JP5287327B2 - Valve operating device for internal combustion engine - Google Patents

Description

  The present invention relates to a valve gear for an internal combustion engine.

  Patent Document 1 discloses that an intake camshaft (exhaust side drive shaft) and an exhaust camshaft (exhaust side drive shaft) that rotate in synchronization with the rotation of the internal combustion engine have an intake side eccentric cam (eccentric cam) and an exhaust side eccentricity, respectively. A link arm (ring-shaped link) provided with a cam (control cam) and rotatably fitted on the outer circumference of the intake side eccentric cam, and a link arm rotatably fitted on the outer circumference of the exhaust side eccentric cam, A rocker arm that is swung by the rocker arm, and is rotatably supported by the intake camshaft, and is connected to the rocker arm via a link rod (rod-shaped link). An intake swing cam (oscillation cam) that opens and closes, and an exhaust cam that is provided on the exhaust camshaft and opens and closes the exhaust valve as the exhaust camshaft rotates, By providing a phase difference between the serial and the intake side eccentric cam and the exhaust-side eccentric cam, variable discloses a technique the lift amount of the intake valve.

JP 2000-213318 A

  However, in this patent document 1, since the link mechanism is comprised between the intake camshaft and the exhaust camshaft, there exists a problem that a link mechanism will enlarge.

  Therefore, a valve operating apparatus for an internal combustion engine according to the present invention includes a drive shaft that rotates in synchronization with the rotation of the internal combustion engine, a first eccentric cam and a second eccentric cam provided on the drive shaft, and a first eccentric cam. A first link arm that is rotatably fitted to the outer periphery, a second link arm that is rotatably fitted to the outer periphery of the second eccentric cam, and a link member connected to the first link arm and the second link arm; An engine valve is rotatably supported by a cam holding shaft arranged in parallel to the drive shaft, and is connected to the first link arm and the second link arm via a link member, and swings along with the link member. And a phase difference changing means for changing a phase difference between the rotation of the first eccentric cam and the rotation of the second eccentric cam, and the first eccentric cam and the second eccentric cam, The valve lift of the engine valve by making the phase difference of the engine variable It is characterized by variably controlling the.

  According to the present invention, by changing the phase difference between two eccentric cams on one axis, the apparatus can be reduced in size and a highly versatile variable valve independent of the type of the internal combustion engine can be constructed. Can do.

Explanatory drawing which looked at 1st Embodiment of this invention from the axial direction. Explanatory drawing of 1st Embodiment of this invention. Explanatory drawing of each cam part of the rocking cam in 1st Embodiment of this invention. The perspective view which shows the principal part of the drive shaft in the valve operating apparatus of the internal combustion engine which concerns on this invention. FIG. 5 is an explanatory view showing a cross section of the main part when the phase difference between the first axis and the second axis of the drive shaft is “0”, and an explanatory view showing a cross section along the line P-P in FIG. 4; Explanatory drawing which also showed the explanatory drawing which shows the cross section along the QQ line | wire of FIG. FIG. 5 is an explanatory diagram showing a cross section of the main part when the phase difference between the first axis and the second axis of the drive shaft is “45 deg”, and an explanatory diagram showing a cross section along the line P-P in FIG. 4; Explanatory drawing which also showed the explanatory drawing which shows the cross section along the QQ line | wire of FIG. Explanatory drawing which shows the valve lift characteristic of the valve operating apparatus of the internal combustion engine which concerns on this invention. It is explanatory drawing which shows the operating state of the valve operating apparatus of the internal combustion engine which concerns on this invention, Comprising: The explanatory drawing which each showed the peak lift state at the time of the maximum lift and the minimum lift, and an anti-peak lift state. Explanatory drawing which looked at 2nd Embodiment of this invention from the axial direction. Explanatory drawing of 2nd Embodiment of this invention. Explanatory drawing of each cam part of the rocking cam in 2nd Embodiment of this invention. Explanatory drawing which looked at 3rd Embodiment of this invention from the axial direction. Explanatory drawing of 3rd Embodiment of this invention. Explanatory drawing of each cam part of the rocking cam in 3rd Embodiment of this invention. Explanatory drawing which looked at 4th Embodiment of this invention from the axial direction. Explanatory drawing of 4th Embodiment of this invention. Explanatory drawing of each cam part of the rocking cam in 4th Embodiment of this invention.

  Hereinafter, an embodiment of the present invention will be described in detail with reference to the drawings.

