JP3603357B2 - Valve train lubrication system for internal combustion engine - Google Patents

Description

[0001]
[Industrial applications]
The present invention relates to a lubricating device for a valve train for opening and closing an intake valve or an exhaust valve of an internal combustion engine (hereinafter, both of them are collectively referred to as intake and exhaust valves), in particular, a contact portion between a rocker arm tip and an intake and exhaust valve. And a lubricating device for lubricating both a cam follower of the rocker arm and a sliding portion of the cam.
[0002]
[Prior art]
A valve mechanism of an internal combustion engine generally transmits a cam lift to an intake valve or an exhaust valve via a rocker arm that can swing, and pushes open the intake valve and the exhaust valve that are biased in a closing direction by a valve spring. However, when the valve is lifted, a large surface pressure acts on both the contact part between the rocker arm tip and the intake and exhaust valves and the sliding part between the cam follower and the cam. Requires lubrication.
[0003]
For example, in Japanese Utility Model Laid-Open Publication No. 61-160210, a lubricating oil supply pipe is provided above a camshaft in parallel with the camshaft, and lubricating oil is supplied to the lubricating oil supply pipe for each of a plurality of cams. A configuration is shown in which a supply hole is formed as an opening and lubricating oil is jetted toward each cam. In this device, lubrication is not taken into consideration for the contact portion between the tip of the rocker arm and the intake / exhaust valve. For example, the lubrication is performed by oil mist existing in the space inside the rocker cover.
[0004]
In Japanese Utility Model Laid-Open Publication No. 63-183407, a lubricating oil supply hole is formed in each of a rocker arm tip and a cam, and a contact portion between the rocker arm tip and an intake / exhaust valve, and a cam and a cam follower are formed. The configuration shown is such that lubricating oil is supplied to each of the sliding contact portions.
[0005]
[Problems to be solved by the invention]
However, the lubrication of the contact portion between the rocker arm tip and the intake / exhaust valve depends on the oil mist as in the former case, but there is a possibility that lubrication may not be sufficient, for example, at high engine speeds. There is.
[0006]
In addition, in the configuration in which lubricating oil supply holes are separately provided for the tip of the rocker arm and the cam as in the latter case, a plurality of lubricating oil supply holes are required for one rocker arm, and the number of processing steps is reduced. In addition to the increase, the supply amount of lubricating oil required for lubrication of the valve train becomes extremely large, and there is a problem that the oil pump needs to be enlarged.
[0007]
Also, in any configuration, since the lubricating oil is continuously supplied to one lubricating portion, the lubricating oil is continuously supplied even at a low surface pressure time when a large amount of the lubricating oil is not necessarily required, There is much waste of lubricating oil supply.
[0008]
[Means for Solving the Problems]
Therefore, the present invention provides an internal combustion engine having a rocker arm whose base end is swingably supported and whose front end presses a valve stem end of an intake / exhaust valve, and a cam follower on the back surface slides on the cam. In the valve operating system, a lubricating oil supply pipe is provided above the cam, and a lubricating oil supply hole formed in the lubricating oil supply pipe is formed so that the lubricating oil is ejected as an oil jet. The linear trajectory of the lubricating oil directed toward the rocker arm tip toward the rocker arm tip contacting the valve and flowing as an oil jet from the lubricating oil supply hole to the rocker arm tip is the base circle of the cam. without crossing the part, so that cam nose portion, traverses along with the rotation, as characterized by setting the positional relation of each portion That.
[0009]
According to a second aspect of the present invention, there is provided a camshaft in which first and second cams having different profiles are formed side by side, a base end portion swingably supported and a tip end portion of a valve stem end portion of an intake / exhaust valve. And a main rocker arm whose back cam follower is in sliding contact with the first cam; a sub rocker arm that is swingably supported adjacent to the main rocker arm and driven by the second cam; A connection mechanism for selectively connecting or disconnecting the rocker arm to the rocker arm, a lubricating oil supply pipe is provided above the camshaft, and the lubricating oil is ejected as an oil jet. in the lubricating oil supply pipe to the opening formed in the lubricating oil supply hole, so that the oil jet is directed to the main rocker arm tip in contact with the intake and exhaust valves as With directing the main rocker arm tip, linear trajectory of the lubricating oil toward the oil jet from the lubricating oil supply hole to the main rocker arm tip, without intersecting the base circle portion of the first cam, It is characterized in that the positional relationship of each part is set such that the cam nose part crosses with its rotation.
