JP3917747B2 - Valve operating device for internal combustion engine - Google Patents

Description

[0001]
BACKGROUND OF THE INVENTION
The present invention relates to a valve operating apparatus for an internal combustion engine, and more particularly to a valve operating apparatus that opens and closes an engine valve by a swing cam.
[0002]
[Prior art]
As this type of conventional valve operating device for an internal combustion engine, one described in SAE 970338 (General, Motors Corp) is known.
[0003]
The outline will be described with reference to FIG. 12. The drive shaft 1 is disposed along the front-rear direction on the cylinder head of the engine, and is driven to rotate by the crankshaft of the engine. The drive shaft 1 is swingably supported by the drive shaft 1. For example, the swing cam 4 that slides against the upper surface 3a of the valve lifter 3 of the intake valve 2 to open the intake valve 2 against the spring force of a valve spring (not shown), and the drive shaft 1 swing. A transmission mechanism 5 is provided between the cam 4 and the cam 5 to convert the rotational force of the drive shaft 1 into a lift force and transmit the lift force to the swing cam 4. The transmission mechanism 5 includes a first spur gear 6 fixed to the outer periphery of the drive shaft 1, a crankshaft 7 disposed above the first spur gear 6, and a first spur gear fixed to the crankshaft 7. The second spur gear 8 meshes with the spur gear 6, and a connecting link 10 that links the crankshaft 7 and the swing cam 4 via a connecting pin 9.
[0004]
Then, as the drive shaft 1 and the first spur gear 6 rotate in one direction (arrow), the second spur gear 8 and the crankshaft 7 rotate to cause the connecting cam 10 to swing the swing cam 4 in the arrow direction. Thus, the swing cam 4 is opened and closed by pressing or releasing the pressure against the spring force of the valve spring while the lower cam surface 4a is in sliding contact with the upper surface 3a of the valve lifter 3. It has become. Therefore, the valve lift characteristic can be obtained as a relatively large lift characteristic as shown in FIG. 14A.
[0005]
[Problems to be solved by the invention]
By the way, in the conventional rocking device, the rotation direction (arrow) of the drive shaft 1 and the rocking direction from the base region 4b to the maximum lift point 4c on the cam surface 4a of the rocking cam 4, that is, on the lift-up side. Oscillating in the same direction (broken arrows in FIGS. 12 and 13A). For this reason, the lift characteristic immediately after reaching the maximum lift point 4c from immediately before reaching the maximum lift point 4c tends to become unstable as shown in FIG. 14B.
[0006]
That is, at the position immediately before the maximum lift point 4c, the swing cam 4 is pushed down in the clockwise direction in the drawing by the connecting pin 9 as shown in FIG. 13A. At this time, the swing cam 4 is moved by the spring force F of the valve spring. The frictional force μF in the right direction in the figure is generated on the contact surface with the valve lifter. Next, immediately after the swing cam 4 passes the maximum lift point 4c and the moving direction of the connecting pin 9 is reversed as shown in FIG. 13B, the spring force F of the valve spring counteracts the swing cam 4 counterclockwise. Try to lift in the direction. However, since the direction of the frictional force μF with the valve lifter 3 is reversed, the μF tries to prevent the swing cam from returning counterclockwise. Moreover, μ at this time is a relatively large value because the rocking speed of the rocking cam is extremely small.
[0007]
Further, since the rotation direction of the drive shaft 1 and the lift direction of the swing cam 4 are the same, the frictional force μf between the both 1 and 4 acts to rotate the swing cam 4 in the same clockwise direction. There is also a force in the direction of so-called rotation.
[0008]
For this reason, the swing cam 4 is restricted from smoothly rotating in the counterclockwise direction immediately after the maximum lift position, and as a result, the lift characteristics near the maximum lift are partially as shown in FIG. 14B as described above. This tends to be unstable, and the accuracy of the lift may deteriorate.
[0009]
In particular, when the clearance between the swing cam 4 and the connecting pin 9 is large, the range (backlash) in which the swing cam 4 can move with respect to the connecting pin 9 is expanded. May become noticeable.
[0010]
Immediately after the maximum lift point 4c of the oscillating cam 4, the frictional force μF between the oscillating cam 4 and the valve lifter 3 decreases as the relative speed between the two increases, so that the deterioration of the lift characteristics is eliminated. .
