounting the OCV 31 is also provided on the front end piece 27 coaxially.

  As shown in FIG. 6, the VVT 30 is generally composed of a cam sprocket 33 and a vane 34 that can rotate relative to each other. The cam sprocket 33 forms a housing of the VVT 30 and has a sprocket 35. The sprocket 35 is connected to the crankshaft CR by a timing chain, and the cam sprocket 33 rotates in synchronization with the crankshaft. The vane 34 is substantially fixed to the front end piece 27, that is, the camshaft 20, and rotates in synchronization with the camshaft 20.

  An advance side hydraulic chamber 36 as shown in FIG. 6 and a retard side hydraulic chamber 37 as shown in FIG. 7 are formed between the cam sprocket 33 and the vane 34. As shown in FIG. 6, when driving oil or hydraulic pressure is supplied to the advance side hydraulic chamber 36 and the hydraulic pressure is discharged from the retard side hydraulic chamber 37, the vane 34 rotates toward the advance side with respect to the cam sprocket 33. The camshaft 20 is advanced with respect to the crankshaft. On the other hand, as shown in FIG. 7, when the hydraulic pressure is supplied to the retard angle side hydraulic chamber 37 and the hydraulic pressure is discharged from the advance angle side hydraulic chamber 36, the vane 34 is rotated to the retard angle side with respect to the cam sprocket 33, The camshaft 20 is retarded with respect to the crankshaft.

  As shown in FIG. 5, the front end piece 27 has a supply oil passage 38 for flowing the driving oil supplied to the VVT 30, and a drain oil passage for flowing the oil discharged from the VVT 30 into the valve operating chamber R. 39 is formed. The inlet end of the supply oil passage 38 is communicated with the shaft hole 28. The supply oil passage 38 extends substantially in the axial direction of the front end piece 27. For convenience of processing, a part of the supply oil passage 38 is opened in the outer peripheral surface of the front end piece 27, but this opening is closed by the inner ring 32f2 of the front end needle bearing 32f.

  Although not shown, the OCV 31 is equipped with an electromagnetic spool valve for switching the oil passage, and this electromagnetic spool valve is controlled to be switched by an engine control unit (ECU). The first oil passage 40 connecting the supply oil passage 38 of the front end piece 27 and the inlet port of the OCV 31, the second oil passage 41 connecting the first port of the OCV 31 and the advance side hydraulic chamber 36 of the VVT 30, and the second port of the OCV 31 And a fourth oil passage 43 connecting the outlet port of the OCV 31 and the drain oil passage 39 of the front end piece 27 are formed in the VVT 30 or the OCV 31, respectively. Yes.

  By the way, the hole in the axial center portion of the camshaft main body 20A forms the main body oil passage 44. The oil passage 44 in the main body, the oil passage 38 and the shaft hole 28 extend in the camshaft 20 in the axial direction so as to supply driving oil to the VVT 30. Configure. The main body oil passage 44 is connected to the HLA oil passage 15 via the connection oil passage 45 so that the oil flows through the HLA oil passage 15 and then is supplied to the main body oil passage 44 and thus to the camshaft oil passage. It has become. The oil flow is indicated by arrows in the figure. The body oil passage 44 is located downstream of the HLA oil passage 15.

  The body oil passage 44 is opened at the rear end surface of the camshaft 20. The open end serves as an inlet end of the main body oil passage 44 or the camshaft inner oil passage. The supply oil passage 38 is opened at the front end face of the front end piece 27. The open end forms the outlet end of the supply oil passage 38 or the oil passage in the camshaft. After all, the camshaft oil passage extends over the entire length of the camshaft 20.

  The HLA oil passage 15 is opened on the outer wall surface of the cylinder head 8 </ b> A, particularly the rear end surface, and the open end forms the outlet end of the HLA oil passage 15.

  The connection oil passage 45 is formed by a substantially U-shaped or U-shaped connection pipe 46 that opens to the front and connects the outlet end of the HLA oil passage 15 and the inlet end of the in-body oil passage 44. The connecting pipe 46 is exposed to the outside. An inlet end 46A of the connecting pipe 46 located below is press-fitted into the HLA oil passage 15 and fixed. The connecting pipe 46 is bent upward immediately after leaving the HLA oil passage 15 and further bent forward at the height position of the camshaft 20.

