JP2010242539A - Internal combustion engine with valve lubricating structure - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To stabilize an amount of oil supplied to a contact part to improve lubricity at the contact part, in valve lubricating structure for an internal combustion engine supplying lubricating oil supplied to a cam holder rotatably supporting a camshaft to contact part between an engine valve and a cam follower. <P>SOLUTION: The internal combustion engine with valve gear includes: valve lubricating structure 70 lubricating the contact part Ci where a drive rocker arm 45a is in contact with an intake valve 21. The lubricating structure 70 is constituted of: an oil supply path 71 having an inlet 71i opened to the inside of a bearing hole 56 of the cam holder 50 where a journal part 41a of an intake camshaft 41 is arranged, and leading the lubricating oil in the bearing hole 56 to vertically above an upper surface 27 of a retainer 23; and a retainer 23 leading the lubricating oil dropped from an outlet 71o of the oil supply path 71 to the contact part Ci. The oil supply path 71 is positioned below a top part of the bearing hole 56 from the inlet 71i to the outlet 71o. <P>COPYRIGHT: (C)2011,JPO&INPIT

Description

  The present invention relates to a lubricating structure for operating a valve of an internal combustion engine, which includes an engine valve that is an intake valve and an exhaust valve, and a valve operating device that opens and closes the engine valve. The present invention relates to a lubrication structure for a valve train for lubricating a contact portion with a cam follower.

  A cam holder for rotatably supporting a camshaft at a contact portion between a rocker arm, which is a cam follower driven by a valve cam of a camshaft, and an engine valve in a lubricating structure for valve actuation of an internal combustion engine including an engine valve and a valve operating device That supply the lubricating oil from the engine (see, for example, Patent Document 1) and those that supply the lubricating oil to the contact portion between the rocker arm and the valve cam (for example, see Patent Document 2) are known.

JP 2004-293435 A Japanese Patent Publication No.7-116925

In a lubricating structure in which lubricating oil is supplied from the cam holder to the contact portion between the rocker arm and the engine valve, the lubricating oil in the bearing hole of the cam holder in which the journal portion of the cam shaft is arranged is guided upward from the bearing hole, and the cam holder When the oil is supplied to the contact portion through an oil supply groove provided on the upper surface of the cam holder or an oil supply groove provided outside the cam holder, the lubricating oil in the bearing hole is higher than the bearing hole. Therefore, it is necessary to increase the oil pressure of the lubricating oil in the bearing hole, so that the amount of oil supplied to the contact portion is easily affected by the oil pressure of the lubricating oil in the bearing hole, and the oil pressure fluctuation causes a low oil pressure. When this happens, it may be difficult to ensure a sufficient amount of oil at the contact site.
In addition, once the lubricating oil in the bearing hole has flowed out of the cam holder to the outside, the oil supply groove formed on the outer surface or outside of the cam holder is allowed to flow down. In the case of an internal combustion engine, the lubrication oil in the lubrication groove tends to jump out of the lubrication groove until it reaches the outlet of the lubrication groove due to vibrations and running conditions that occur as the vehicle travels, It may be difficult to secure a sufficient amount of oil.
On the other hand, when the lubricating oil is injected from the oil supply pipe toward the contact portion, the amount of oil supplied to the contact portion is easily affected by the hydraulic pressure. For this reason, if it is going to supply the lubricating oil in the part from which the stable oil_pressure | hydraulic is obtained to an oil supply pipe, arrangement | positioning of an oil supply pipe will be restrict | limited, and the compact arrangement | positioning of an oil supply pipe or an oil supply path will become difficult.

  The present invention has been made in view of such circumstances, and a valve for an internal combustion engine that supplies lubricating oil supplied to a cam holder that rotatably supports a cam shaft to a contact portion between the engine valve and the cam follower. It is an object of the present invention to improve the lubricity at the contact site by stabilizing the amount of oil supplied to the contact site.

