JP4153806B2 - Variable valve operating device for internal combustion engine - Google Patents

Description

[0001]
BACKGROUND OF THE INVENTION
The present invention relates to a variable valve operating apparatus for an internal combustion engine capable of changing a valve lift characteristic of an intake / exhaust valve (at least one of an intake valve and an exhaust valve), and more particularly to improvement of its lubricity.
[0002]
[Prior art]
In a general gasoline engine, the intake air amount is controlled by controlling the opening degree of a throttle valve provided in the intake passage. In this case, however, the pumping loss particularly in a low load region where the opening degree of the throttle valve is small. There is a problem that is large. Therefore, attempts have been made to control the intake air amount without depending on the throttle valve by changing the intake / exhaust valve opening / closing timing (particularly the intake valve closing timing) and the lift amount with a variable valve device. ing.
[0003]
Patent Document 1 discloses a variable valve operating apparatus previously proposed by the present applicant. This variable valve operating apparatus has a rod-shaped link, a rocker arm, and a ring-shaped link, which are a plurality of link parts that link a drive shaft that is rotationally driven by an internal combustion engine and a swing cam that operates an intake / exhaust valve. is doing. The rocker arm is swingably attached to a circular control eccentric cam provided eccentric to the control shaft. By rotating the control shaft by the actuator, the support position of the rocker arm with respect to the engine body changes, and the valve lift characteristics of the intake and exhaust valves are continuously changed and controlled.
[0004]
In addition, in Patent Document 1 described above, in order to improve lubricity in a large lift setting state often used in a high rotation range and a high load range, a ring-shaped link and a rocker arm And a technique for supplying lubricating oil to the connecting portion between the rod-shaped link and the rocker arm.
[0005]
[Patent Document 1]
JP 2000-213316 A (paragraphs [0052], [0060], etc.)
[0006]
[Problems to be solved by the invention]
In the small lift setting state suitably used in the low load range, the oil supply pressure of the oil pump driven by the crankshaft of the engine is also low, so that it is difficult to sufficiently supply the lubricating oil to the above-described connection parts, There is a possibility that the fuel consumption performance is lowered due to the increase in the size of the oil pump or the increase in the amount of lubricating oil. Also, in the small lift setting state often used in the low rotation range, the movement of the moving parts such as the crankshaft and link parts is slow, so the oil in the oil pan is lifted up by the crankshaft etc. and scattered in all directions. (Mist type), and splash type lubrication in which each part is lubricated with this mist type lubricating oil cannot be expected so much, and lubrication tends to be insufficient.
[0007]
The present invention has been made in view of such a problem, and a main object of the present invention is to provide a variable valve operating apparatus for an internal combustion engine capable of appropriately supplying lubricating oil to a predetermined lubricating portion.
[0008]
[Means for Solving the Problems]
A variable valve mechanism that changes the valve lift characteristics of the intake and exhaust valves is provided. Lubricating oil supply means for supplying lubricating oil toward a predetermined lubricating portion of the variable valve operating mechanism is provided only in the small lift setting state by the variable valve operating mechanism. When the lubricating oil supply means has a first oil passage to which lubricating oil is supplied from the engine body side, and a second oil passage having one end opened toward the lubricating portion, and in the small lift setting state Only, the first oil passage and the second oil passage are set to communicate with each other.
[0009]
【The invention's effect】
Only when a small lift setting is likely to result in insufficient lubrication, the above-mentioned lubrication can be achieved without increasing the amount of lubricating oil or increasing the size of the oil pump by supplying lubricating oil toward a predetermined lubrication site. The part can be properly lubricated.
[0010]
DETAILED DESCRIPTION OF THE INVENTION
A preferred embodiment of a variable valve operating apparatus for an internal combustion engine according to the present invention will be described below with reference to the drawings.