  The upper portion 46B of the connecting pipe 46 is inserted through the hole 47 of the cam housing rear end wall 8Br, and the outlet end portion 46C of the connecting pipe 46 is inserted coaxially into the oil passage 44 in the main body. An oil seal 48 is provided in the hole 47 of the rear end wall 8Br of the cam housing, and an oil seal 49 for sealing a clearance from the outlet end portion 46C of the connection pipe 46 is also provided at the inlet end portion of the oil passage 44 in the main body. Provided. The connection pipe 46 is fixed to the rear end wall of at least one of the cylinder head body 8A and the cam housing 8B from the outside by a bracket or the like (not shown). FIG. 3 also shows the connecting pipe 46 virtually.

  The inner diameter of the oil seal 49 at the inlet end of the body oil passage 44 is smaller than the inner diameter of the outlet end portion of the HLA oil passage 15, so that the connecting pipe 46 is between the inlet end portion 46A and the outlet end portion 46C. Thus, the diameter is reduced gradually or stepwise as shown.

  Note that the configuration related to the connection pipe 46 and the connection oil passage 45 is not limited to the above-described configuration, and a flange, a hydraulic coupling, or the like may be used for connection between the connection pipe 46, the HLA oil passage 15, and the main body oil passage 44. . A flexible hose may be used for the connection pipe 46. The connecting pipe 46 may be provided inside the engine body and not exposed to the outside.

  As shown in FIG. 5, a sensor ring 50 for detecting the phase of the camshaft 20 is attached to the rear end portion and the outer peripheral surface portion of the camshaft 20. As shown in FIG. 8, the sensor ring 50 is used in combination with a non-contact cam position sensor 51 fixed to the head cover 9. The sensor ring 50 has a plurality of protrusions intermittently in the rotation direction, and the cam position sensor 51 detects the protrusions to detect the rotation phase of the camshaft 20.

  As shown in FIG. 5, the oil that has flowed through the HLA oil passage 15 from the front to the rear is then introduced into the connection oil passage 45, rises along the connection oil passage 45, and is supplied to the main body oil passage 44. The Then, the oil flows from the rear to the front through the oil passage 44 in the main body, and enters the shaft hole 28 of the front end piece 27 where the outlet end of the oil passage 44 in the main body is opened. Thereafter, the oil is supplied to the inlet port of the OCV 31 through the supply oil passage 38 and the first oil passage 40.

  On the other hand, the oil discharged from the outlet port of the OCV 31 is discharged to the valve operating chamber R through the fourth oil passage 43 and the drain oil passage 39 of the front end piece 27.

  In the present embodiment, a rolling bearing is used for the bearing portion of the camshaft 20 instead of a general journal bearing (or plain bearing). For this reason, the positive oil supply to a bearing part is unnecessary, and the oil path (circumferential groove etc.) for supplying oil to a bearing part is not provided. Oil supply to the rolling bearing is performed by an oil mist or the like in the atmosphere.

  Next, advantages of the present embodiment will be described in comparison with the comparative example shown in FIG. This comparative example has a structure closer to a general structure than the above embodiment. The front end piece 27 is provided with a circumferential groove 101, and driving oil is supplied to the circumferential groove 101 from an oil passage 102 formed inside the cam housing front end wall 8Bf. The oil in the circumferential groove 101 is supplied to the first oil passage 40 and the inlet port of the OCV 31 through the supply oil passage 103 formed in the front end piece 27.

  In order to prevent the oil in the circumferential groove 101 from leaking forward, a ring-shaped seal portion 104 protruding radially outward is provided in the front end piece 27 in front of the circumferential groove 101 and between the front end needle bearing 32f. Provided. Similarly, in order to prevent the oil in the circumferential groove 101 from leaking backward, a ring-shaped seal portion 105 protruding outward in the radial direction is provided on the front end piece 27 behind the circumferential groove 101. In this comparative example, the space in the camshaft main body 20A is not used as an oil passage. Other configurations are the same as those of the above-described embodiment, and the same components are denoted by the same reference numerals in the drawings.

  Note that this comparative example has a configuration as close as possible to the above-described embodiment for easy understanding. However, a more general configuration that is further away from the embodiment may be employed. For example, the bearing may be a journal bearing instead of a rolling bearing, and the camshaft may not be a camshaft made of a hollow pipe but may be a more general cast product. The circumferential groove may be provided not on the front end piece side but on the bearing side.

  In the case of this comparative example, since the driving oil is supplied from the oil passage 102 of the cam housing front end wall 8Bf to the supply oil passage 103 of the front end piece 27, the circumferential groove 101 and the seal portions 104, 105 is essential. Therefore, the front end bearing portion B1 becomes longer than the necessary load capacity. The front end bearing portion B1 is longer than that in the above embodiment, and in the illustrated example, the position of the front end is in front of the above embodiment by ΔL. For this reason, the overall length of the engine also becomes longer.