The invention according to claim 1 is a valve device (20) comprising an engine valve (21) and a retainer (23) for holding a valve spring (22) for biasing the engine valve (21) in the valve closing direction; A cam shaft (41) rotatably supported by the cam holder (50), and a cam follower (45a) that is driven by a valve cam (43) of the cam shaft (41) to open and close the engine valve (21). An internal combustion engine including a valve operating device (40) including a valve operating lubrication structure (70) for lubricating a contact portion (Ci) where the engine valve (21) and the cam follower (45a) are in contact with each other is provided. The lubrication structure (70) has an inlet (71i) that opens into a bearing hole (56) of the cam holder (50) in which the journal portion (41a) of the cam shaft (41) is disposed, and the bearing Lubricating oil (71) for guiding the lubricating oil in the hole (56) vertically above the upper surface (27) of the retainer (23) And the retainer (23) for guiding the lubricating oil dropped from the outlet (71o) of the oil supply passage (71) to the contact portion (Ci), the oil supply passage (71) being the inlet (71i) The internal combustion engine is located below the uppermost portion of the bearing hole (56) from the outlet to the outlet (71o).
According to a second aspect of the present invention, in the internal combustion engine according to the first aspect, the oil supply passage (71) communicates with a holder hole (81) provided in the cam holder (50) and the holder hole (81). The oil supply pipe (82) is connected to the cam holder (50) as described above, and the oil supply pipe (82) is bent vertically downward so that the outlet (71o) opens vertically downward. It has a pipe part (82b).
According to a third aspect of the present invention, in the internal combustion engine according to the first or second aspect, the upper surface (27) is inclined with respect to a horizontal plane, and the contact portion (Ci) and the outlet (71o) are provided on the cam. The outlet (71o) is at a position intersecting with the plane (P2) perpendicular to the cam center line (Li) of the shaft (41), and the outlet (71o) faces upward from the contact part (Ci) in the inclined direction (A). It is located closer to the tilt direction (A1).
According to a fourth aspect of the present invention, in the internal combustion engine according to any one of the first to third aspects, the journal surface (55) is in sliding contact with the bearing surface (55) of the bearing hole (56). A journal oil passage (65) is provided between the journal surface (41b) of 41a), and the inlet (71i) is connected to the journal oil passage (65) in the axial direction of the cam shaft (41). The oil supply groove (72) provided adjacent to the bearing surface (55) or the journal surface (41b) is opened.
According to a fifth aspect of the present invention, in the internal combustion engine according to any one of the first to fourth aspects, the lubricating oil in the oil supply passage (71) moves the oil supply passage (71) from the inlet (71i). It flows without going upward until it reaches the exit (71o).

According to the first aspect of the present invention, the oil supply passage for guiding the lubricating oil in the bearing hole of the cam holder to the contact portion does not need to guide the lubricating oil above the uppermost portion of the bearing hole from the inlet to the outlet. In addition, since the lubricating oil in the bearing hole can be guided to the outlet by using gravity, the lubricating oil in the bearing hole is supplied to the contact portion as compared with the lubricating structure for a valve train that guides the lubricating oil in the bearing hole to the upper surface of the cam holder. The amount of lubricating oil is less susceptible to fluctuations in the hydraulic pressure of the lubricating oil in the bearing hole. As a result, in the valve train lubrication structure, the amount of oil supplied to the contact site is stabilized, so that the required amount of oil can be secured stably and the lubricity at the contact site is improved.
According to the second aspect of the present invention, the oil supply passage is an oil passage having a closed cross section from the inlet to the outlet, so that the oil supply passage is formed by a groove and is an oil passage having an open cross section. Further, it is possible to prevent the lubricating oil in the oil supply path from jumping out of the oil supply path before reaching the outlet due to the vibration of the internal combustion engine or the like. Further, the lubricating oil in the oil supply passage can be concentrated on the upper surface of the retainer and efficiently dropped by the bent pipe portion bent vertically downward and the outlet opened downward vertically. As a result, the amount of oil supplied to the contact site is stabilized, so that the lubricity at the contact site is improved.
According to the third aspect of the present invention, the lubricating oil that has dropped or dropped from the oil supply passage onto the upper surface of the retainer (23) flows downwardly in an inclined direction toward the contact portion on the upper surface. As a result, the amount of lubricating oil flowing down the upper surface and supplied to the contact site is stabilized, so that the lubricity at the contact site is improved.
According to the fourth aspect of the present invention, the inlet of the oil supply passage opens into an oil supply groove that is axially separated from the journal oil passage, so that the inlet for the oil supply passage opens to the journal oil passage. Compared to the lubrication structure, it is possible to prevent the lubricating oil in the journal oil passage for lubricating between the cam holder and the journal section from being excessively discharged into the oil supply passage, thus ensuring the amount of oil in the journal oil passage. Becomes easier. As a result, in the internal combustion engine in which a part of the lubricating oil in the bearing hole in the oil groove is supplied to the contact site, it is possible to ensure good lubricity between the cam holder and the journal portion.
According to the fifth aspect of the present invention, since the lubricating oil in the oil supply passage that guides the lubricating oil in the bearing hole of the cam holder to the contact portion can be smoothly guided from the inlet to the outlet using gravity, the bearing hole It becomes difficult to be affected by the oil pressure fluctuation of the inside lubricating oil, the amount of oil supplied to the contact portion is stabilized, and the lubricity at the contact portion is improved.

FIG. 4 is a view of an essential part when an internal combustion engine provided with a valve-lubricating lubrication structure to which the present invention is applied is viewed from the axial direction, and a part of one bank is centered on the II line in FIG. 3. It is shown in section and part of an internal combustion engine is schematically shown. FIG. 2 is an enlarged view of the vicinity of an intake valve and an intake rocker arm of the internal combustion engine of FIG. 1. It is a figure of the principal part in the III arrow view of FIG. FIG. 2 is a perspective view of an essential part of the internal combustion engine of FIG. 1 when an upper cam holder is removed from the cam holder.

