JP2007239470A - Variable valve gear for internal combustion engine - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To secure degree of freedom in layout of a variable lift mechanism capable of limiting change of large and small lift peak phase of lift characteristics variably controlled small. <P>SOLUTION: This device includes a roller 16 abutting on a drive cam 5a of a camshaft 5, and is provided with an oscillating cam 8 oscillating with having a fulcrum on a pivot shaft 17, a swing arm opening and closing an intake valve with accompanying oscillation of the oscillating cam, and a variable lift member variably controlling lift of the intake valve by oscillating to change position of the pivot shaft. The device is constructed to position a rotation center X of the roller, canter point Y of the pivot shaft and a contact point Z of the oscillating cam and the swing arm on a straight line when the variable lift member is oscillated in an oscillatable angle range under a condition where the drive cam is under a base circle condition. <P>COPYRIGHT: (C)2007,JPO&INPIT

Description

  The present invention relates to a variable valve operating apparatus for an internal combustion engine that variably controls a valve lift amount of an engine valve that is an intake valve or an exhaust valve.

  As a conventional variable valve operating apparatus for an internal combustion engine, one described in Patent Document 1 below is known.

  This variable valve operating device swings in a state where it is in sliding contact with an intake valve or exhaust valve, which is an engine valve of an internal combustion engine, via a lash adjuster, and lifts the engine valve along with the swing, A driving cam that is fixed to the camshaft, has an outer peripheral surface that abuts the rocking cam via a roller, and rotates following the camshaft to rock the rocking cam; Accordingly, a moving means for moving the swing center of the swing cam is provided.

Then, the moving means operates according to the engine operating state to move the swing center of the swing cam, thereby changing the angle of the swing cam when the rotation angle of the drive cam is a predetermined amount. Along with this, the region in sliding contact with the engine valve via the lash adjuster on the cam surface of the swing cam changes, thereby changing the lift amount of the engine valve and changing the opening / closing timing.
JP-A-6-74011

  However, in the conventional variable valve operating device, when the swing center of the swing cam is changed by the moving means according to the engine operating state, the cam surface of the swing cam at the same cam angle of the drive cam. The sliding contact position with respect to the upper surface of the lassia adjuster changes.

  For this reason, when the lift amount of the engine valve is changed from the large lift state to the small lift state, the peak lift phase of the lift characteristic changes to the advance side or the retard side. As a result, the lift characteristics of the intake valve or the exhaust valve may change greatly depending on the rotation direction of the camshaft.

  The present invention has been devised in view of the technical problem of each of the conventional variable valve gears. The invention according to claim 1 is, in particular, the range of the rotation angle of the drive cam is the variable lift. The member operates in a range including at least an intermediate lift amount that is a lift amount near the center of the lift variable range.

  According to this invention, when the variable lift member is controlled to an intermediate lift amount within the variable lift range, the center points and the contact points are arranged in a substantially straight line. Even if this changes, the change in the rotation center position of the roller can be minimized.

  As a result, when the lift amount of the engine valve is changed from the large lift state to the small lift state, the change in the peak lift position becomes small, and a large change in the lift characteristics can be suppressed.

  The intermediate lift amount of the lift variable range is not only the meaning of the intermediate operating angle between the maximum operating angle and the minimum operating angle, but also in the vicinity of the intermediate operating angle, and the center of curvature of the swing cam and the follower curvature center. The lift amount at the position where the two are connected in a straight line.

  The invention according to claim 2 is basically the same configuration as that of the invention according to claim 1, and in particular, the drive cam is in a state of a predetermined rotation angle range, and the lift variable member can be swung. The center of curvature of the follower, the center point of the swing center axis, and the contact point of the swing cam and the valve operating member are arranged substantially linearly when swung in an angular range. It is a feature. Therefore, this invention also has the same effect as the invention of claim 1.

  The invention according to claim 3 is a more specific configuration, wherein the drive cam is in a state of a predetermined rotation angle range, and the lift variable member is controlled to an intermediate lift amount in the lift variable range. In this case, the rotation center of the first roller, the center point of the swing center axis, and the rotation center of the second roller are arranged in a substantially straight line. Therefore, this invention can obtain the same effects as those of the first and second aspects of the invention.