[0011]
1 to 4 show a variable valve mechanism 11 that continuously changes both the valve lift characteristics of the intake valve 12, specifically, both the valve lift amount and the operating angle. The variable valve mechanism 11 includes a plurality of link parts that link a drive shaft 13 that is rotationally driven by an internal combustion engine and a swing cam 20 that serves as a valve operating cam that operates the intake valve 12, and one of the plurality of link parts. And a support position changing means for changing the valve lift characteristic of the intake valve 12 by changing the support position of the rocker arm 18 as a variable link part.
[0012]
The drive shaft 13 is rotatably supported on the cylinder head 10 by a bearing bracket 14 or the like, and extends in the cylinder row direction directly above the valve lifter 19 of the intake valve 12. In FIG. 1, only a pair of intake valves 12 corresponding to one cylinder is illustrated in a simplified manner. The drive shaft 13 is connected to a crankshaft (not shown) via a belt or a chain, and rotates in conjunction with the crankshaft. A circular drive eccentric cam 15 is integrally formed or fixed to the drive shaft 13 for each cylinder. The center X of the drive eccentric cam 15 is eccentric and offset with respect to the center Y of the drive shaft 13.
[0013]
The swing cam 20 is swingably attached to the drive shaft 13 for each cylinder. Each swing cam 20 integrally protrudes radially outward from the journal portion 20b formed with a bearing surface for the drive shaft 13, and pushes down the valve lifter 19 of the intake valve 12. And two cam bodies 20a.
[0014]
The support position changing mechanism has a control shaft 16 that extends in the cylinder row direction in parallel with the drive shaft 13 and is rotatably supported by the bearing bracket 14 or the like toward the cylinder head 10 as the engine body. A circular control eccentric cam 17 is integrally formed or fixed to the control shaft 16 for each cylinder. The center P1 of the control eccentric cam 17 is eccentric and offset with respect to the center P2 of the control shaft 16. The rocker arm 18 is swingably attached to the control eccentric cam 17. That is, the rocker arm 18 has a bearing surface 18a for the control eccentric cam 17, and swings with the center P1 of the control eccentric cam 17 as a support fulcrum.
[0015]
In addition to the rocker arm 18 described above, the plurality of link parts include a ring-shaped first link 25 that connects the drive eccentric cam 15 and one end of the rocker arm 18, the other end of the rocker arm 18, and the swing cam 20. And a rod-shaped second link 26 that is connected. A bearing surface for the drive eccentric cam 15 is formed at one end of the first link 25. The other end of the first link 25 and one end of the rocker arm 18 are connected by a first connecting pin 27 that passes through both of them. One end of the second link 26 and the other end of the rocker arm 18 are connected by a second connecting pin 28 that passes through both of them. The other end of the second link 26 and the tip of one cam main body 20a of the swing cam 20 are connected by a third connecting pin 29 that passes through both of them. All of the first connection part by the first connection pin 27, the second connection part by the second connection pin 28, and the third connection part by the third connection pin 29 have a full float connection structure.
[0016]
A motor actuator 51 is connected to the control shaft 16 as a driving means for rotating and holding the control shaft 16. Specifically, the worm gear 52 provided at the tip of the output shaft 51 a of the motor actuator 51 and the worm wheel 50 provided at the rear end of the control shaft 16 are engaged with each other. The operation of the motor actuator 51 is controlled by a control unit (not shown). When the rotation angle of the control shaft 16 is changed by the motor actuator 51, the control eccentric cam 17 serving as the rocking fulcrum of the rocker arm 18 is applied to the control shaft 16. On the other hand, the support position of the rocker arm 18 with respect to the engine body changes due to rotational displacement, and the valve lift characteristics of the intake valve 12, specifically, both the valve lift amount and the operating angle are changed and controlled continuously and steplessly. . Preferably, the valve lift characteristic, that is, the angle of the control shaft 16 is feedback-controlled based on the output of the angle sensor 71 that detects the angle of the control shaft 16.