Hereinafter, embodiments of the present invention will be described with reference to FIGS.
Referring to FIG. 1, an internal combustion engine E to which the present invention is applied is a V-type internal combustion engine as a multi-cylinder internal combustion engine provided in a vehicle as a machine.
The internal combustion engine E includes an engine body Ea including a pair of banks (one bank is shown in FIG. 1; hereinafter, simply referred to as “bank”) that forms a V shape when viewed from the axial direction, and the engine A crankshaft 12 rotatably supported on the main body Ea, valve devices 20 and 30 provided on the engine main body Ea and including an intake valve 21 for opening and closing the intake port 7 and an exhaust valve 31 for opening and closing the exhaust port 9; And a valve gear 40 including camshafts 41 and 42 which are rotatably supported by the main body Ea and are driven to rotate by the crankshaft 12 to open and close the intake valve 21 and the exhaust valve 31.
Since both banks have the same structure, the following description will focus on the illustrated bank structure.

  In the specification or claims, the axial direction is assumed to be a direction parallel to the cam center line, which is the rotation center line of the cam shaft, and the vertical direction is the vertical direction. The radial direction is a radial direction centered on the cam center line unless otherwise specified. Furthermore, it is assumed that the vertically upward (or vertically downward) is directly above (directly below) or above (downward) in a direction parallel to the vertical direction. Therefore, the term “upper (lower)” includes not only vertically upward (vertically downward) but also diagonally upward (diagonally downward).

The engine body Ea includes a cylinder block 1 having a plurality of cylinders 1b arranged to form a pair of cylinder portions 1a (FIG. 1 shows a cylinder portion 1a of one bank), In the cylinder block 1, a cylinder head 2 coupled to the upper end portion of each cylinder portion 1a, a head cover 3 coupled to the upper end portion of the cylinder head 2, and an oil pan (illustrated) coupled to the lower end portion of the cylinder block 1 Z)).
The lower part of the cylinder block 1 and the oil pan constitute a crankcase that forms a crank chamber in which the crankshaft 12 of the internal combustion engine E is disposed, and the crankcase has a crank center line Lo that is a rotation center line. The shaft 12 is rotatably supported.

  Each cylinder portion 1a is composed of one or a plurality of cylinders 1b. In this embodiment, both cylinder portions 1a have the same number of cylinders 1b arranged in the axial direction. Each bank includes a cylinder portion 1a, a cylinder head 2, and a head cover 3.

Each cylinder 1b having a cylinder axis Lc that is inclined with respect to the horizontal plane is provided with a piston 4 that fits in a reciprocating manner, and a combustion chamber 5 formed by the cylinder 1b, the cylinder head 2, and the piston 4 is provided for each cylinder 1b. Further, an intake port 7 is provided in the cylinder head 2 for guiding intake air flowing through an intake device 6 connected to the cylinder head 2 on the bank space S side formed between both banks in the horizontal direction to the combustion chamber 5. A pair of an exhaust port 9 for introducing combustion gas from the combustion chamber 5 as exhaust gas to an exhaust device 8 connected to the cylinder head 2 on the opposite side of the bank space S across the cylinder portion 1a and an intake port 7 Each of the intake ports 7a and the exhaust port 9 that opens and closes the pair of exhaust ports 9a respectively faces a pair of intake valves 21 and a pair of exhaust valves 31 as engine valves and the combustion chamber 5. A spark plug 10 is provided for each cylinder 1b. The ignition plug 10 is accommodated in an accommodation cylinder 14 provided in the cylinder head 2 together with an ignition coil connected to the ignition plug 10.
The piston 4 is driven by the pressure of the combustion gas generated by the combustion of the mixture of fuel and intake air supplied from the fuel injection valve and ignited by the ignition plug 10 in the combustion chamber 5, and reciprocates. The crankshaft 12 is driven to rotate through 11.

The valve devices 20, 30 provided for each cylinder 1b corresponding to each cylinder 1b are composed of an intake valve device 20 and an exhaust valve device 30.
The cylinder axis Lc of each cylinder 1b is inclined with respect to the horizontal plane so that the intake valve device 20 or the intake valve 21 is disposed above the exhaust valve device 30 or the exhaust valve 31.

  Since the structures related to the exhaust valve 31 in the exhaust valve device 30 and the valve operating device 40 are basically the same as those structures related to the intake valve 21, in the following description, for the sake of simplicity, the main structure will be described. The structure related to the intake valve 21 will be described below, and the description of the structure related to the exhaust valve 31 will be described in parentheses as necessary when the terms or symbols are different.

  Referring also to FIG. 2, each intake valve device 20 (exhaust valve device 30) has one intake valve 21 (exhaust valve 31) supported by the cylinder head 2 so that the intake port 7a (exhaust port 9a) can be opened and closed. A valve spring 22 (32) consisting of a compression coil spring that urges the intake valve 21 (exhaust valve 31) consisting of a poppet valve in the valve closing direction by a spring force, and a valve stem 21a of the intake valve 21 (exhaust valve 31) ( A pair of upper and lower retainers 23, 24 (33, 34) for holding the valve spring 22 (32) in a state where the upper and lower ends of the valve spring 22 (32) arranged so as to surround 31a) are in contact with each other; A cotter 25 (35) is provided as a fixture for fixing the retainer 23 (33) to the upper end portions 21b and 31b of the valve stem 21a (31a) of the intake valve 21 (exhaust valve 31).