  Embodiments 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. This embodiment is applied to a V-type 6-cylinder internal combustion engine having two intake valves per cylinder.

  That is, as shown in FIGS. 1 to 3, the variable valve operating apparatus of the present invention is an intake valve that is two engine valves per cylinder for opening and closing a pair of intake ports 2, 2 formed in the cylinder head 1. 3, 3, a camshaft 5 rotatably supported in the longitudinal direction of the engine via a bearing 4 at the upper end of the cylinder head 1, and one end abuts on each stem end 3 a, 3 a of the intake valve 3, 3. The swing arms 6 and 6 that are the valve actuating members, the hydraulic lash adjusters 7 and 7 that are held by the cylinder head 1 and abut the other end of the swing arm 6, and the swing arms 6 and 6 are interposed therebetween. A pair of swing cams 8 and 8 for opening and closing the intake valves 3 and 3, and a variable lift mechanism 9 for varying the valve lift of the intake valves 3 and 3 via the swing cams 8 and 8. It has.

  Each intake valve 3 is slidably held on the cylinder head 1 via a valve guide 10 and is formed between each spring retainer 11 fixed in the vicinity of each stem end 3 a and the inner upper surface of the cylinder head 1. It is urged | biased in the closing direction by each valve spring 12 elastically contacted between.

  The bearing 4 includes a frame-like member 4a that is placed and fixed on the upper end of the outer peripheral portion of the cylinder head 1, and a bracket 4b that is fastened to the upper surface of the frame-like member 4a with left and right bolts 13 together. The camshaft 5 is rotatably supported between semicircular bearing grooves 4c and 4d formed between opposing surfaces of the frame-like member 4a and the bracket 4b. In addition, the bearing 4 rotatably supports a semicircular bearing groove 4e, 4f facing a control shaft, which will be described later, disposed on the side of the camshaft 5.

  The camshaft 5 is integrally provided with two drive cams 5a and 5a per cylinder on the outer periphery so that the rotational force from the crankshaft is transmitted via a driven sprocket (not shown) provided at one end. It has become. Each of the drive cams 5a is formed in a general egg shape, and includes a substantially arc-shaped base circle portion 5b and a lift portion 5c protruding in a substantially triangular shape.

  Each of the swing arms 6 has a roller 15 provided in a holding hole 6a formed at the center thereof rotatably supported by a roller shaft 14 and a needle (not shown), and a lower surface of one end portion of each swing arm 6 The valve 3 is in contact with the stem end 3 a, and the arc-shaped lower surface of the other end is in contact with the spherical head of the plunger 7 b of the hydraulic lash adjuster 7.

  As shown in FIG. 1, the hydraulic lash adjuster 7 has a well-known structure, and has a bottomed cylindrical body 7 a fixed in a cylindrical holding groove 1 a formed in the cylinder head 1. A cylindrical retainer 7b having a communication path in the lower part is fixed, and the plunger 7c is provided on the upper part of the retainer 7b so as to be slidable up and down. A hydraulic chamber 7d is formed inside the retainer 7b, and a high-pressure chamber that is opened and closed via a check valve 7e that opens and closes the communication path is formed at the bottom of the body 7a. The hydraulic pressure chamber is supplied with hydraulic pressure from an oil passage 1b formed in the cylinder head 1.

  As the plunger 7c is lowered, the hydraulic oil in the hydraulic chamber pushes the check valve 7e open to supply hydraulic pressure to the high-pressure chamber, and the plunger 7c is lifted to raise one end of the swing arm 6 and each intake valve 3. The gap with the stem end 3a is always zero-adjusted.

  As shown in FIG. 3, each of the swing cams 8 is bent into a substantially L shape, and has a cam portion 8a at the lower end portion, and integrally has a substantially vertical shape from the upper end portion of the cam portion 8a. And an arm portion 8b. A cam surface 8c is formed on the lower surface of the cam portion 8a. A second roller 16 that abuts on the outer peripheral surface of each drive cam 5a is rotatably supported at the upper end of the arm 8b.