[0017]
Next, the lubrication system of the variable valve mechanism 11 according to the first embodiment of the present invention will be described. In the variable valve mechanism 11, particularly a bearing portion that needs lubrication is lubricated through an internal oil passage of the cylinder head 10 using an oil pump (not shown) driven by a crankshaft. Oil is pumped.
[0018]
For example, lubricating oil is always supplied to the bearing portion between the outer peripheral surface of the drive eccentric cam 15 and the bearing surface of the first link 25 via an internal oil passage 31 formed inside the drive shaft 13. The bearing part is forcibly lubricated.
[0019]
Similarly, lubricating oil is always supplied to the bearing portion between the outer periphery of the control eccentric cam 17 and the bearing surface 18a of the rocker arm 18 via the first oil passage 33 formed inside the control shaft 16, This bearing portion is forcibly lubricated. The first oil passage 33 includes an axial oil passage 34 that extends in the axial direction, and a radial oil passage 35 that connects the axial oil passage 34 and the outer peripheral surface of each control eccentric cam 17. Lubricating oil is supplied to the directional oil passage 34 from the cylinder head side.
[0020]
A second oil passage 36 is formed in the rocker arm 18. The second oil passage 36 extends in the radial direction, and has one end opened to the bearing surface 18 a of the rocker arm 18 and the other end opened toward the second connection portion by the second connection pin 28. .
[0021]
FIG. 5 (a) corresponds to a large lift setting state in which the valve lift amount and the operating angle are maximized. In this large lift setting state, the rocker arm 18 is in the base circle according to the rotation of the crankshaft (1). It swings within the range of the posture (2) at the maximum lift from the posture. FIG. 5B corresponds to a small lift setting state in which the valve lift amount and the operating angle are minimum. In this small lift setting state (b), the rocker arm 18 is in the base circle according to the rotation of the crankshaft. It swings within the range of the posture of (3) from the posture of (4) at the time of maximum lift.
[0022]
As shown in the figure, the angle of the control shaft 16 differs by approximately 90 ° between the small lift setting state and the large lift setting state. As the center P1 of the control eccentric cam 17 that is the support fulcrum of the rocker arm 18 approaches the center Y of the drive shaft 13, the second connecting pin 28 approaches the swing cam 20 side, and both the valve lift amount and the operating angle are increased. As the center P1 of the control eccentric cam 17 is further away from the center Y of the drive shaft 13, the second connecting pin 28 is further away from the swing cam 20, and the valve lift amount and the operating angle are increased. Both become smaller (that is, approach the small lift setting state).
[0023]
FIG. 6 shows the posture of the rocker arm 18 with respect to the control shaft 16. As shown in the figure, the rocking range of the rocker arm 18 with respect to the control shaft 16 is large between (1) to (2) when the large lift is set and (3) to (4) when the small lift is set. Is different.
[0024]
In this embodiment, as shown in FIGS. 5 and 6, the second oil passage 36 has a diameter of the control shaft 16 only in the small lift setting state and in the vicinity of the maximum lift time (4) that is the lift section. It is set to communicate with the directional oil passage 35. Therefore, only in the lift section in the small lift setting state, the lubricating oil passes through the axial oil passage 34, the radial oil passage 35, and the second oil passage 36 to the second connecting portion by the second connecting pin 28. It is supplied and scattered, and this connecting portion can be sufficiently lubricated.
[0025]
In the engine operation range using the small lift setting state, the engine speed is low, so the hydraulic pressure by the oil pump that operates using the rotational power of the crankshaft of the engine is low, and the operation of the crankshaft, link parts, etc. Since the speed is also slow, the above-described spray-type lubrication with the mist-like lubricating oil cannot be expected so much and the lubrication may be insufficient. In particular, in this embodiment, the second connecting portion by the second connecting pin 28 is often located on the upper side of the engine as compared with the first connecting portion, and the lubricating oil is difficult to be scattered, so that lubrication is likely to be insufficient. Therefore, in this embodiment, only when the lift section is in the small lift setting state and the necessity of lubrication is high, the lubricating oil is positively supplied to the second connecting portion, and this portion is lubricated. .