[0011]
[Means for Solving the Problems]
The present invention has been devised in view of the technical problem of the conventional valve gear, and the invention according to claim 1 is driven to rotate by a crankshaft of an engine, and an eccentric drive cam is fixed to the outer periphery. A valve operating apparatus for an internal combustion engine, comprising: a drive shaft; and a swing cam that is swingably provided in a predetermined angle range and that opens and closes an engine valve by a swing force transmitted from the drive cam via a transmission mechanism The swing cam is supported on the drive shaft in a swingable manner, and the rotation direction of the drive shaft and the swing direction from the maximum lift position of the swing cam with respect to the engine valve to the lift-down side are set to be the same. It is characterized by that.
[0012]
According to the present invention, since the rotation direction of the drive shaft and the swing direction of the swing cam from the maximum lift position to the lift-down side are the same, the swing cam is lifted by the moment due to the frictional force μf between the two. It can be quickly swung in the reverse direction from the position.
[0013]
According to a second aspect of the present invention, the transmission mechanism includes a rocker arm having one end linked to the drive cam and the other end linked to the swing cam to transmit the rotational driving force of the drive cam to the swing cam. It is characterized by that.
[0014]
According to a third aspect of the present invention, the transmission mechanism includes a link arm that links the one end of the rocker arm and the drive cam.
[0015]
The invention according to claim 4 is characterized in that the transmission mechanism includes a link rod that links the other end of the rocker arm and the swing cam.
[0016]
The invention described in claim 5 is characterized in that a variable mechanism is provided for changing the cam lift amount of the rocking cam by changing the rocking fulcrum position of the rocker arm.
[0017]
The invention described in claim 6 is characterized in that a follower is disposed between the swing cam and the engine valve so that the swing cam is in sliding contact with the engine valve to transmit lift.
[0018]
The invention described in claim 7 is characterized in that the follower is a roller follower.
[0019]
The invention according to claim 8 is characterized in that lubricating oil is supplied via an oil supply passage between the swing cam and the follower in the lift region including at least the maximum lift of the swing cam.
[0020]
According to the ninth aspect of the present invention, the oil supply passage is formed in the oil passage formed in the direction of the internal axis of the drive shaft, the oil hole formed in the peripheral wall of the drive shaft along the radial direction, and the swing cam. It is formed, and one end is constituted by the oil hole and the other end is constituted by an oil passage hole opened in the cam surface.
[0021]
DETAILED DESCRIPTION OF THE INVENTION
Hereinafter, a first embodiment of the valve gear of the present invention will be described in detail with reference to FIGS. The valve operating apparatus according to this embodiment is provided with a variable mechanism that includes two intake valves per cylinder and makes the valve lift of the intake valves variable according to the engine operating state.
[0022]
That is, this valve operating device is rotatably supported by a pair of intake valves 12 and 12 slidably provided on a cylinder head 11 via a valve guide (not shown) and a bearing 14 above the cylinder head 11. A hollow drive shaft 13, two drive cams 15 and 15, which are eccentric rotary cams fixed to the drive shaft 13 by press-fitting or the like, and swingably supported by the drive shaft 13, each intake valve Oscillating cams 17 and 17 for slidably contacting the upper surfaces 16a and 16a of the valve lifters 16 and 16 which are followers disposed at the upper ends of the 12 and 12 to open the intake valves 12 and 12; Linked between the swing cams 17 and 17, a transmission mechanism 18 that transmits the rotational force of the drive cam 15 as the swing force of the swing cams 17 and 17, and a variable that makes the operating position of the transmission mechanism 18 variable. And a mechanism 19.
[0023]
The drive shaft 13 is arranged along the longitudinal direction of the engine and is rotated from the crankshaft of the engine via a driven sprocket (not shown) provided at one end, a timing chain wound around the driven sprocket, and the like. The force is transmitted, and the rotation direction is set in the counterclockwise direction in FIG.
[0024]
The bearing 14 is provided at the upper end portion of the cylinder head 11 to support the upper portion of the drive shaft 13, and the bearing 14 is provided at the upper end portion of the main bracket 14a to rotatably support a control shaft 32 described later. The brackets 14a and 14b are fastened together from above by a pair of bolts 14c and 14c.