  Further, between the cam portion 8a and the arm portion 8b, pivot support holes 8d that pass through the pivot shaft 17 that is held by a variable lift member (to be described later) of the variable lift mechanism 9 and that serves as a swinging central shaft are formed. Yes. The pivot 17 is formed in a single shape that supports the two swing cams 8 and 8 so as to be swingable together.

  The cam surface 8c has one end surface on the arm portion 8b side serving as a base circle region, and the other end surface on the distal end portion side (cam nose portion side) serving as a lift region.

  The variable lift mechanism 9 is rotatable between the variable lift member 18 that changes the swing fulcrum via the balance shaft 17 of each swing cam 8 and the bearing grooves 4e and 4f of the bearing 4. A supported control shaft 19, two control cams 20 per cylinder integrally provided on the outer peripheral surface of the control shaft 19, and an electric actuator that controls the control shaft 19 to rotate forward and backward according to the engine operating state. 21 and an electronic controller 22 for controlling the driving of the electric actuator 21 and the swing cams 8 and 8 to bias the swing cams 8 and 8 toward the drive cams 5a and 5a. At the same time, it is mainly composed of a torsion spring 23 which is an urging means for urging the variable lift member 18 toward the control cam 20.

  As shown in FIGS. 1 to 3, each of the lift variable members 18 is formed by integrally forming an irregularly shaped metal plate material into a substantially U-shaped cross section by press molding, and fixed to the lower surface of the frame-shaped member 4a. The base 24 is swingably supported on the support bracket 27 by a pair of left and right support shafts 26, 26, and is integrally provided at the upper end of the base 18a, and is in contact with the outer peripheral surface of each control cam 20. The two rocking cams 8 and 8 are disposed on the inner side. The support bracket 27 has a circular arc portion 27a that bulges downward at the center lower portion, and a fixing hole 27b into which one end of each of the support shafts 26 and 26 is inserted and fixed at the central position of the circular arc portion 27a. 27b is formed. The support shafts 26 and 26 constitute a central axis.

  The base portion 24 is formed in a convex shape on the side surface, and support shaft holes 24a, 24a into which one end portions of the support shafts 26, 26 are inserted and fixed are formed below the left and right rising sides. In addition, support holes 24b and 24b through which the pivot shaft 17 of each swing cam 8 is supported are formed through the upper portions of the left and right sides.

  The distal end portion 25 is bent in a substantially U shape, and the distal end surfaces 25 a and 25 a are in contact with the outer peripheral surfaces of the control cams 20 and 20.

  As shown in FIG. 1, the control shaft 19 is disposed at a symmetrical position on the opposite side of the engine width direction at substantially the same height as the camshaft 5, and extends in the engine longitudinal direction. The electric actuator 21 connected to one end is controlled to rotate in the normal and reverse directions within a predetermined angle range according to the engine operating state, so that the control cams 20 are rotated together.

  Each of the control cams 20 is arranged such that the center P1 thereof is decentered by a predetermined amount from the axis P2 of the control shaft 23, and the rotation member 25 is eccentrically swung according to the rotation position. .

  As shown in FIG. 3, the torsion spring 23 is formed in a substantially U-shaped plane, and each end 23 a, 23 a that extends from the left and right torsion parts and is bent horizontally is provided to each swing cam 8. , 8 is inserted into each small hole 8e provided in the cam nose portion of the cam portion 8a, and the other end portion 23b bent in a U-shape is a distal end surface 25a of the distal end portion 25 of the lift variable member 18. It is held by the edge of. Therefore, the torsion spring 23 urges the rollers 16 and 16 of the swing cams 8 and 8 toward the outer peripheral surface of the drive cams 5 and 5, and the tip surfaces 25 a and 25 a of the lift variable member 18 to the control cams. 20 and 20 are biased toward the outer peripheral surface direction. That is, one torsion spring 23 biases both the swing cams 8 and 8 and the lift variable member 18 in opposite directions.

  The electric actuator 21 includes an electric motor 21a and a speed reducer (not shown). The control shaft 19 is controlled to rotate in the forward and reverse directions according to the engine operating state and is held at a predetermined rotational position. The electric motor 21 a is rotationally controlled by the electronic controller 22.