The intake valve 21 (exhaust valve 31) is slidably supported by a cylindrical valve guide 13 fixed to the cylinder head 2 in a valve stem 21a (31a). The retainer 23 for the intake valve 21 and the retainer 33 for the exhaust valve 31 have basically the same structure.
The upper end 21b (31b) of the valve stem 21a (31a), the valve spring 22 (32), the retainers 23, 24 (33, 34), and the cotter 25 (35) together with the valve operating device 40, the cylinder head 2 and the head cover 3 Are arranged in a valve operating chamber 15 formed by

With reference to FIG. 2, the intake valve 21 will be mainly described.
An upper end portion 21b of the valve stem 21a passes through the center of the retainer 23, which is a disc-like member extending in the radial direction about the valve axis Lv, which is the central axis of the intake valve 21, here. A through hole 26 is provided. Furthermore, the upper surface 27 of the retainer 23 has an annular flat surface portion 27a included in the flat surface P1 orthogonal to the valve axis Lv, and a concave portion 27b that is recessed around the through hole 26 with respect to the flat surface portion 27a. The concave portion 27b cooperates with the cotter 25 and the upper end portion 21b to form a concave oil reservoir 28 capable of storing lubricating oil. The plane P1 is an inclined surface that is inclined with respect to the horizontal plane.

  The upper end portion 21 b of the valve stem 21 a slightly protrudes upward from the flat portion 27 a of the upper surface 27 of the retainer 23. Here, the slight amount means that the lubricating oil supplied from an oil supply passage 71 of the lubricating structure 70 described later and flowing down the upper surface 27 can lubricate the upper end surface 21c of the upper end portion 21b. As another example, on the condition that the lubricating oil 70 can supply the lubricating oil to the upper end surface 21c, the upper end portion 21b may not protrude upward from the plane P1 including the plane portion 27a.

  Referring to FIGS. 1, 3, and 4, the valve gear 40 provided in each bank is driven by the power of the crankshaft 12 transmitted via a valve gear transmission mechanism (for example, a transmission mechanism including a timing belt). An intake cam shaft 41 and an exhaust cam shaft 42 as cam shafts to be rotationally driven, an intake cam 43 and an exhaust cam 44 as valve operating cams provided on a pair of cam shafts 41 and 42, and an intake cam 43 and An intake rocker arm 45 and an exhaust rocker arm 46 as cam followers that are driven by the exhaust cam 44 to open and close the intake valve 21 and the exhaust valve 31, respectively, and a pair of rocker shafts 47 that swingably support the rocker arms 45 and 46. , 48.

  The cam shafts 41 and 42 having cam center lines Li and Le parallel to the crank center line Lo are rotatably supported by a plurality of cam holders 50 coupled to the cylinder head 2 by bolts 19. A plurality of cam holders 50 arranged at intervals in the axial direction in the valve operating chamber 15 include two end cam holders 50a positioned at both ends in the axial direction (FIG. 3 and FIG. 4 show one end cam holder). 50a), and an intermediate cam holder 50b positioned between the both end cam holders 50a in the axial direction. Each cam holder 50 rotatably supports journal portions 41a and 42a (see also FIG. 3) of the intake cam shaft 41 and the exhaust cam shaft 42, respectively.

Each cam holder 50 is coupled to the cylinder head 2 and has a lower cam holder 51 as a first cam holder that holds the rocker shafts 47 and 48, and an upper cam holder 52 as a second cam holder that is coupled to the upper end of the lower cam holder 51. Consists of The lower and upper cam holders 51 and 52 are fixed to the cylinder head 2 by bolts 19 that pass through both of them and are screwed into the cylinder head 2. The pair of rocker shafts 47 and 48 are fixed and held by the lower cam holder 51.
All the upper cam holders 52 are integrated by connecting the upper cam holders 52 adjacent in the axial direction by connecting walls 53, and all the upper cam holders 52 and all the connecting walls 53 are one member integrally formed. An upper cam holder body is configured.

Each cam holder 50 includes a lower bearing surface 55a (57a) as a first bearing surface and an upper bearing surface as a second bearing surface that form semi-cylindrical recessed spaces provided in the lower and upper cam holders 51 and 52, respectively. An intake bearing hole 56 (exhaust bearing hole 58) having a bearing surface 55 (57) constituted by 55b (57b) as a peripheral wall surface is provided. A journal portion 41a (42a) of the intake cam shaft 41 (exhaust cam shaft 42) is disposed in the bearing hole 56 (58).
Between the bearing surface 55 (57) and the journal surface 41b (42b) between the bearing surface 55 (57) and the journal surface 41b (42b) which is the outer peripheral surface of the journal portion 41a (42a) in the radial direction. A journal oil passage 65 (66) for supplying lubricating oil is provided. In this embodiment, the journal oil passage 65 (66) is formed by an oil groove 67 (68) provided over the entire circumference of the bearing surface 55 (57) and in the center of the bearing surface 55 (57) in the axial direction. It is formed. The intake camshaft 41, the bearing hole 56 and the oil groove 67 (68) are positioned above the retainer 23 for the intake valve 21, and the exhaust camshaft 42, the bearing hole 58 and the oil groove 67 (68) are the exhaust valve. It is located above the retainer 33 for 31.