  Further, the processing cost of the circumferential groove 101 and the material cost due to the increase in the length of the front end bearing portion B1 are added, which is disadvantageous in terms of cost. Furthermore, the method of changing the oil flow direction by 90 ° from the radial direction to the axial direction via the circumferential groove 101 may cause an increase in pressure loss.

  On the other hand, in the case of the present embodiment shown in FIG. 5, the oil in the HLA oil passage 15 is supplied to the main body oil passage 44 via the connection oil passage 45, and the supply oil of the front end piece 27 is supplied from the main body oil passage 44. Oil is supplied to the passage 38. For this reason, the circumferential groove 101 as the oil passage and the seal portions 104 and 105 as in the comparative example are unnecessary, and the front end bearing portion B1 can be shortened to a length corresponding to the required load capacity. For this reason, it is possible to shorten the engine overall length.

  Moreover, since the processing of the circumferential groove 101 is unnecessary and the material cost can be suppressed by shortening the front end bearing portion B1, it is advantageous in terms of cost. Furthermore, since the oil can flow almost straight in the axial direction from the oil passage 44 in the main body to the supply oil passage 38 of the front end piece 27, it is advantageous in reducing pressure loss.

  Thus, according to the above-described embodiment, it is possible to provide an oil supply device for an internal combustion engine that is advantageous for shortening the bearing portion that supports the camshaft and thus the overall length of the engine.

  Next, a modification of the embodiment (hereinafter referred to as a basic embodiment) will be described.

  FIG. 10 shows a first modification. In the first modification, a ball bearing 60 with a seal as a rolling bearing is provided at the inlet end of the oil passage 44 in the main body at the rear end of the camshaft 20. The outlet end 46 </ b> C of the connection pipe 46 is inserted into the inner diameter surface 601 of the ball bearing 60. An outlet end portion 46 </ b> C of the connection pipe 46 is pivotally supported by the rear end portion of the camshaft 20 via a ball bearing 60.

  The ball bearing 60 includes an outer ring 602, an inner ring 603, a plurality of balls 604, and seal members 605 in the axial direction. An O-ring 61 as a seal member is provided between the inner diameter surface 601 of the inner ring 603 and the outer diameter surface 46D of the outlet end portion 46C of the connection pipe 46. In the illustrated example, a groove for positioning the O-ring 61 in the axial direction is provided on both the inner diameter surface 601 and the outer diameter surface 46D, but may be provided on either one.

  In the basic embodiment, the seal ring 49 as a simple seal member is provided in the gap between the camshaft 20 and the connection pipe 46 in the insertion portion. For this reason, it cannot be denied that sliding resistance and rotational resistance increase when the camshaft 20 rotates. In addition, since the seal ring 49 slides with respect to the connecting pipe 46, there is a concern that the seal ring 49 may deteriorate early.

  On the other hand, in the first modification, a ball bearing 60 is provided in the gap. For this reason, it is possible to reduce sliding resistance and rotational resistance when the camshaft 20 rotates. Further, since the sliding portion is substantially only between the members inside the ball bearing, the durability can be greatly improved.

  FIG. 11 shows a second modification. In the second modification, the structure of the sensor ring 50A attached to the rear end portion of the camshaft 20 is different from that of the basic embodiment.

  That is, the sensor ring 50 </ b> A is made of a sheet metal press, and is attached to the outer peripheral surface of the rear end portion of the camshaft 20, the mounting pipe portion 65 is positioned behind the mounting pipe portion 65, and the mounting pipe portion 65. The support tube portion 66 having a larger diameter than the support tube portion 66 and an annular sensor portion 67 that is located behind the support tube portion 66 and has a diameter larger than that of the support tube portion 66 are integrally provided. A plurality of teeth are intermittently formed in the circumferential direction in the sensor portion 67, and the sensor portion 67 forms a portion detected by the cam position sensor 51.

  When the sensor ring 50 </ b> A is attached to the rear end portion of the camshaft 20, the support tube portion 66 and the sensor portion 67 protrude rearward from the camshaft 20 and are expanded in diameter. A ball bearing 68 with a seal as a rolling bearing is provided on the inner diameter surface 66 </ b> A of the support tube portion 66. The outlet end 46 </ b> C of the connection pipe 46 is inserted into the inner diameter surface 681 of the ball bearing 68. An outlet end portion 46C of the connection pipe 46 is pivotally supported by the sensor ring 50A via a ball bearing 68.