  FIG. 1 is an explanatory view of an internal combustion engine valve operating apparatus according to a first embodiment of the present invention viewed in the axial direction, and FIG. 2 is a plan view of the internal combustion engine valve operating apparatus of the first embodiment of the present invention. It is explanatory drawing equivalent to.

  A valve operating apparatus for an internal combustion engine according to the present invention includes a drive shaft 1 rotatably supported on a cylinder head (not shown), and a circular first eccentric cam 2 fixed to the drive shaft 1 by press fitting or the like. The second eccentric cam 3, the first link arm 4 rotatably fitted to the outer periphery of the first eccentric cam 2, and the second link arm 5 rotatably fitted to the outer periphery of the second eccentric cam 3. A substantially L-shaped cam holding shaft 6 that is rotatably supported on the upper part of the cylinder head and is arranged in parallel to the drive shaft 1 and connected to the first link arm 4 and the second link arm 5. By being rotatably supported by the link member 7 and the cam holding shaft 6, the link member 7 is connected to the first link arm 4 and the second link arm 5 via the link member 7, and swings along with the link member 7. A swing cam 9 for opening and closing the intake valve 8 and a first bias Has a phase difference changing means (described in detail later) to change the phase difference between the rotating and the rotation of the second eccentric cam 3 of the cam 2.

  The eccentric amounts of the first eccentric cam 2 and the second eccentric cam 3 are set to be substantially the same. Moreover, the diameter of the sliding part of the 1st eccentric cam 2 which the 1st link arm 4 fits rotatably, and the diameter of the sliding part of the 2nd eccentric cam 3 which the 2nd link arm 5 fits rotatably. Are set to be substantially the same.

  The intake valve 8 is driven to open and close by a swing cam 9 via a valve rocker arm 10. The exhaust valve 11 is driven by a so-called direct acting type in which the exhaust cam 12 drives the exhaust valve 11 via the tappet 13. The exhaust cam 12 is fixed or integrally formed with the exhaust cam shaft 14 by press fitting or the like.

  The drive shaft 1 and the exhaust camshaft 14 are driven by an engine crankshaft (not shown) via a timing chain (or timing belt) (not shown) at the engine front end (not shown) and synchronized with the rotation of the engine. Then rotate.

  An annular portion 4 a of the first link arm 4 is rotatably fitted to the outer periphery of the first eccentric cam 2 of the drive shaft 1, and the tip of the arm portion 4 b extending from the annular portion 4 a and the link member 7. One end is connected through a connecting pin 16 so as to be swingable.

  An annular portion 5a of the second link arm 5 is rotatably fitted to the outer periphery of the second eccentric cam 3 of the drive shaft 1, and the tip of the arm portion 5b extending from the annular portion 5a and the link member 7 are connected. The intermediate part is connected through a connecting pin 17 so as to be swingable.

  The swing cam 9 and the other end of the link member 7 are connected via a connecting pin 18 so as to be swingable.

  That is, the link member 7 is disposed between the first eccentric cam 2 and the second eccentric cam 3 and connected to the first link arm 4, the second link arm 5, and the swing cam 9.

  The swing cam 9 has a configuration in which a pair of cam portions 9 a and 9 b corresponding to the intake valves 8 are integrated with each other, and is rotatably supported by the drive shaft 1. The cam portions 9a and 9b have a base circle surface where the lift amount is substantially zero and a cam surface extending along a predetermined curve so that the lift amount gradually increases from the base circle surface. These surfaces are configured to contact the valve rocker arm 10 in accordance with the swing position of the swing cam 9. The cam profile side of the cam portion 9a of the swing cam 9 and the other end of the link member 7 are connected via a connecting pin 18 so as to be swingable. As shown in FIG. 3, a hole portion 19 into which the connecting pin 18 is inserted is formed in the cam portion 9 a of the swing cam 9. Further, the cam profile of the swing cam 9 is assembled so as to be positioned in the direction opposite to the drive shaft 1.

  Here, the phase difference changing means described above is constituted by the drive shaft 1 and the intake side phase variable mechanism 21. This intake side phase variable mechanism 21 is provided in the interlocking mechanism via the timing chain described above. This comprises, for example, a known mechanism for relatively rotating the outer peripheral housing (not shown) around which the timing chain is wound and the inner peripheral rotor (not shown) fixed to the shaft end portion by hydraulic pressure, For example, it is already known from Japanese Patent Application Laid-Open No. 2007-170180.