[0025]
As shown in FIG. 4, both the drive cams 15 are substantially ring-shaped, and are composed of a small-diameter cam main body 15a and a flange portion 15b integrally provided on the outer end surface of the cam main body 15a. A drive shaft insertion hole 15c is formed penetrating in the direction, and the axis X of the cam body 15a is offset from the axis Y of the drive shaft 13 by a predetermined amount in the radial direction. Each drive cam 15 is press-fitted and fixed to both sides of the drive shaft 13 through the drive shaft insertion hole 15c so as not to interfere with the valve lifters 16 and 16, and both the cam main bodies 15a and 15a are fixed. The outer peripheral surfaces 15d and 15d are formed in the same cam profile.
[0026]
As shown in FIGS. 1, 6, and 7, the swing cam 17 has a substantially U shape, and is rotatably supported with a drive shaft 13 fitted into a substantially annular base end portion 20. A support hole 20a is formed through, and a pin hole 21a is formed through the cam nose 21 at one end. Further, a cam surface 22 is formed on the lower surface of the swing cam 17, and a base circle surface 22a on the base end portion 20 side, a ramp surface 22b extending from the base circle surface 22a to the cam nose portion 21 side in an arc shape, and the lamp A lift surface 22d is formed from the surface 22b to the top surface 22c of the maximum lift on the distal end side of the cam nose portion 21, and the base circle surface 22a, the ramp surface 22b , the top surface 22c, and the lift surface 22d are swung. The upper surface 16a of each valve lifter 16 is brought into contact with a predetermined position according to the swing position of the cam 17. That is, when viewed from the valve lift characteristics shown in FIG. 5, as shown in FIG. 1, the predetermined angle range θ1 of the base circle surface 22a becomes the base circle section, and the predetermined angle range θ2 from the base circle section θ1 of the ramp surface 22b changes. A so-called ramp section is set, and a predetermined angle range θ3 from the ramp section θ2 of the ramp surface 22b to the top surface 22c is set to be a lift section. The swing cam 17 is set in the same direction as the rotation direction of the drive shaft 13 in the direction in which the swing cam 17 is lifted down from the maximum lift position (top surface) and swings to the base circle surface 22a.
[0027]
The transmission mechanism 18 includes a rocker arm 23 disposed above the drive shaft 13, a link arm 24 that links the one end 23 a of the rocker arm 23 and the drive cam 15, the other end 23 b of the rocker arm 23, and a swing cam. 17 is provided.
[0028]
As shown in FIG. 3, each of the rocker arms 23 is bent in a substantially crank shape as viewed from above, and a cylindrical base portion 23c at the center is rotatably supported by a control cam 33 described later. Further, the one end portion 23a protruding from each outer end portion of each base portion 23c is formed with a pin hole 23d through which the pin 26 is fitted, while protruding from each inner end portion of each base portion 23c. The other end 23b is formed with a pin hole 23e into which a pin 27 connected to one end 25a of each link rod 25 is fitted.
[0029]
The link arm 24 includes an annular base 24a having a relatively large diameter and a projecting end 24b projecting at a predetermined position on the outer peripheral surface of the base 24a. A fitting hole 24c is formed in the outer peripheral surface of the cam main body 15a of the cam 15 so as to be rotatably fitted. On the protruding end 24b, a pin hole 24d through which the pin 26 is rotatably inserted is formed. Yes.
[0030]
Further, the link rod 25 is formed in a straight line having a predetermined length as shown in FIG. 1, and the other ends 23b of the rocker arm 23 and the ends of the swing cam 17 are provided at the circular ends 25a, 25b. Pin insertion holes 25c and 25d through which end portions of the pins 27 and 28 press-fitted into the pin holes 23e and 21a of the portion 21 are rotatably inserted are formed.
[0031]
In addition, snap rings 29, 30, 31 for restricting the axial movement of the link arm 24 and the link rod 25 are provided at one end of each pin 26, 27, 28.
[0032]
The variable mechanism 19 includes a control shaft 32 that is rotatably supported by the same bearing 14 above the drive shaft 13, and a control cam 33 that is fixed to the outer periphery of the control shaft 32 and serves as a swing fulcrum of the rocker arm 23. It has.
[0033]
Each of the control cams 33 has a cylindrical shape, and the position of the axis P1 is deviated from the axis P2 of the control shaft 32 by α as shown in FIG.