  The camshaft 41 (42) has a shaft as a main oil passage through which the lubricating oil pumped from the oil pan and discharged by the oil pump driven by the crankshaft 12 is guided through the cylinder portions 1a and the cylinder head 2. An oil passage 61 (62) is provided. Lubricating oil in the in-shaft oil passage 61 (62) passes through an oil groove 67 (68) or a journal oil passage through a distribution oil passage 63 (64) which is an oil passage extending radially from the oil passage 61 (62). Guided by 65 (66), the sliding portion composed of the bearing surface 55 (57) and the journal surface 41b (42b) is lubricated.

  The intake cam 43 (exhaust cam 44) includes a pair of pause cams 43a (44a) that keep the intake valve 21 (exhaust valve 31) substantially closed without swinging the rocker arm 45 (46), and 1 A pair of low lift cams 43b (44b) and a high lift cam 43c that opens the intake valve 21 (exhaust valve 31) with a high lift amount that is larger than the low lift amount that is the lift amount by the low lift cam 43b (44b). (44c).

An intake rocker arm 45 (exhaust rocker arm 46) disposed between a pair of cam holders 50 adjacent in the axial direction is a pair of drive rocker arms 45a (46a) that respectively contact the pair of intake valves 21 (exhaust valves 31). And a pair of first free rocker arms 45b (46b) and one second free rocker arm 45c (46c). Each drive rocker arm 45a (46a) has a slipper 45a1 (46a1) as a cam abutting portion that can come into contact with the pause cam 43a (44a), and a valve abutting portion that can come into contact with the intake valve 21 (exhaust valve 31). Adjustment screw 45a2 (46a2). Each of the free rocker arms 45b and 45c (46b and 46c) has rollers 45b1 and 45c1 (46b1 and 46c1) as cam contact portions that can contact the cams 43b and 43c (44b and 44c).
An upper end surface 21c as a valve side contact surface in the intake valve 21 and a lower end surface 45a3 as a drive side contact surface in the adjustment screw 45a2 constitute a contact portion Ci between the intake valve 21 and the drive rocker arm 45a. Similarly, the upper end surface of the upper end portion 31b as the valve side contact surface in the exhaust valve 31 and the lower end surface 46a3 as the drive side contact surface of the adjustment screw 46a2 constitute a contact portion Ce of the exhaust valve 31 and the drive rocker arm 46a. To do.

  The rocker arm 45 (46), the cam 43 (44), the drive rocker arm 45a (46a), and the free rocker arm 45b (46b) are arranged to be connected to the drive rocker arm 45a (46a) and the free rocker arm 45b (46b). The drive rocker arm 45a (46a) and the free rocker arm 45c (46c) are arranged across a first connection switching mechanism (not shown) having a pin for switching the state, the drive rocker arm 45a (46a) and the free rocker arm 45c (46c). ) And a second connection switching mechanism (not shown) having a pin for switching the connection state to the connection state, and a hydraulic oil passage 49a (49b) provided in the rocker shaft 47 (48) with respect to the both connection switching mechanisms. The hydraulic control valve that supplies and discharges hydraulic oil is a low valve stop in which the open / close operation of each intake valve 21 (exhaust valve 31) is maintained substantially closed according to the operating state of the internal combustion engine E, and low Lift amount A known lift amount variable mechanism is configured to switch between a valve opening operation and a valve opening operation with a high lift amount.

In each bank, the intake valve 21 is a specific engine valve that is disposed above the exhaust valve 31 and is located at the uppermost position among all the engine valves included in the internal combustion engine E. Therefore, since the intake valve 21 and the contact part Ci are located in the upper part of the valve operating chamber 15, the oil droplet falling in the valve operating chamber 15 cannot sufficiently lubricate the contact part Ci. On the other hand, the contact portion Ce between the exhaust valve 31 and the drive rocker arm 46a is lubricated by the drop of oil in the valve operating chamber 15.
Therefore, the internal combustion engine E is provided with a valve operating lubrication structure 70 that lubricates the contact portion Ci between the intake valve 21 and the drive rocker arm 45a.

1 to 4, the lubrication structure 70 has an inlet 71 i that opens into a bearing hole 56 in which the journal portion 41 a of the intake camshaft 41 is disposed, and lubricates the oil groove 67 in the bearing hole 56. An oil supply path 71 that guides oil vertically above the retainer 23 (that is, a position directly above the retainer 23 or overlaps the retainer 23 in plan view), and a lower bearing that is one of the bearing surfaces of the lower bearing surface 55a and the upper bearing surface 55b An oil supply groove 72 as a lubricating oil supply source provided on the surface 55a (and hence the lower cam holder 51) and having an inlet 71i opened, and a retainer 23 for guiding the lubricant dropped from the outlet 71o of the oil supply passage 71 to the contact site Ci. Is done.
The oil supply groove 72 is provided on the bearing surface 55 of the intake bearing hole 56 as the uppermost bearing hole in each cam holder 50. In addition, in the plurality of cam holders 50 arranged in the axial direction, a pair of oil supply grooves 72 are provided in the intermediate cam holder 50b positioned between the two end cam holders 50a in the axial direction with the oil groove 67 interposed therebetween in the axial direction. It is done.