[0010]
In the invention according to claim 3, the tip of the rocker arm or the tip of the main rocker arm to which the lubricating oil supply hole is directed is formed in a cross-sectional shape that is convex toward the lubricating oil supply hole.
[0011]
[Action]
The lubricating oil pressurized by the oil pump of the internal combustion engine and guided to the lubricating oil supply pipe is jetted from the lubricating oil supply hole. Since the lubricating oil supply hole is directed toward the tip of the rocker arm, the lubricating oil tries to move toward the tip of the rocker arm. Here, as the cam rotates, the cam nose portion intermittently crosses the trajectory of the lubricating oil. Therefore, when the cam nose crosses the lubricating oil trajectory, the lubricating oil collides with the cam nose and adheres to the cam nose. The lubricating oil attached to the cam nose lubricates between the cam nose and the cam follower during valve lift. Further, when the cam surface close to the lubricating oil locus becomes a base circle portion other than the cam nose portion, the lubricating oil locus does not intersect the cam. Therefore, the lubricating oil ejected from the lubricating oil supply hole goes to the tip of the rocker arm without being blocked by the cam, and lubricates the contact portion between the tip of the rocker arm and the intake / exhaust valve.
[0012]
That is, the cam nose portion intermittently crosses the flow of the lubricating oil continuously ejected from the lubricating oil supply hole, and the lubricating oil is distributed to both the cam nose portion and the rocker arm tip.
[0013]
According to the second aspect of the present invention, in the variable valve mechanism including the main rocker arm and the sub rocker arm, the above-described lubricating action is performed on the main rocker arm that presses the intake and exhaust valves.
[0014]
Furthermore, in the third aspect, the lubricating oil sprayed from the lubricating oil supply hole onto the tip of the rocker arm or the tip of the main rocker arm flows downward along the surface of the tip having a convex shape, and contacts the intake / exhaust valve. It is quickly supplied to the contact.
[0015]
【Example】
Hereinafter, an embodiment of the present invention will be described in detail with reference to the drawings.
[0016]
FIGS. 1 to 10 show an embodiment in which the present invention is applied to an internal combustion engine having a cam switching type variable valve mechanism. As shown in FIGS. An intake valve 1 for opening and closing a port 4 and an exhaust valve 2 for opening and closing an exhaust port 5 are provided. In this embodiment, a pair of intake valves 1 and a pair of exhaust valves 2 are provided for each cylinder, and one variable valve mechanism including the main and auxiliary rocker arms 6 and 7 is provided with a pair of intake valves 1 or exhaust valves. 2 are simultaneously driven.
[0017]
First, the variable valve mechanism including the main and sub rocker arms 6 and 7 will be described. As shown in FIGS. 3 and 4, the main rocker arm 6 has a substantially Y-shape with the distal end branched in a forked shape. A substantially cylindrical rocker shaft fitting portion 8 at the end is swingably fitted to the rocker shaft 9. A first cam follower 10 made of a hard metal is fixed to the back surface of the bifurcated portion. The bifurcated distal end portions 6a of the main rocker arm 6 are bent downward as shown in FIGS. 4 and 2, respectively, and the valve stem ends of the intake valve 1 (or the exhaust valve 2). Abutting on the part via a shim 11. As shown in FIGS. 9 and 10, the respective rocker shafts 9 on the intake side and the exhaust side are respectively arranged on the outer side of the cylinder head 3, and the tip portions 6a for pressing the intake valve 1 and the exhaust valve 2 are respectively provided on the cylinders. It is located closer to the inside of the head 3.
[0018]
The central portion of the main rocker arm 6 sandwiched between the pair of first cam followers 10 is recessed downward, and the sub rocker arm 7 is provided here. That is, the auxiliary rocker arm 7 is disposed between the pair of first cam followers 10. The sub rocker arm 7 is swingably supported by a sub rocker shaft 12 provided on the upper surface of the base end of the main rocker arm 6. The auxiliary rocker arm 7 is formed to be shorter than the main rocker arm 6, and a second cam follower 13 made of hard metal is provided on the back surface of the distal end. As shown in FIG. 3, the second cam follower 13 is located at a position aligned with the first cam follower 10. The sub-rocker arm 7 does not directly contact the intake valve 1 and the exhaust valve 2.
[0019]
A camshaft 14 arranged above the rocker shaft 9 has a low-speed cam 15 with a small valve lift that slides on the first cam follower 10 of the main rocker arm 6 and a valve lift that slides on the second cam follower 13 of the sub rocker arm 7. A large amount of high-speed cam 16 is formed side by side. The low-speed cams 15 are provided in a pair corresponding to the pair of first cam followers 10, and the high-speed cam 16 is disposed between the pair of low-speed cams 15. The camshaft 14 is rotatably supported by the cylinder head 3 via a cam bracket 17 as shown in FIG.