[0034]
The control shaft 32 extends in parallel with the drive shaft 13 and is controlled to rotate within a predetermined rotation angle range by an electromagnetic actuator (not shown) provided at one end, and the electromagnetic actuator is an engine It is driven by a control signal from a controller (not shown) that detects the operating state of the motor. The controller detects the current engine operating state based on detection signals from various sensors such as a crank angle sensor, an air flow meter, and a water temperature sensor, and outputs a control signal to the electromagnetic actuator.
[0035]
The operation of this embodiment will be described below. First, at the time of engine low speed and low load, the electromagnetic actuator is rotationally driven in one direction by a control signal from the controller. For this reason, the control cam 33 is held at the rotational position at the upper left of the axis P2 of the control shaft 32 as shown in FIGS. 6A and 6B, and the thick portion 33a is directed upward from the drive shaft 13. Move away. For this reason, the entire rocker arm 23 moves upward with respect to the drive shaft 13. For this reason, the end portions 23 of each rocking cam 17 are forcibly pulled up slightly via the link rod 25. Rotate left.
[0036]
6A and 6B, when the drive cam 15 rotates and pushes up the one end 23a of the rocker arm 23 via the link arm 24, the lift amount of the rocker cam 17 and the valve lifter is increased via the link rod 25. The lift amount L1 is relatively small as shown in FIG. 6B.
[0037]
Therefore, in such a low-speed and low-load region, as shown by the broken line in FIG. 8A, the valve lift amount becomes small, the opening timing of each intake valve 12 becomes late, and the valve overlap with the exhaust valve becomes small. For this reason, improvement in fuel consumption and stable rotation of the engine can be obtained.
[0038]
On the other hand, when the engine is shifted at high speed and high load, the electromagnetic actuator is rotationally driven in the opposite direction by a control signal from the controller. Therefore, as shown in FIGS. 7A and 7B, the control shaft 32 rotates the control cam 33 clockwise from the position shown in FIG. 6 to move the shaft center P1 (thick portion 33a) downward. For this reason, the entire rocker arm 23 is moved in the direction of the drive shaft 13 (downward), and the other end portion 23b presses the cam nose portion 21 of the swing cam 17 downward via the link rod 25. The entire moving cam 17 is rotated clockwise by a predetermined amount.
[0039]
Therefore, the contact position of the cam surface 22 with respect to the upper surface 16a of the valve lifter 16 of the swing cam 17 moves to the right position as shown in FIGS. For this reason, when the drive cam 15 rotates as shown in FIG. 7 and pushes up the one end 23a of the rocker arm 23 via the link arm 24, the lift amount L2 with respect to the valve lifter 16 increases as shown in FIG. 7B.
[0040]
Therefore, in such a high-speed and high-load region, the cam lift characteristic becomes larger than that in the low-speed and low-load region, the valve lift amount increases as shown by the solid line in FIG. 8A, and the opening timing of each intake valve 12 becomes earlier. The closing time is delayed. As a result, the intake charging efficiency is improved and a sufficient output can be secured.
[0041]
Thus, in the present embodiment, the opening / closing timing and valve lift amount of each intake valve 12 can be made variable, and the swing direction in the lift-down direction from the maximum lift position of the drive shaft 13 and the swing cam 17 can be changed. Since they are set to be the same, the following effects can be obtained.
[0042]
That is, first, immediately before the maximum lift, as shown in FIG. 9, the rocking cam 17 is pushed downward by the link rod 25 in the clockwise direction in the figure, and the rightward direction in the figure is interposed between the cam surface 22 and the valve lifter upper surface 16a. A frictional force μF is generated. Immediately after the maximum lift, the spring force F of the valve spring attempts to push the swing cam 17 back counterclockwise. On the other hand, the inverted frictional force μF tries to prevent it. However, the frictional force μf between the drive shaft 13 and the swing cam 17 acts in the lift-down direction (counterclockwise). For this reason, the swing cam 17 is quickly reversed in the counterclockwise direction in the drawing as the link rod 25 is pulled up.
[0043]
Therefore, as shown in FIG. 8B, the valve lift characteristics are slightly different from the design values (broken lines), but are not greatly deformed as in the conventional case, and are smooth characteristics substantially close to the design values. Become.
[0044]
As a result, even when the clearance between the link rod 25 and the pin 28 varies and the play becomes large, a stable valve lift characteristic can be obtained at all times.