  The electronic controller 22 receives information signals from various sensors such as a crank angle sensor, a throttle opening sensor, a water temperature sensor, an air flow meter, etc., and detects the current engine operating state by calculation or the like. The current output to the electric motor 21a is controlled via the.

  In this embodiment, as shown in FIG. 4, when the drive cams 5a are in a predetermined rotation angle range and the lift variable member 18 is swung in a swingable angle range, The rotation center X of the roller 16, the axial center point Y of the pivot 17 of the swing cam 8, and the contact point Z between the swing cam 8 and the second roller 15 of the swing arm 6 are arranged substantially linearly. It is configured. Specifically, it will be described during the operation of the following apparatus.

  Hereinafter, the operation of the present embodiment will be described. First, the opening / closing operation of the intake valves 3 and 3 will be described. The rotational force transmitted from the crankshaft (not shown) to the camshaft 5 is transmitted to each drive cam 5a, and each drive cam 5a rotates eccentrically. Then, such eccentric rotation is transmitted to each of the rollers 16 and 16, and the swing cams 8 and 8 swing around the pivot 17 to convert to reciprocating motion.

  As a result, the cam surface 8c of the cam portion 8a, that is, the lift surface and the base circle surface move on the roller 15. Accordingly, each swing arm 6 is pressed downward against the spring force of the valve spring 12 and opens and closes each intake valve 3 while swinging and moving with the plunger 7c of the hydraulic lash adjuster 7 as a pivot point.

  Next, the operation of the device by the variable lift mechanism 9 will be described. First, in the low-rotation low-load operation region such as during idling operation of the engine, the electric actuator 21 is rotationally driven by the electronic controller 22 that detects this operation state. The control shaft 19 is controlled to a predetermined rotational position. As a result, as shown in FIGS. 1 and 5, the control cam 20 has a shaft center P1 that rotates and moves to a rightward position in the figure from the shaft center P of the control shaft 19. The part is rotated and held at the right position.

  Therefore, the lift variable member 18 is slightly rotated counterclockwise as shown in FIGS. 1 and 5 through the support shafts 26 and 26 when the distal end surface 25a is pressed by the thin portion of the control cam 20.

  For this reason, the swing cam 8 moves slightly in the direction in which the base portion 8a is separated from the camshaft 5 because the position of the pivot 17 is slightly rotated counterclockwise as shown in the figure. As a result, the contact position of the cam surface 8c of the cam portion 8b with the roller 15 moves from the approximate center of the cam surface 8c toward the base circle surface.

  Therefore, the intake valves 3 and 3 that are opened and closed by the swinging motion of the swing cams 8 accompanying the rotation of the drive cams 5a are controlled to be small as shown by the broken lines in FIG. . As a result, fuel consumption can be improved and engine rotation can be stabilized.

  On the other hand, for example, when shifting to the engine high rotation / high load region, the electric actuator 21 is rotationally driven by the electronic controller 22 that has detected this operation state, and the control shaft 19 is rotated to the right, for example. As a result, as shown in FIG. 6, the control cam 20 has its axis P1 moved to the left position from the axis P2 of the control shaft 19, and the thick portion of the control cam 20 is rotated and held at the left position. Is done.

  Therefore, the lift variable member 18 is further rotated in the counterclockwise direction about each support shaft 26 via the distal end surface 25a by the control cam 20.

  For this reason, the swing cam 8 is held at a position close to the camshaft 5 as the pivot 17 serving as the swing fulcrum moves greatly counterclockwise as shown in the figure. As a result, the contact position of the cam surface 8c of the cam portion 8b with the roller 15 moves from the approximate center of the cam surface 8c toward the lift surface.

  Therefore, as shown by the solid line in FIG. 7, the lift amount of each of the intake valves 3 and 3 that are opened and closed by the swing motion of each swing cam 8 in accordance with the rotation of each drive cam 5a is largely controlled. . As a result, the engine output can be improved.