  Similar to the first modification, the ball bearing 68 includes an outer ring 682, an inner ring 683, a plurality of balls 684, and axially front and rear seal members 685. An O-ring 69 as a seal member is provided between the inner diameter surface 681 of the inner ring 683 and the outer diameter surface 46D of the outlet end portion 46C of the connection pipe 46. In the illustrated example, the groove for positioning the O-ring 69 in the axial direction is provided only on the outer diameter surface 46D, but may be provided only on the inner diameter surface 681 or both.

  According to the second modified example, the ball bearing 68 is provided on the support pipe portion 66 that is rearward and larger in diameter than the rear end portion of the camshaft 20, and the outlet end portion 46 </ b> C of the connection pipe 46 is provided on the ball bearing 68. Insertion supported. For this reason, compared with the first modification, the inner and outer diameters of the ball bearing 68 and, in turn, the outer diameter of the outlet end portion 46C of the connection pipe 46 can be increased.

  Therefore, a ball bearing 68 having a more general size can be used, and the cost of the ball bearing 68 can be reduced. In addition, it is possible to use a connection pipe 46 having a constant diameter in which the outer diameters of the inlet end portion 46A and the outlet end portion 46C are equal, and the cost of the connection pipe 46 can be reduced.

  The connecting pipe 46 can be formed of the same pipe material as that of the camshaft main body 20A. In this case, further cost reduction can be achieved. Further, if the HLA oil passage 15 is defined by a pipe material, and this pipe material is also formed by the same pipe material as the connection pipe 46 and the camshaft main body 20A, the cost can be further reduced.

  In the second modification, the sensor ring 50A corresponds to the annular member of the present invention. However, the annular member is not necessarily shared with the sensor ring. An annular member may be provided only for attaching the connecting pipe 46. Of course, if the annular member is shared with the sensor ring, it is needless to say that cost reduction can be achieved by reducing the number of parts. The annular member or the sensor ring may not be made of a sheet metal press, and may be a cast product, for example.

  FIG. 12 shows a third modification. In the third modification, the structure of the inner ring 683 of the ball bearing 68 is changed with respect to the configuration of the second modification.

  That is, the inner ring 683 is provided with a labyrinth portion 70 that protrudes forward and is close to the inner peripheral surface of the inlet end portion of the main body inner oil passage 44 (that is, the inner diameter surface of the camshaft main body 20A). That is, the axial width of the inner ring 683 including the labyrinth portion 70 is larger than the axial width of the outer ring 682.

  FIG. 13 shows the appearance of the inner ring 683. As can be seen, a plurality of labyrinth grooves 71 perpendicular to the axial direction are provided on the outer peripheral surface of the labyrinth portion 70. Reference numeral 72 denotes a groove for positioning the O-ring 69. Alternatively, as shown in FIG. 14, a spiral labyrinth groove 71A may be provided. It is preferable that the minimum clearance between the labyrinth portion 70 and the inner peripheral surface of the main body oil passage 44 to which the labyrinth portion 70 is opposed is 0.1 mm or less.

  According to the third modification, the hydraulic pressure applied to the seal member 685 on the front side of the ball bearing 68 can be reduced due to the presence of the labyrinth portion 70. For this reason, it is possible to reduce sliding resistance and rotational resistance when the camshaft 20 rotates.

  FIG. 15 shows a fourth modification. In the fourth modification, the configurations of the connection oil passage 45 and the connection pipe 46 are changed with respect to the configuration of the basic embodiment. That is, a part of the connection oil passage 45 is located at a position higher than the highest position of the camshaft oil passage.

  More specifically, the connecting pipe 46 is bent so as to have a portion higher than the insertion position to the rear end portion of the camshaft. In the connection pipe 46, the upper part 46B is bent upward immediately after coming out of the hole 47 of the cam housing rear end wall 8Br, and further bent into a U-shape. In this way, the connection pipe 46 is provided with a U-shaped top portion 46D that opens downward. The highest position H2 on the in-corner side of the inner surface of the top portion 46D is higher than the highest position H1 of the oil passage 44 in the main body. The highest position H2 is higher than the highest position H3 of the supply oil passage 38 of the front end piece 27. Thereby, the highest position H2 is set to a position higher than the highest position of the oil passage in the camshaft.