  As the intake-side phase variable mechanism 21, various known types can be used, and a phase difference using an electromagnetic force or a phase difference using a motor may be used. Further, in order to change the phase difference between the crankshaft and the exhaust camshaft 14, an exhaust side phase variable mechanism 22 is also provided on the exhaust side. The exhaust side phase variable mechanism 22 has the same configuration as the intake side phase variable mechanism 21. 2 in FIG. 2 is a cam bracket.

  More specifically, the drive shaft 1 described above is positioned outside the first shaft 31 and the first shaft 31 and coaxially with the first shaft 31, as shown in FIGS. And a cylindrical second shaft 32. The first shaft 31 and the second shaft 32 are rotatably held on the same axis, and the first eccentric cam 2 is connected to the first shaft 31 by press-fitting a first press-fit pin 33. Has been. The second shaft 32 is provided with a long hole 34 corresponding to the phase conversion angle so as not to interfere with the first press-fit pin 33. In addition, the second eccentric cam 3 is connected to the second shaft 32 by press-fitting the second press-fit pin 35. The first shaft 31 is provided with a long hole 36 corresponding to the phase conversion angle so as not to interfere with the second press-fit pin 35.

  Thereby, by providing a phase difference between the first shaft 31 and the second shaft 32, an angular difference can be provided in the eccentric direction of the first eccentric cam 2 and the second eccentric cam 3. In other words, the phase difference changing means includes the drive shaft 1 and the intake-side phase variable mechanism 21, and the drive shaft 1 includes the first shaft 31 and the second shaft 32 arranged on the same axis, and the inner side. The first eccentric cam 2 is fixed to the first shaft 31, the second eccentric cam 3 is fixed to the outer second shaft 32, and the first shaft 31 is fixed by the intake side phase variable mechanism 21. By changing the phase difference between the first eccentric cam 2 and the second shaft 32, the phase difference between the rotation of the first eccentric cam 2 and the rotation of the second eccentric cam 3 is changed.

  The elongated holes 34 and 36 are formed so that at least there is no phase difference between the first eccentric cam 2 and the second eccentric cam 3.

  The first shaft 31 is coupled to the rotor of the intake side phase variable mechanism 21 described above, and the second shaft 32 is coupled to the housing of the intake side phase variable mechanism 21 described above. As a result, an angle difference is created between the rotor and the housing of the intake side phase varying mechanism 21, so that an angle difference can be provided between the first eccentric cam 2 and the second eccentric cam 3.

  The lift amount of the intake valve 8 can be controlled by making the phase difference between the first eccentric cam 2 and the second eccentric cam 3 variable. That is, the rotation center position of the first and second eccentric cams 2 and 3 is “A”, the center position of the first eccentric cam 2 is “B”, and the center position of the second eccentric cam 3 is “C”. The lift amount of the intake valve 8 is changed by changing the angle of ∠BAC, which is one of the inner angles of the triangle ABC formed by connecting the positions. More specifically, as shown in FIG. 7, the valve lift amount of the intake valve 8 increases as the angle of ∠BAC increases.

  FIG. 8 shows an operation state diagram of the above-described embodiment, and shows a peak lift state and an anti-peak lift state at the maximum lift and the minimum lift, respectively. From the maximum lift time to the minimum lift time, it can be seen that the rocking cam rocking angle at the peak lift (counterclockwise positive with respect to the X axis) is small due to the change in the angle of the ∠BAC. Thereby, the lift of the intake valve 8 can be changed.

  In the first embodiment of the present invention, since the phase difference between the two eccentric cams 2 and 3 can be changed on one shaft (drive shaft 1), the apparatus can be miniaturized. In addition, a highly versatile variable valve that does not depend on the type of the internal combustion engine can be constructed.

  The eccentric amount of the first eccentric cam 2 and the second eccentric cam 3 is substantially the same, the diameter of the sliding portion of the first eccentric cam 2 with which the first link arm 4 is rotatably fitted, and the second link. Since the diameter of the sliding portion of the second eccentric cam 3 with which the arm 5 is rotatably fitted is set to be substantially the same, the first eccentric cam 2 and the second eccentric cam 3 and the cam holding shaft 6 are set. Even after the assembly, the first link arm 4 and the second link arm 5 can be inserted into the drive shaft 1, and the assembly can be facilitated.