[0026]
In the large lift setting state, the engine speed is high and the operating speed of the moving parts is fast, so that the spraying and atomization of the lubricating oil is promoted, and the lubricating effect by this mist-like lubricating oil is high. Therefore, even if the lubricating oil is not directly supplied to the connecting portion by the second connecting pin 28 via the oil passages 33 and 36, insufficient lubrication will not be caused. Further, in the large lift setting state, the load acting on the bearing portions of the rocker arm 18 and the control eccentric cam 17 that are oscillating is higher than that in the small lift setting state, and therefore the necessity for lubrication is high. According to the present embodiment, in the large lift setting state, the radial oil passage 35 and the second oil passage 36 do not communicate with each other, and all of the lubricating oil supplied via the radial oil passage 35 is substantially. It will be used for lubrication of the bearing portion between the bearing surface 18a of the rocker arm 18 and the control eccentric cam 17, and this bearing portion can be well lubricated.
[0027]
The axial oil passage 34 and the radial oil passage 35 of the control shaft 16 are originally formed to supply lubricating oil to the bearing portions of the rocker arm 18 and the control eccentric cam 17, and are on the control shaft 16 side. No additional processing will occur. That is, the lubricating oil can be forcibly supplied to the connecting portion by the connecting pin only by forming the second oil passage 36 in the rocker arm 18.
[0028]
FIG. 7 shows a second embodiment of the present invention. In the second embodiment, as the second oil passage formed in the rocker arm 18, the third oil has one end opened to the bearing surface 18 a and the other end opened toward the first connection portion by the first connection pin 27. A path 36 </ b> A and a fourth oil path 36 </ b> B having one end opened to the bearing surface 18 a and the other end opened toward the second coupling portion by the second coupling pin 28 are formed. The fourth oil passage 36B is formed at the same position as the second oil passage 36 of the first embodiment. Further, as a radial oil passage of the first oil passage formed in the control shaft 16, a first radial oil passage 35A connecting the axial oil passage 34 and the third oil passage 36A of the first oil passage, and a shaft A second radial oil passage 35B that connects the directional oil passage 34 and the fourth oil passage 36B is formed.
[0029]
As shown in the figure, the first radial oil passage 35A and the third oil passage 36A communicate with each other only in the small lift setting state and in the vicinity of the maximum lift in the lift section, and the second radial oil The path 35B and the fourth oil path 36B are set to communicate with each other. Further, since the third oil passage 36A and the fourth oil passage 36B are disposed on substantially opposite sides across the center P1 of the control eccentric cam 17, the third oil passage 36A communicates with the second radial oil passage 35B. The fourth oil passage 36B does not communicate with the first radial oil passage 35A.
[0030]
According to the second embodiment, as in the first embodiment, the lubricating oil can be appropriately supplied to the connecting portion by the second connecting pin 28, and the lubricating portion of the second connecting pin 28 Similarly, the lubricating oil can be appropriately supplied also to the connecting portion by the first connecting pin 27.
[0031]
As described above, the present invention has been described based on the specific embodiments, but the present invention is not limited thereto. For example, the present invention may be applied to a variable valve apparatus that changes the valve lift characteristics of an exhaust valve.
[Brief description of the drawings]
FIG. 1 is a schematic perspective view showing a variable valve mechanism according to the present invention.
2 is a cross-sectional view of the variable valve mechanism in FIG. 1;
FIG. 3 is a side view corresponding to the variable valve mechanism in FIG. 1;
FIG. 4 is a cross-sectional view of the vicinity of a connection portion by a first connection pin.
FIG. 5 is an explanatory diagram of a large lift setting state (a) and a small lift setting state (b) according to the first embodiment.