[0045]
Further, in order to quickly push up the transmission mechanism such as the link rod 25 via the swing cam 17 by the moment caused by the frictional force μf as described above, not only the play of the link rod 25 and the pin 28 but also the link rod 25 and the rocker arm 23. Deformation of valve lift characteristics due to backlash at the connection point with the other end 23b of the head, backlash at the connection point between the link arm 24 and the drive cam 15, and backlash at the connection point between the link arm 24 and the rocker arm 23 one end 23a. Can be prevented.
[0046]
FIG. 11 shows a second embodiment of the present invention. In this embodiment, a roller follower 40 and a rocker arm 41 are interposed between the swing cam 17 and the intake valve 12 instead of a sliding follower as a valve lifter. It is a thing. That is, the rocker arm 41 has one end 41 a supported by the pivot 42 and the other end 41 b abutting against the valve stem upper end 12 a of the intake valve 12. On the other hand, the roller follower 40 has an annular shape, is rotatably supported through a support shaft 43 in a notch hole 41 c formed in the center of the rocker arm 41, and is a needle bearing provided between the support shaft 43. The cam surface 22 of the oscillating cam 17 abuts on the outer peripheral surface 40 a from above, and the rocker arm 41 is oscillated via the roller follower 40 by oscillating the oscillating cam 17. It is like that.
[0047]
The swing cam 17 is formed in the direction of the internal shaft of the drive shaft 13 as well as the swing direction of the lift-down side from the maximum lift position is set to be the same as the rotation direction of the drive shaft 13. An oil passage hole 46 communicating with an oil hole 45 formed along the radial direction is formed in the peripheral wall of the oil passage 44 and the drive shaft 13. The oil passage hole 46 is formed so as to penetrate from the inner surface of the support hole 20 a to substantially the center of the cam surface 22, and allows the lubricating oil in the oil passage 44 to pass between the cam surface 22 and the outer peripheral surface 40 a of the roller follower 40. To supply. That is, the opening end 46a of the oil passage hole 46 is directed to the sliding contact surface between the swing cam 17 and the roller follower 40 at the maximum lift.
[0048]
Therefore, according to this embodiment, the frictional force μF between the cam surface 22 and the outer peripheral surface of the roller follower 40 is caused by the smooth rotation of the roller follower 40 by the needle bearing 44 and the supplied lubricating oil. Therefore, the moment to rotate the swing cam 17 in the maximum lift direction (clockwise in the figure) immediately after the maximum lift as described above is reduced. Therefore, smoother valve lift characteristics can be obtained from the maximum lift position on the subsequent lift-down side.
[0049]
Moreover, since the lubricating oil is supplied between the cam surface 22 and the roller follower 40, the friction coefficient between the two at the time of the maximum lift becomes small. That is, the maximum lift oscillation speed of the oscillating cam 17 is extremely small, thus the friction coefficient of the sliding surface of the swing cam 17 and the roller follower 40 is increased, the lift decreasing speed of the swing cam 17 is lowered Although there is a possibility, the friction coefficient can be reduced by the lubricating oil between the two and 40 as described above, so that the lift reduction immediately after the maximum lift can be performed quickly, and as a result, the lift deformation can be reduced. .
[0050]
Or the method of supplying lubricating oil are generated in the present invention a second embodiment is not limited to the valve mechanism using a roller follower, it is applied to the valve mechanism using the sliding follower such as a valve lifter it can.
[0051]
The present invention is not limited to the above-described embodiment, and can be applied to a general valve operating apparatus in which the valve timing or the like cannot be made variable, or to a modification of the first or second embodiment. is there. Needless to say, the present invention can be applied to the exhaust valve side in addition to the intake valve.
[0052]
【The invention's effect】
As is clear from the above description, according to the valve gear according to the present invention, the rotation direction of the drive shaft and the swinging direction of the swing cam on the lift-down side are the same, so that the lift characteristics immediately after the maximum lift are smooth. And can be stabilized.
[0053]
In addition, the effects of the present invention can be exhibited particularly effectively for a multi-link mechanism having many connection points (backlash elements) such as a link arm, a link rod, or a rocker arm, as in the inventions of claims 2 to 4.
[0054]
Furthermore, according to the invention of claim 7, since the frictional force between the swing cam and the roller follower is further reduced, the valve lift characteristic can be controlled more smoothly and stably.