  The oil supply passage 71 is connected to a holder hole 81 that forms an upstream oil supply passage 71a having an inlet 71i, and a lower cam holder 51 that is one of the lower cam holder 51 and the upper cam holder 52, and is connected to the upstream oil supply passage 71a downstream thereof. This is formed by an oil supply pipe 82 forming a downstream oil supply passage 71b that communicates at the end. The oil supply pipe 82 is a pipe having a closed cross section. Accordingly, the oil supply passage 71 is an oil passage formed by a passage wall having a closed cross section from the inlet 71i to the outlet 71o.

The holder hole 81 is composed of two substantially straight holes provided in the lower cam holder 51. The oil supply pipe 82 includes a substantially straight straight pipe part 82a having a base part 82a1 as an upstream end connected to the lower cam holder 51, and a downstream of the oil supply pipe 82 bent downward from the straight pipe part 82a, preferably vertically downward. And a bent tube portion 82b which is an end portion.
The oil supply passage 71 includes a straight oil passage 71c extending substantially straight in the cam holder 50, a straight oil passage 71d extending substantially straight in each of the cam holder 50 and the straight pipe portion 82a, and a straight oil passage 71d. And a bent oil passage 71e which is bent vertically downward and has a lower end serving as an outlet 71o. As another example, in the oil supply passage 71, the oil passage portion from the inlet 71i to the bent pipe portion 82b may be a substantially straight passage, which makes it easier for the lubricating oil to flow through the oil supply passage 71. .
Here, the expression “almost” includes the case where there is no modifier “almost” and is not exactly the same as the case where there is no modifier “almost”, but the modification “almost”. It means a range where there is no significant difference in terms of action and effect compared to the case where there is no word.

  The base portion 82a1 is inserted into a protruding portion 51e that protrudes obliquely downward in a direction approaching each other in the axial direction from the side surfaces 51c and 51d facing each other in the axial direction of the lower cam holder 51 adjacent in the axial direction. Further, the lower end of the bent pipe portion 82b forms an outlet 71o that opens vertically downward.

The oil supply path 71 extends from the inlet 71i to the outlet 71o below the uppermost portion of the bearing hole 56 provided with the oil groove 67, in this embodiment, the uppermost portion of the sliding surface with the journal portion 41a in the bearing surface 55. It is located below. Lubricating oil in the oil supply passage 71 flows without flowing upward until it reaches the outlet 71o from the inlet 71i, and in this embodiment, it always flows downward until it reaches the outlet 71o. Can be effectively utilized to guide the lubricating oil in the oil supply groove 72 to the outlet 71o.
Here, the bearing hole 56 also includes an oil groove 67 provided in the bearing surface 55.
As another example, the oil supply passage 71 may have a locally horizontal portion.

The contact portion Ci and the outlet 71o are at a position intersecting with the plane P2 orthogonal to the cam center line Li of the cam shaft 41 (see FIG. 3), and the outlet 71o is in the inclination direction A of the retainer 23 or the plane portion 27a in plan view. In FIG. 2, it is located closer to the upward inclination direction A1 than the contact part Ci (see FIG. 2). Here, the inclination direction A is a direction on the orthogonal plane P2 or on a plane parallel to the orthogonal plane P2.
In addition, as shown by a two-dot chain line in FIG. 2, the outlet 71o is in contact in a plan view when the intake valve 21 is lifted (in FIG. 2, the lifted state at the high lift cam 43c is shown). It is arranged so as to be closer to the contact part Ci than the position of the drop when the intake valve 21 is closed, closer to the upward inclination direction A1 than the part Ci. For this reason, when the intake valve 21 is lifted, it falls to the upper surface 27 at a position closer to the contact site Ci, so that the dropped lubricating oil is more easily supplied to the contact site Ci.

  The oil supply groove 72 is provided on the bearing surface 55a adjacent to the oil groove 67 in the axial direction. Since the inlet 71i opens into the oil supply groove 72, the amount of oil flowing into the oil supply path 71 from the lubricating oil in the oil groove 67 is suppressed as compared with the case where the inlet 71i of the oil supply path 71 opens into the oil groove 67. Thus, an appropriate amount of lubricating oil can be supplied to the contact portion Ci through the oil supply passage 71 while ensuring good lubrication between the bearing surface 55 and the journal surface 41b.