[0020]
As shown in FIG. 5, the auxiliary rocker arm 7 is rotationally urged upward by a lost motion spring 19 pressed against the upper surface of the concave portion of the main rocker arm 6 via a retainer 18, and is in a state of being separated from the main rocker arm 6. However, the sliding contact with the high-speed cam 16 is maintained.
[0021]
A connecting lever 20 is provided below the auxiliary rocker arm 7 as a connecting mechanism for selectively connecting the main and auxiliary rocker arms 6 and 7. The connecting lever 20 is rotatably supported by a pin 21 provided at the bottom of the main rocker arm 6, and an upper end 20 a thereof can be engaged with an engaging step 22 on the lower surface of the sub rocker arm 7 (FIG. 5, see FIG. 7). The connection lever 20 is constantly urged in the disengagement direction by a return spring 24 that presses the projection 20c (see FIG. 2) via a retainer 23, and faces the lower end 20b. A hydraulic plunger 25 is arranged, and when the plunger 25 projects, it turns in the engaging direction (see FIG. 7). The hydraulic cylinder 26 to which the plunger 25 is slidably fitted is supplied with hydraulic pressure from a hydraulic supply passage 29 in the rocker shaft 9 via an oil hole 27 in the main rocker arm 6 and an oil hole 28 in the rocker shaft 9. It is possible.
[0022]
Therefore, in the above configuration, when a predetermined hydraulic pressure is supplied to the hydraulic cylinder 26 through the hydraulic supply passage 29, the connecting lever 20 rotates in the engaging direction as shown in FIG. I do. Thus, when the auxiliary rocker arm 7 is pressed downward by the high-speed cam 16, the main rocker arm 6 operates integrally, and the intake valve 1 or the exhaust valve 2 opens and closes along the profile of the high-speed cam 16. I will do it. When the hydraulic pressure is released, the connection lever 20 is rotated in the disengagement direction by the return spring 24 as shown in FIG. 5, and the upper end 20 a is separated from the engagement step 22. Therefore, the sub rocker arm 7 is separated from the main rocker arm 6, and the intake valve 1 and the like open and close along the profile of the low-speed cam 15 via the main rocker arm 6.
[0023]
It should be noted that a known sliding connection pin can be used as a connection mechanism instead of the connection lever 20 described above.
[0024]
Next, as a lubricating device for the above-described variable valve mechanism, as shown in FIG. 1, a lubricating oil supply pipe 31 made of a metal pipe is disposed further above the camshaft 14. The lubricating oil supply pipe 31 is continuous from the front end cylinder to the rear end cylinder of the internal combustion engine, and is arranged in parallel with the camshaft 14 and the rocker shaft 9. A plurality of brackets 32 are welded to the lubricating oil supply pipe 31, and the brackets 32 are fastened together by bolts 33 for fixing the cam bracket 17. As shown in FIGS. 9 and 10, the lubricating oil supply pipes 31 are provided on both the intake side and the exhaust side, respectively, and are configured as one continuous U-shaped body as a whole. Alternatively, a pair of lubricating oil supply pipes 31 may be provided in parallel.
[0025]
The lubricating oil supply passage 31a formed in the lubricating oil supply pipe 31 communicates with an oil gallery (not shown) inside the cylinder head 3, and lubricating oil pressurized by an oil pump (not shown) is provided. It is being led.
[0026]
Here, the lubricating oil supply pipe 31 is located substantially on an extension of the center line of the intake valve 1 or the exhaust valve 2 as shown in FIG. As shown in FIG. 2, three lubricating oil supply holes 34 and 35 are formed on the lower surface side of the lubricating oil supply pipe 31 for one variable valve mechanism of each cylinder. More specifically, a pair of lubricating oil supply holes 34 are formed above the pair of low-speed cams 15, and one lubricating oil supply hole 35 is formed in the center corresponding to the high-speed cam 16. . The lubricating oil supply hole 35 corresponding to the central high-speed cam 16 is formed toward the high-speed cam 16, for example, in such a manner as to direct the center axis of the camshaft 14. On the other hand, the pair of lubricating oil supply holes 34 provided at positions corresponding to the low-speed cams 15 do not directly go to the camshaft 14 side but contact the shims 11 of the intake and exhaust valves 1 and 2. The main rocker arm 6 is formed so as to be directed to the tip 6a of the main rocker arm 6 which is in contact therewith.