  Then, since there can be no phase difference between the first eccentric cam 2 and the second eccentric cam 3, the first eccentric cam 3, the second eccentric cam 3, and the cam holding shaft 6 are assembled. Since the first link arm 4 and the second link arm 5 can be inserted into the drive shaft, the assembly can be facilitated. Further, the assembly can be performed also when the first eccentric cam 2 and the second eccentric cam 3 are adjacent to each other.

  Further, since the cam profile of the swing cam 9 is located in the opposite direction to the drive shaft 1, it is possible to reduce the distance between the cam holding shaft 6 and the drive shaft 1, thereby reducing the size of the apparatus. be able to.

  Hereinafter, although other embodiment of this invention is described, about the component same as 1st Embodiment mentioned above, the same code | symbol is attached | subjected and the overlapping description is abbreviate | omitted.

  9 to 11 show a second embodiment of the present invention. The second embodiment has substantially the same configuration as the first embodiment described above, but in this second embodiment, the link member 7 in the first embodiment is replaced with three links 41, 42, 43. It has been.

  That is, the elongated first link 41 that connects the distal end of the arm portion 4 b of the first link arm 4 and the distal end of the arm portion 5 b of the second link arm 5, the distal end of the arm portion 4 b of the first link arm 4, and the swing cam 9. A long and narrow second link 42 that connects the cam portion 9a, and a long and narrow third link 43 that connects the tip of the arm portion 5b of the second link arm 5 and the cam portion 9b of the swing cam 9. The two links 41, 42, 43 are arranged so as to be offset from each other in the axial direction of the drive shaft 1.

  One end of the first link 41 is connected to the first link arm 4 and the second link 42 by a connecting pin 44, and the other end is connected to the second link arm 5 and the third link 43 by a connecting pin 45. Yes. One end side of the second link 42 is connected to the first link arm 4 and the first link 41 by a connecting pin 44, and the other end side is connected to the cam portion 9 a of the swing cam 9 by a connecting pin 46. One end side of the third link 43 is connected to the second link arm 5 and the first link 41 by a connecting pin 45, and the other end side is connected to the cam portion 9 b of the swing cam 9 by a connecting pin 47.

  The second link 42 and the third link 43 are respectively connected to the cam portions 9a and 9b of the swing cam 9 on an axis different from the rotation axis of the swing cam 9 and on the same axis. Yes. That is, the connecting pin 46 and the connecting pin 47 are located on the same axis as shown in FIG.

  Further, as shown in FIG. 11, the cam portion 9 a of the swing cam 9 is formed with a hole portion 48 into which the connection pin 46 is inserted, and the connection pin 47 is inserted into the cam portion 9 b of the swing cam 9. A hole 49 is formed.

  In the second embodiment as well, it is possible to obtain the same operational effects as the first embodiment described above, and by replacing the link member 7 in the first embodiment with three links 41, 42, 43, Manufacturing cost can be reduced.

  12 to 14 show a third embodiment of the present invention. The third embodiment has substantially the same configuration as that of the second embodiment described above, but the second link 42 and the third link 43 in the third embodiment are on different axes, and both swing. The shafts are connected to cam portions 9 a and 9 b of the swing cam 9 on axes different from the rotational axis of the moving cam 9. That is, the connecting pin 46 and the connecting pin 47 are offset as shown in FIG. Therefore, in the third embodiment, as shown in FIG. 14, a connecting pin 46 that connects the cam portion 9 a and the other end of the second link 42 is provided on the side opposite to the cam profile of the cam portion 9 a of the swing cam 9. A hole 48 to be inserted is formed.

  In such a third embodiment, the same operational effects as those of the second embodiment described above can be obtained, the connecting position between the second link 42 and the cam portion 9a of the swing cam 9, the third link 43, By shifting the connecting position of the swing cam and the cam portion 9b of the 9, it is possible to make the lengths of the second link 42 and the third link 43 the same, and an inexpensive apparatus configuration by sharing parts. Can be realized.

  15 to 17 show a fourth embodiment of the present invention. The fourth embodiment has substantially the same configuration as the second embodiment described above, but in this fourth embodiment, the second link 42 is opposed to the cam portion 9 a of the swing cam 9. 9 are connected on a rotating shaft.

  In the fourth embodiment, the same operational effects as those of the second embodiment described above can be obtained, and the cam portion 9a of the swing cam 9 can be connected to the second link 42 as compared with the second embodiment. Since there is no need to provide a hole for connection (see FIG. 17), the shape of the swing cam 9 can be simplified.