  During operation of the internal combustion engine E, the lubricating oil discharged from the oil pump flows into the oil groove 67 (68) through the in-shaft oil passage 61 (62) and the distribution oil passage 63 (64), and the oil groove 67 (68) The bearing surface 55 (57) and the journal surface 41b (42b) are lubricated by the lubricating oil. A part of the lubricating oil in the oil groove 67 of the bearing surface 55 that supports the intake camshaft 41 flows into the oil supply groove 72, and another part flows out between the bearing surface 55 and the journal surface 41b into the valve operating chamber 15. To do. The lubricating oil in the oil supply groove 72 flows into the oil supply passage 71 from the inlet 71i, and falls or drops on the upper surface 27 of the retainer 23 from the outlet 71o. The lubricating oil falling on the upper surface 27 flows down on the upper surface 27 toward the contact site Ci and the oil reservoir 28, and a part thereof is supplied to the contact site Ci to lubricate the contact site Ci. Further, the lubricating oil collected in the oil reservoir 28 lubricates the upper end portion 21b, the cotter 25 and the retainer 23, and the lubricating oil is retained in the oil reservoir 28, so that the outlet of the oil supply passage 71 continues. Lubricating oil that falls from 71o to the upper surface 27 and flows down toward the contact portion Ci is easily supplied to the contact portion Ci.

Next, operations and effects of the embodiment configured as described above will be described.
The internal combustion engine E including the valve operating device 40 is provided with a valve operating lubrication structure 70 that lubricates a contact portion Ci where the intake valve 21 and the drive rocker arm 45a are in contact with each other. The lubrication structure 70 has an inlet 71i that opens into the bearing hole 56 of the cam holder 50 in which the journal portion 41a of the intake camshaft 41 is disposed, and the lubricating oil in the bearing hole 56 is vertically above the upper surface 27 of the retainer 23. The oil supply path 71 is composed of a retainer 23 that guides lubricating oil dropped from the outlet 71o of the oil supply path 71 to the contact portion Ci. The oil supply path 71 extends from the inlet 71i to the outlet 71o at the top of the bearing hole 56. It is located below. With this structure, the oil supply passage 71 that guides the lubricating oil in the bearing hole 56 of the cam holder 50 to the contact site Ci passes the lubricating oil above the top of the bearing hole 56 (58) from the inlet 71i to the outlet 71o. Since there is no need to guide the lubricating oil in the bearing hole 56 to the outlet 71o using gravity, the lubricating oil in the bearing hole 56 can be guided to the upper surface of the cam holder 50 as compared with the valve train lubricating structure. As a result, the amount of the lubricating oil supplied to the contact portion Ci is less affected by the hydraulic pressure fluctuation of the lubricating oil in the bearing hole 56. As a result, in the lubrication structure 70, the amount of oil supplied to the contact site Ci is stabilized, so that the required oil amount can be secured stably and the lubricity at the contact site Ci is improved.

  The lubricating oil in the oil supply passage 71 flows through the oil supply passage 71 without reaching the outlet 71o from the inlet 71i, thereby guiding the lubricating oil in the bearing hole 56 of the cam holder 50 to the contact portion Ci. Since the lubricating oil in 71 can be smoothly guided from the inlet 71i to the outlet 71o using gravity, the lubricating oil in the bearing hole 56 is less affected by the oil pressure fluctuation and supplied to the contact portion Ci. This stabilizes the amount of oil and improves the lubricity at the contact site Ci.

  The oil supply passage 71 is formed by a holder hole 81 provided in the lower cam holder 51 of the cam holder 50 and an oil supply pipe 82 connected to the cam holder 50 so as to communicate with the holder hole 81. The oil supply pipe 82 has an outlet 71o. By having the bent pipe portion 82b bent vertically downward so as to open vertically downward, the oil supply passage 71 becomes an oil passage having a closed cross section from the inlet 71i to the outlet 71o. Compared to the case where the oil passage is formed by a groove and has an open cross section, the lubricating oil in the oil supply passage 71 reaches the outlet 71o due to vibrations of the internal combustion engine E, vibrations caused by running of the vehicle, running conditions, and the like. Jumping out from the oil supply passage 71 in the meantime is prevented. In addition, the lubricating oil in the oil supply passage 71 can be concentrated on the upper surface 27 of the retainer 23 by the bent pipe portion 82b bent downward vertically and the outlet 71o opening downward vertically, so that it can be efficiently dropped. it can. As a result, since the amount of oil supplied to the contact site Ci is stabilized, the lubricity at the contact site Ci is improved.

  The upper surface 27 of the retainer 23 is inclined with respect to the horizontal plane, the contact portion Ci and the outlet 71o are at a position intersecting the plane P2 orthogonal to the cam center line Li of the cam shaft 41, and the outlet 71o is in plan view. By being positioned closer to the upward inclination direction A1 than the contact part Ci in the inclination direction A, the lubricating oil that has dropped from the oil supply passage 71 to the upper surface 27 of the retainer 23 is directed downward on the upper surface 27 toward the contact part Ci. Flow down to A2. As a result, the amount of lubricating oil flowing down the upper surface 27 and supplied to the contact site Ci is stabilized, so that the lubricity at the contact site Ci is improved.