[0055]
According to the eighth and ninth aspects of the present invention, the lubricating oil is supplied to the sliding contact surface between the swing cam and the follower, particularly the sliding contact surface at the maximum lift of the swing cam. The coefficient becomes smaller. As a result, the lift deformation at the time of the lift-down can be reduced.
[Brief description of the drawings]
FIG. 1 is a cross-sectional view taken along line AA of FIG. 2 showing a first embodiment of the present invention.
FIG. 2 is a side view showing a part of the embodiment.
FIG. 3 is a plan view of the embodiment.
FIG. 4 is a perspective view showing a drive cam used in the embodiment.
FIG. 5 is a valve lift characteristic diagram corresponding to a base end surface and a cam surface of a swing cam.
6A and 6B are cross-sectional views taken along the line BB in FIG.
FIGS. 7A and 7B are cross-sectional views taken along line B-B in FIG.
FIG. 8A is a characteristic diagram of valve timing and valve lift of this embodiment, and B is an enlarged view of a Y portion of A.
FIG. 9 is an explanatory diagram showing the operation of the present invention.
FIG. 10 is an explanatory view showing the same operation.
FIG. 11 is a side view showing a second embodiment of the present invention.
FIG. 12 is a schematic view showing a conventional valve gear.
FIGS. 13A and 13B are partially enlarged views showing the operation of the conventional valve gear.
14A is a valve lift characteristic diagram of the conventional valve gear, and FIG. 14B is an enlarged view of an X part of A. FIG.
[Explanation of symbols]
DESCRIPTION OF SYMBOLS 11 ... Cylinder head 12 ... Intake valve 13 ... Drive shaft 15 ... Drive cam 16 ... Valve lifter (follower)
DESCRIPTION OF SYMBOLS 17 ... Swing cam 18 ... Transmission mechanism 19 ... Variable mechanism 20 ... Base part 21 ... One end part 22 ... Cam surface 23 ... Rocker arm 23a, 23b ... End part 24 ... Link arm 25 ... Link rod 40 ... Roller follower 44 ... Oil passage 45 ... Oil hole 46 ... Oil passage hole

Claims (9)

An engine valve is driven by a drive shaft that is rotationally driven by the crankshaft of the engine and has an eccentric drive cam fixed on the outer periphery, and a swinging force that is swingable within a predetermined range and transmitted from the drive cam via a transmission mechanism. In a valve operating apparatus for an internal combustion engine provided with a swing cam that opens and closes
It causes pivotably supported the rocking cam to the drive shaft, to the setting of the swinging direction of the lift-down side in the same from the maximum lift position relative to the engine valve in the rotational direction and oscillating cam of the drive shaft A valve operating apparatus for an internal combustion engine characterized by the above. The transmission mechanism includes a rocker arm that has one end linked to the drive cam and the other end linked to the swing cam to transmit the rotational driving force of the drive cam to the swing cam. 2. A valve operating apparatus for an internal combustion engine according to claim 1. 3. The valve operating apparatus for an internal combustion engine according to claim 2, wherein the transmission mechanism includes a link arm that links one end of the rocker arm and a drive cam. 4. The valve operating apparatus for an internal combustion engine according to claim 2, wherein the transmission mechanism includes a link rod that links the other end of the rocker arm and a swing cam. The valve operating apparatus for an internal combustion engine according to any one of claims 2 to 4, further comprising a variable mechanism that changes a cam lift amount of the rocking cam by changing a rocking fulcrum position of the rocker arm. The internal combustion engine according to any one of claims 1 to 5, wherein a follower is provided between the swing cam and the engine valve so that the swing cam is in sliding contact with the engine valve to transmit lift to the engine valve. Valve operating device. 7. The valve operating apparatus for an internal combustion engine according to claim 6, wherein the follower is a roller follower. 8. The operation of the internal combustion engine according to claim 6, wherein lubricating oil is supplied through an oil supply passage between the swing cam and the follower in a lift region including at least the maximum lift of the swing cam. Valve device. The oil supply passage is formed in an oil passage formed in an inner axial direction of the drive shaft, an oil hole formed in a peripheral wall of the drive shaft along a radial direction, and an oscillation cam, and one end of the oil supply passage 9. The valve operating apparatus for an internal combustion engine according to claim 8, wherein the oil hole comprises an oil passage hole having the other end opened to the cam surface.

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