[0027]
The trajectory L of the lubricating oil obtained along the direction in which the lubricating oil supply hole 34 is formed, ie, the trajectory L of the lubricating oil from the lubricating oil supply hole 34 to the tip 6 a of the main rocker arm 6, , While maintaining a distance within the range of the cam lift amount. That is, the lubricating oil trajectory L from the lubricating oil supply hole 34 does not intersect with the base circle portion 15b of the low-speed cam 15, and the cam nose 15a crosses the lubricating oil trajectory L with respect to the cam nose 15a. The positional relationship of each part is set so that it can be performed.
[0028]
Next, the lubricating action of the above embodiment will be described.
[0029]
As described above, appropriate lubricating oil is introduced into the lubricating oil supply passage 31a in the lubricating oil supply pipe 31, and the lubricating oil is ejected from the lubricating oil supply holes 34 and 35 as oil jets. I do. Lubricating oil is constantly jetted from the central lubricating oil supply hole 35 toward the high-speed cam 16, whereby the sliding contact portion between the high-speed cam 16 and the second cam follower 13 is lubricated well.
[0030]
On the other hand, the lubricating oil is ejected from the lubricating oil supply hole 34 corresponding to the low-speed cam 15 toward the tip 6a of the main rocker arm 6. Then, as shown in FIG. 9, when the base circle portion 15 b of the low-speed cam 15 is approaching the lubricating oil trajectory L, the flow of the lubricating oil ejected from the lubricating oil supply hole 34 is impeded by the low-speed cam 15. To the leading end 6a of the main rocker arm 6 without being moved. Therefore, the space between the tip portion 6a and the shim 11 is reliably lubricated. Since the lubricating oil trajectory L is substantially along the axis of the intake valve 1 and the exhaust valve 2, the lubricating oil surely collides with the tip 6a of the main rocker arm 6 even during the valve lift. Here, the surface pressure at the contact portion between the distal end portion 6a and the shim 11 becomes highest during the valve lift, but the cam nose portion 15a of the low-speed cam 15 is moved by the first cam follower of the main rocker arm 6. Since the lubricating oil trajectory L does not interfere with the cam nose portion 15a in a state where the lubricating oil 10 is depressed, the lubricating oil path L does not interfere with the cam nose portion 15a. Lubricating oil can be supplied reliably.
[0031]
When the low-speed cam 15 rotates and the cam nose portion 15a faces the center of the cylinder head 3 as shown in FIG. 10, the cam nose portion 15a crosses the lubricating oil path L from the lubricating oil supply hole 34. Therefore, the lubricating oil ejected from the lubricating oil supply hole 34 collides with the cam nose portion 15a of the low-speed cam 15 and adheres thereto. The sliding contact portion between the cam nose portion 15a and the first cam follower 10 is lubricated by the attached lubricating oil. The supply of the lubricating oil to the cam nose portion 15a is performed intermittently. However, since lubricating oil is newly supplied to the cam nose portion 15a every one rotation of the camshaft 14, sufficient lubrication can be achieved. it can. In addition, the base circle portion 15b other than the cam nose portion 15a is mainly lubricated by oil mist, but when the base circle portion 15b is in contact with the first cam follower 10, the surface pressure of both is reduced. Since it is approximately 0, there is no problem in lubrication performance.
[0032]
As described above, according to the above-described embodiment, the lubricating oil continuously ejected from the lubricating oil supply hole 34 is alternately distributed and used for the lubrication of the tip 6a of the main rocker arm 6 and the lubrication of the cam nose 15a. And both can be reliably lubricated. In particular, since lubrication is mainly performed for the period where the surface pressure is high and for the portion where the surface pressure is high for each part, reliable lubrication can be performed on both sides while minimizing the lubricating oil supply amount.
[0033]
The lubricating oil colliding with the tip 6a of the main rocker arm 6 flows along the wall around the tip 6a and flows into the shim 11. As in the embodiment shown in FIG. 8, if the tip 6 a of the main rocker arm 6 is formed to have a cross-sectional shape that is convex toward the lubricating oil supply hole 34, the lubricating oil that has collided with the shim 11 It can be more smoothly introduced in between.
[0034]
As described above, an embodiment in which the present invention is applied to a cam switching type variable valve mechanism has been described. However, the present invention is not limited to this, and can be widely applied to a valve operating system using a rocker arm.