  A journal oil passage 65 is provided between the bearing surface 55 of the bearing hole 56 and the journal surface 41b of the journal portion 41a that is in sliding contact with the bearing surface 55, and the inlet 71i is a journal oil passage in the axial direction of the cam shaft 41. An oil supply groove 72 provided on the bearing surface 55 adjacent to the passage 65 (or the oil groove 67) opens, so that the inlet 71i of the oil supply passage 71 is separated from the journal oil passage 65 in the axial direction. Since it opens in the groove 72, the journal oil passage 65 for lubricating between the cam holder 50 and the journal portion 41a as compared with the valve operating lubrication structure in which the inlet 71i of the oil supply passage 71 opens in the journal oil passage 65 is provided. Since the lubricating oil inside can be prevented from flowing out excessively into the oil supply passage 71, it is easy to secure the amount of oil in the journal oil passage 65. As a result, in the internal combustion engine E in which a part of the lubricating oil in the bearing hole 56 in the journal oil passage 65 is supplied to the contact site Ci, good lubricity is ensured between the cam holder 50 and the journal portion 41a. it can.

  The oil supply pipe 82 extends between the cam holders 50 adjacent in the axial direction, and extends from the side surfaces 51c and 51d in the axial direction toward the retainer 23 in the cam holder 50 in the axial direction and obliquely downward. Therefore, the oil supply pipe 82 and thus the lubricating structure 70 can be arranged in a compact manner by utilizing the space formed between the cam holders 50 adjacent in the axial direction.

Hereinafter, an embodiment in which a part of the configuration of the above-described embodiment is changed will be described with respect to the changed configuration.
The journal oil passage 65 (66) may be formed by an oil groove provided in at least one of the bearing surface 55 (57) and the journal surface 41b (42b).
The inlet 71 i of the oil supply passage 71 may open to the bearing surface 55.
In the valve device, the cylinder axis of the cylinder may be inclined so that each exhaust valve device is disposed above the intake valve device. In that case, the lubrication structure 70 is provided for the exhaust valve device. It is done.
The cam holder may be composed of a single member without being divided into the lower cam holder 51 and the upper cam holder 52. The upper cam holder may be divided for intake and exhaust.
The valve gear 40 may include a common camshaft that drives the intake valve and the exhaust valve.
The cylinder may have a cylinder axis parallel to the vertical direction. In this case, the valve axis of the engine valve is inclined with respect to the horizontal plane, so that a lubrication structure for valve actuation can be applied.
The internal combustion engine may be a single cylinder internal combustion engine or a series internal combustion engine in which a plurality of cylinders 1b are arranged in a line. The internal combustion engine may be provided in a machine other than the vehicle, for example, a generator driven by the internal combustion engine.

2 ... Cylinder head, 15 ... Valve operating chamber, 20 ... Intake valve device, 21 ... Intake valve, 23, 24 ... Retainer, 27 ... Upper surface, 40 ... Valve drive device, 41, 42 ... Cam shaft, 41b, 42b ... Journal Surface, 43 ... intake cam, 44 ... exhaust cam, 45, 46 ... rocker arm, 50 ... cam holder, 55, 57 ... bearing surface, 56, 58 ... bearing hole, 67, 68 ... oil groove, 70 ... lubrication structure, 71 ... Refueling path, 71i ... inlet, 71o ... outlet, 72 ... oil supply groove, 81 ... holder hole, 82 ... oil supply pipe,
E ... Internal combustion engine, Ci ... Contact part, A ... Inclination direction.

Claims (5)

A valve device comprising an engine valve and a retainer that holds a valve spring that biases the engine valve in a valve closing direction;
An internal combustion engine comprising: a camshaft rotatably supported by a cam holder; and a valve operating device that is driven by a valve operating cam of the camshaft to open and close the engine valve.
A valve operating lubrication structure for lubricating a contact portion where the engine valve and the cam follower are in contact with each other;
The lubrication structure has an inlet that opens into a bearing hole of the cam holder in which the journal portion of the cam shaft is disposed, and feeds the lubricating oil in the bearing hole vertically above the upper surface of the retainer; The retainer that guides the lubricating oil dropped from the outlet of the oil supply passage to the contact portion,
The internal combustion engine, wherein the oil supply passage is located below the uppermost portion of the bearing hole from the inlet to the outlet. The internal combustion engine of claim 1,
The oil supply path is formed by a holder hole provided in the cam holder and an oil supply pipe connected to the cam holder so as to communicate with the holder hole,
The internal combustion engine, wherein the oil supply pipe has a bent pipe portion bent downward in the vertical direction so that the outlet opens downward in the vertical direction. The internal combustion engine according to claim 1 or 2,
The upper surface is inclined with respect to a horizontal plane;
The contact portion and the outlet are at a position that intersects a plane perpendicular to the cam center line of the cam shaft,
The internal combustion engine according to claim 1, wherein the outlet is positioned closer to the tilt direction upward than the contact portion in the tilt direction in plan view. The internal combustion engine according to any one of claims 1 to 3,
A journal oil passage is provided between the bearing surface of the bearing hole and the journal surface of the journal portion in sliding contact with the bearing surface,
The internal combustion engine, wherein the inlet opens in the oil supply groove provided on the bearing surface or the journal surface adjacent to the journal oil passage in the axial direction of the cam shaft. The internal combustion engine according to any one of claims 1 to 4,
The internal combustion engine, wherein the lubricating oil in the oil supply passage flows through the oil supply passage without going upward from the inlet to the outlet.

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