  The technical ideas of the present invention that can be grasped from the above-described embodiments will be listed together with their effects.

  (1) A drive shaft that is rotatably supported by the internal combustion engine body and rotates in synchronization with the rotation of the internal combustion engine, a first eccentric cam and a second eccentric cam provided on the drive shaft, and the first eccentric shaft A first link arm rotatably fitted to the outer periphery of the cam; a second link arm rotatably fitted to the outer periphery of the second eccentric cam; and a drive shaft rotatably supported by the internal combustion engine body. A cam holding shaft arranged in parallel to the first link arm, a link member connected to the first link arm and the second link arm, and a cam holding shaft rotatably supported by the first link arm and the first link arm. A swing cam that is connected to the two link arms via the link member and swings along with the link member to open and close the engine valve; rotation of the first eccentric cam; and rotation of the second eccentric cam; The phase difference between A phase difference changing means, and variably controls the valve lift of the engine valve by the phase difference between the second eccentric cam and the first eccentric cam is variable. As a result, by changing the phase difference between the two eccentric cams on one shaft, the apparatus can be reduced in size, and a highly versatile variable valve independent of the type of the internal combustion engine can be constructed.

  (2) In the valve operating apparatus for an internal combustion engine according to (1), the swing cam includes a first swing cam and a second swing cam so as to open and close two engine valves of the same cylinder, The link member includes a first link that connects the first link arm and the second link arm, a second link that connects the first link arm and the first swing cam, a second link arm, and a second link arm. It is composed of three links comprising a third link for connecting the swing cam. Thereby, the link member is replaced with three links, and an inexpensive apparatus configuration can be obtained.

  (3) In the valve operating apparatus for an internal combustion engine according to (2), the second link and the third link are on axes different from each other, and both are on axes different from the rotation axis of the swing cam. Thus, it is connected to the first rocking cam or the second rocking cam. In this way, by shifting the connection position of the second link and the first swing cam and the connection position of the third link and the second swing cam, the lengths of the second link and the third link are increased. It is possible to make them the same, and it is possible to make an inexpensive apparatus configuration by sharing parts.

  (4) In the valve operating apparatus for an internal combustion engine according to (1), the swing cam includes a first swing cam and a second swing cam so as to open and close two engine valves of the same cylinder. The link member includes a first link that connects the first link arm and the second link arm, a second link that connects the first link arm and the first swing cam, a second link arm, and a second link arm. A third link for connecting a swing cam, and the second link and the third link are arranged on axes different from each other on the first swing cam or the second swing link. The second link and the third link are connected to the swing cam, and one of the second link and the third link is connected to the swing cam on the rotation shaft of the swing cam, and the second link and the third link The other of the links is different from the rotating shaft of the swing cam In line, it is connected to the swing cam. As a result, of the first rocking cam and the second rocking cam, the rocking cam connected to the second link or the third link on the rotation shaft of the rocking cam has the second link or the third link. Since it is not necessary to provide a pin hole dedicated for the connection, it is possible to simplify the shape of one of the first swing cam and the second swing cam.

  (5) In the valve operating apparatus for an internal combustion engine according to (1), the first eccentric cam and the second eccentric cam have substantially the same amount of eccentricity, and the first link arm is rotatably fitted. The diameter of the sliding portion of the first eccentric cam and the diameter of the sliding portion of the second eccentric cam with which the second link arm is rotatably fitted are set to be substantially the same. As a result, the first link arm and the second link arm can be inserted into the drive shaft even after the first eccentric cam, the second eccentric cam and the cam holding shaft are assembled. can do.

  (6) In the valve operating apparatus for an internal combustion engine according to (1) or (5), the phase difference changing unit prevents at least a phase difference between the first eccentric cam and the second eccentric cam. be able to. As a result, the first link arm and the second link arm can be inserted into the drive shaft even after the first eccentric cam, the second eccentric cam and the cam holding shaft are assembled. can do. Furthermore, the assembly can be performed also when the first eccentric cam and the second eccentric cam are adjacent to each other.

  (7) In the valve operating apparatus for an internal combustion engine according to (1), the cam profile of the swing cam is located in a direction opposite to the drive shaft. As a result, the distance between the cam holding shaft and the drive shaft can be reduced, and the apparatus can be miniaturized.