  According to this configuration, when the engine is stopped, the oil in the camshaft oil passage, particularly the oil in the main body oil passage 44, can be prevented from flowing back to the HLA oil passage 15 through the connection oil passage 45 due to gravity, dropping and returning. That is, the oil can be held in the oil passage 44 in the main body when the engine is stopped, and the oil can be quickly supplied to the VVT 30 when the engine is subsequently started, so that the VVT 30 can be started early.

  The configuration of the fourth modification can also be applied to the first to third modifications.

  The preferred embodiments of the present invention have been described in detail above, but various other embodiments of the present invention are conceivable. For example, the use and type of the internal combustion engine are arbitrary. The kind of rolling bearing is also arbitrary.

  Instead of the HLA oil passage 15, an oil passage for supplying oil to the rocker shaft bearing portion may be used as the valve operating oil passage. That is, there is a rocker arm of a type that rotates while being supported by a fixed rocker shaft. In this structure, an oil passage extending in the longitudinal direction is formed to supply oil to the rocker shaft bearing portion of each cylinder. Since this oil passage has the same characteristics as the HLA oil passage 15, it can be suitably employed as a valve operating oil passage.

  The embodiment of the present invention is not limited to the above-described embodiment, and includes all modifications, applications, and equivalents included in the concept of the present invention defined by the claims. Therefore, the present invention should not be construed as being limited, and can be applied to any other technique belonging to the scope of the idea of the present invention.

1 Internal combustion engine 16 Hydraulic lash adjuster (HLA)
20 Intake camshaft 30 Variable valve timing mechanism (VVT)
44 Body oil passage 45 Connection oil passage 46 Connection pipe 46D Top 50, 50A Sensor ring 60 Ball bearing 601 Inner surface 66 Support tube portion 66A Inner surface 68 Ball bearing 681 Inner surface 683 Inner ring 70 Labyrinth portion

Claims (6)

A camshaft having a variable valve timing mechanism connected to the front end ;
An oil passage in the camshaft extending in the axial direction inside the camshaft to supply driving oil to the variable valve timing mechanism;
A valve operating oil passage for supplying oil to the hydraulic lash adjuster or the rocker shaft bearing,
A connecting oil passage connecting the valve operating oil passage and the camshaft oil passage so that oil is supplied to the camshaft oil passage after flowing through the valve oil passage;
With
The camshaft includes a front end piece disposed at a front end of the camshaft, and a hollow camshaft body that is coaxially inserted and fixed in a shaft hole of the front end piece, and the variable valve timing mechanism is provided at the front end of the front end piece. Are connected coaxially,
A supply oil path for flowing oil supplied to the variable valve timing mechanism is formed in the front end piece, and the supply oil path extends in an axial direction of the front end piece,
A hole in the axial center portion of the camshaft body forms an oil passage in the main body, and the supply oil passage, the shaft hole, and the oil passage in the main body communicate with each other to constitute the oil passage in the camshaft.
The oil flows through the oil passage in the main body from the rear to the front, enters the shaft hole where the outlet end of the oil passage in the main body opens, and then is supplied to the variable valve timing mechanism through the supply oil passage. Configured,
Said body oil passage is open at an end plane of said cam shaft, said open ends, without an inlet end for introducing oil to the oil passage within the camshaft,
The connection oil passage is formed by a connection pipe that connects an outlet end of the valve operating oil passage and an inlet end of the oil passage in the camshaft.
The internal combustion engine is configured so that oil flows through the connection oil passage formed by the connection pipe in a direction from an outlet end of the valve operating oil passage toward an inlet end of the oil passage in the camshaft. Engine oil supply device. 2. The oil supply apparatus for an internal combustion engine according to claim 1, wherein a rolling bearing is provided at an inlet end of the oil passage in the camshaft, and the connecting pipe is inserted into an inner diameter surface of the rolling bearing. An annular member that protrudes to the rear end side of the camshaft and has an enlarged diameter is attached to the rear end portion of the camshaft, and a rolling bearing is provided on the inner diameter surface of the annular member. The oil supply device for an internal combustion engine according to claim 1, wherein the connection pipe is inserted. The oil supply device for an internal combustion engine according to claim 3, wherein the annular member includes a sensor ring for detecting a phase of the camshaft. 5. The internal combustion engine according to claim 3, wherein the inner ring of the rolling bearing is provided with a labyrinth portion that protrudes toward a front end side and is close to an inner peripheral surface of an inlet end portion of the oil passage in the camshaft. Oil supply device. The oil supply device for an internal combustion engine according to any one of claims 1 to 5, wherein a part of the connection oil passage is located at a position higher than a highest position of the oil passage in the camshaft.

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