[0035]
【The invention's effect】
As is apparent from the above description, according to the valve train lubrication system for an internal combustion engine according to the present invention, one lubricating oil supply hole is used to both the cam and the cam follower and the rocker arm tip and the intake and exhaust valves. Can be efficiently lubricated. Therefore, the number of lubricating oil supply holes provided in the entire lubricating oil supply pipe can be reduced, and both forced lubrication can be achieved with a minimum lubricating oil supply amount without increasing the oil pump capacity. In particular, since the lubricating oil is distributed in consideration of the period and the portion where the surface pressure actually increases, the lubricating oil supply amount can be effectively reduced.
[0036]
Further, when a variable valve mechanism as in claim 2 is used, the number of cams requiring lubrication becomes very large, so that a large number of lubricating oil supply holes are required, and a decrease in hydraulic pressure is likely to occur. Similarly, by distributing the lubricating oil to both the leading end of the main rocker arm and the first cam, reliable lubrication is possible without lowering the oil pressure.
[0037]
According to the third aspect of the present invention, the lubricating oil can be smoothly guided to the contact portion between the rocker arm or the tip of the main rocker arm and the intake / exhaust valve.
[Brief description of the drawings]
FIG. 1 is a sectional view of a main part of a cylinder head showing an embodiment of a lubrication device according to the present invention.
FIG. 2 is a side view of a main part showing a positional relationship between a valve operating mechanism and a lubricating oil supply hole in the embodiment.
FIG. 3 is a plan view showing only a valve operating mechanism.
FIG. 4 is a perspective view showing only a main rocker arm.
FIG. 5 is a sectional view taken along the line AA of FIG. 3;
FIG. 6 is a sectional view taken along the line BB of FIG. 3;
FIG. 7 is a sectional view similar to FIG. 5, showing an engagement state of a connecting lever;
FIG. 8 is a perspective view of a main part showing a different embodiment of the tip of the main rocker arm.
FIG. 9 is a cross-sectional view showing a state in which lubricating oil is being supplied to the tip of the main rocker arm.
FIG. 10 is a sectional view showing a state in which lubricating oil is being supplied to a cam nose portion of a low-speed cam.
[Explanation of symbols]
DESCRIPTION OF SYMBOLS 1 ... Intake valve 6 ... Main rocker arm 7 ... Sub rocker arm 10 ... 1st cam follower 11 ... Shim 14 ... Cam shaft 15 ... Low speed cam 15a ... Cam nose part 16 ... High speed cam 20 ... Connection lever 31 ... Lubricating oil supply pipe 34 ... Lubricating oil supply hole 35 ... Lubricating oil supply hole

Claims (3)

In a valve train of an internal combustion engine, a base end portion is swingably supported, and a front end portion presses a valve stem end portion of an intake / exhaust valve, and a rocker arm in which a rear cam follower is in sliding contact with a cam. A lubricating oil supply pipe is provided above the cam, and a lubricating oil supply hole formed in the lubricating oil supply pipe is formed so that the lubricating oil is ejected as an oil jet. with directing to said rocker arm tip to be directed to the distal end, linear trajectory of the lubricating oil toward the oil jet from the lubricating oil supply hole to the rocker arm tip, not intersect the base circle portion of the cam , the nose portion is, across along with the rotation of the internal combustion engine, characterized in that setting the positional relationship between each part valve system lubrication Location. A camshaft in which first and second cams having different profiles are arranged side by side; a base end portion swingably supported and a front end portion pressing a valve stem end portion of an intake / exhaust valve, and a cam follower on a back surface. A main rocker arm slidingly contacting the first cam, a sub rocker arm swingably supported adjacent to the main rocker arm and driven by the second cam, and selectively connecting the sub rocker arm and the main rocker arm. Or a connection mechanism for disengaging the lubricating oil supply pipe, wherein a lubricating oil supply pipe is provided above the camshaft and the lubricating oil is ejected as an oil jet. an opening formed lubricating oil supply hole, the main rocker arm tip as the oil jet is directed to the main rocker arm tip in contact with the intake and exhaust valves With directing the linear trajectory of the lubricating oil toward the oil jet from the lubricating oil supply hole to the main rocker arm tip, without intersecting the base circle portion of the first cam, the cam nose portion, that A valve train lubrication system for an internal combustion engine, wherein a positional relationship of each part is set so as to cross with rotation. 3. The internal combustion engine according to claim 1, wherein a tip portion of the rocker arm or a tip portion of the main rocker arm to which the lubricating oil supply hole is directed is formed in a cross-sectional shape protruding toward the lubricating oil supply hole. Valve train lubrication system.

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