  (8) In the valve operating apparatus for an internal combustion engine according to any one of (1) to (7), the drive shaft includes a first shaft and a second shaft arranged on the same axis, and the inner side. The first eccentric cam is fixed to the first shaft and the second eccentric cam is fixed to the outer second shaft, and the rotation of the first shaft and the first A phase variable mechanism that changes a phase difference with respect to rotation of the second shaft, and the phase difference changing means includes the drive shaft and the phase variable mechanism. By changing the phase difference between the first axis and the second axis, the phase difference between the rotation of the first eccentric cam and the rotation of the second eccentric cam is changed.

DESCRIPTION OF SYMBOLS 1 ... Drive shaft 2 ... 1st eccentric cam 3 ... 2nd eccentric cam 4 ... 1st link arm 5 ... 2nd link arm 6 ... Cam holding shaft 7 ... Link member 8 ... Intake valve 9 ... Swing cam 10 ... Valve rocker arm 21 ... Intake side phase variable mechanism

Claims (8)

A drive shaft rotatably supported by the internal combustion engine body and rotating in synchronization with the rotation of the internal combustion engine;
A first eccentric cam and a second eccentric cam provided on the drive shaft;
A first link arm rotatably fitted on the outer periphery of the first eccentric cam;
A second link arm rotatably fitted on the outer periphery of the second eccentric cam;
A cam holding shaft rotatably supported by the internal combustion engine body and disposed parallel to the drive shaft;
A link member connected to the first link arm and the second link arm;
A swing that is rotatably supported by the cam holding shaft and is connected to the first link arm and the second link arm via the link member, and swings along with the link member to open and close the engine valve. A dynamic cam,
Phase difference changing means for changing a phase difference between the rotation of the first eccentric cam and the rotation of the second eccentric cam;
A valve operating apparatus for an internal combustion engine, wherein a valve lift amount of an engine valve is variably controlled by making a phase difference between the first eccentric cam and the second eccentric cam variable. The rocking cam comprises a first rocking cam and a second rocking cam to open and close two engine valves of the same cylinder,
The link member includes a first link that connects the first link arm and the second link arm, a second link that connects the first link arm and the first swing cam, a second link arm, and a second link arm. 2. The valve operating apparatus for an internal combustion engine according to claim 1, wherein the valve operating apparatus is constituted by three links including a third link connecting the swing cam.   The second link and the third link are different from each other on both the first rocking cam and the second rocking cam on different axes and on an axis different from the rotation axis of the rocking cam. The valve operating apparatus for an internal combustion engine according to claim 2, wherein the valve operating apparatus is connected. The rocking cam comprises a first rocking cam and a second rocking cam to open and close two engine valves of the same cylinder,
The link member includes a first link that connects the first link arm and the second link arm, a second link that connects the first link arm and the first swing cam, a second link arm, and a second link arm. A third link for connecting the swing cam, and three links,
The second link and the third link are connected to the first rocking cam or the second rocking cam on different axes, and the second link and the third link are connected to each other. One of them is connected to the swing cam on the rotation shaft of the swing cam, and the other of the second link and the third link is on an axis different from the rotation shaft of the swing cam. The valve operating mechanism for an internal combustion engine according to claim 1, wherein the valve operating mechanism is connected to the swing cam. The amount of eccentricity of the first eccentric cam and the second eccentric cam is substantially the same,
A diameter of a sliding portion of the first eccentric cam that the first link arm is rotatably fitted to, and a diameter of a sliding portion of the second eccentric cam that the second link arm is rotatably fitted; 2. The valve operating device for an internal combustion engine according to claim 1, wherein the two are substantially the same.   6. The valve operating apparatus for an internal combustion engine according to claim 1, wherein the phase difference changing unit can prevent at least a phase difference between the first eccentric cam and the second eccentric cam. 2. The valve operating apparatus for an internal combustion engine according to claim 1, wherein the cam profile of the swing cam is located in a direction opposite to the drive shaft with respect to the cam holding shaft .
The drive shaft includes a first shaft and a second shaft arranged on the same axis, the first eccentric cam is fixed to the inner first shaft, and the outer second shaft is fixed. And the second eccentric cam is fixed,
A phase variable mechanism that changes a phase difference between the rotation of the first shaft and the rotation of the second shaft;
The valve operating apparatus for an internal combustion engine according to any one of claims 1 to 7, wherein the phase difference changing means includes the drive shaft and the phase variable mechanism.

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