FIG. 6 is an explanatory diagram showing the posture of the rocker arm with respect to the control shaft according to the first embodiment.
FIG. 7 is an explanatory diagram showing the posture of the rocker arm with respect to the control shaft according to the second embodiment.
[Explanation of symbols]
10 ... Cylinder head (engine body)
DESCRIPTION OF SYMBOLS 11 ... Variable valve mechanism 12 ... Intake valve 13 ... Drive shaft 15 ... Drive eccentric cam 16 ... Control shaft (support position change mechanism)
17 ... Control eccentric cam (support position changing mechanism)
18 ... Rocker arm (variable link parts)
18a ... Bearing surface 20 ... Swing cam (valve operating cam)
25 ... 1st link (link parts)
26 ... Second link (link parts)
27 ... 1st connecting pin 28 ... 2nd connecting pin 33 ... 1st oil path 34 ... Axial oil path 35 ... Radial direction oil path 35A ... 1st radial direction oil path 35B ... 2nd radial direction oil path 36 ... 2nd Oil passage 36A ... third oil passage 36B ... fourth oil passage

Claims (6)

A variable valve mechanism that changes the valve lift characteristics of the intake and exhaust valves;
Only when the small lift setting state by the variable valve mechanism, have a, and a lubricating oil supply means for supplying lubricating oil towards the predetermined lubrication sites of the variable valve mechanism,
When the lubricating oil supply means has a first oil passage to which lubricating oil is supplied from the engine body side, and a second oil passage having one end opened toward the lubricating portion, and in the small lift setting state Only, the variable valve operating apparatus of the internal combustion engine set so that the said 1st oil path and the 2nd oil path may communicate . The lubricating oil supply means, the lift section of the small lift settings only variable of an internal combustion engine according to claim 1 in which the a first oil passage and the second oil passage is configured so as to communicate Valve device. The variable valve mechanism includes a plurality of link parts that link a drive shaft that is rotationally driven by an internal combustion engine and a valve operating cam that operates intake and exhaust valves, and a variable link part that is one of the plurality of link parts. A support position change mechanism that changes the valve lift characteristics of the intake and exhaust valves by changing the support position of
A first oil passage is formed inside the support position changing mechanism,
The variable valve operating apparatus for an internal combustion engine according to claim 2, wherein a second oil passage is formed inside the variable link part. The support position changing mechanism includes a control shaft that is rotatably supported by the engine body, a circular control eccentric cam that is provided eccentric to the control shaft, and a drive unit that rotates and holds the control shaft. Have
The valve operating cam is a swing cam that is swingably attached to the drive shaft,
The variable link part is a rocker arm in which a bearing surface for the control eccentric cam is formed,
A plurality of link parts, a first link connecting the drive eccentric cam provided eccentric to the drive shaft and one end of the rocker arm, and a second link connecting the other end of the rocker arm and the swing cam; Have
The variable valve operating apparatus for an internal combustion engine according to claim 3, wherein the lubrication part is at least one of a first connection part between the rocker arm and the first link or a second connection part between the rocker arm and the second link. The first oil passage has an axial oil passage extending in the axial direction inside the control shaft, and a radial oil passage connecting the axial oil passage and the outer periphery of the control eccentric cam,
5. The variable valve operating apparatus for an internal combustion engine according to claim 4, wherein one end of the second oil passage opens on a bearing surface of the rocker arm, and the other end opens toward the first connection portion or the second connection portion. The second oil passage has a third oil passage that opens toward the first connection portion, and a fourth oil passage that opens toward the second connection portion,
A radial direction oil passage of the first oil passage is a first radial direction oil passage connecting the axial oil passage and the third oil passage, and a second radial direction connecting the axial oil passage and the fourth oil passage. The variable valve operating apparatus for an internal combustion engine according to claim 5, further comprising an oil passage.

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