  Further, in this embodiment, when the lift amount of the intake valve 3 is variably controlled from the small lift to the large lift by the variable lift mechanism 9, the lift peak phase shows the characteristic as shown in FIG. Yes. That is, as shown in FIG. 4 described above, when each roller 16 is in contact with the base circle surface of each drive cam 5a and when the lift variable member 18 is swung within a swingable angular range. In the intermediate lift, the rotation center X of the roller 16, the axial center point Y of the pivot 17 of the swing cam 8, and the contact point Z between the swing cam 8 and the second roller 15 of the swing arm 6 are connected. The line (Q) is straight, and with a small lift it moves slightly to the right in the figure centering on Q and becomes a nearly straight line Q1, while with a large lift it moves slightly to the left in the figure centering on Q. As a result, a substantially straight line Q2 is obtained.

  Therefore, as shown in FIG. 7, the peak lift PL (phase) of the lift characteristic from the small lift to the large lift of the intake valves 3 and 3 moves to the retard side or the advance side as in the prior art. Without change, it is possible to sufficiently suppress the change in the peak lift PL particularly during a small lift. Therefore, it is possible to suppress a large change in the peak lift PL at the time of the large and small lift characteristics, and it is possible to suppress the difference in the lift characteristics of the left and right banks in such a V-type internal combustion engine regardless of the rotation direction of the drive cam 5a. By arranging the variable lift mechanism 9 symmetrically, the upper part of the internal combustion engine can be configured compactly.

  Further, since the roller 16 is in contact with the base circle surface of the drive cam 5a, that is, the state where each intake valve 3 is closed, the opening / closing timing of the intake valve 3 is the rotation of the camshaft 5. It is possible to prevent deviation as much as possible depending on the direction.

  In this embodiment, the two swing cams 8 and 8 can be simultaneously controlled by one lift variable member 18 and a simple structure can be achieved, so that the manufacturing cost can be reduced.

  Further, the single torsion spring 23 functions to both press and bias the variable lift member 18 against the control cam 20 and to press the biasing cams 8 and 8 of the swing cams 8 and 8 onto the drive cams 5a and 5a. Can be demonstrated.

  Therefore, reliable operation of the lift variable member 18 and the swing cams 8 and 8 can be ensured, and the manufacturing work is facilitated by reducing the number of parts.

  In addition, since the torsion spring 23 is disposed in the dead space between the pair of swing cams 8, the space can be effectively used.

  Further, since both sides of the variable lift member 18 are supported by the support shafts 26, 26, the proper posture of the variable lift member 18 can be stably maintained, and inadvertent tilting during operation can be prevented. .

  Further, since the variable lift member 18 is integrally formed by press molding, the cost can be reduced.

  Further, in this embodiment, the bearing 4 is constituted by the frame-like member 4a and the bracket 4b on the cylinder head 1, and the camshaft 5 and the control shaft 19 are supported by the bearing 4 so that each component is unitized. Since it can be assembled to the cylinder head 1 in such a state, the assembly work efficiency can be improved and the package can be delivered so that the transport work efficiency can be improved.

  Since the camshaft 5 and the control shaft 19 are arranged in parallel to the bearing 4 in the horizontal direction instead of the vertical direction, the height of the engine can be made sufficiently small.

  In addition, since the camshaft 5 and the control shaft 19 are arranged, it is not necessary to greatly change the existing structure of the cylinder head 1, so that an increase in cost can also be suppressed in this respect.

  In addition, the presence of the frame-like member 4a improves the rigidity of the upper end portion of the cylinder head 1 and can suppress vibrations.

  The present invention is not limited to the configuration of the above-described embodiment. For example, the variable lift mechanism 9 can be applied to the exhaust valve side, and can also be applied to both sides of the intake and exhaust valves. Is possible.

  The technical ideas other than the invention described in the claims, as grasped from the embodiment, will be described below.

  First, when the roller is in contact with the base circle of the drive cam and the lift variable member is controlled to an intermediate lift amount within a lift variable range, the rotation center of the roller and the swing center The center point of the shaft and the contact point between the swing cam and the valve drive member are substantially linear.

  According to this invention, since the base circle of the drive cam and the roller are in contact with each other, that is, the engine valve is closed, the opening / closing timing of the engine valve depends on the rotation direction of the camshaft as much as possible. It can be prevented from shifting.

  Further, when the drive cam is in a peak lift state and the lift variable member is controlled to an intermediate lift amount within a variable lift range, the center of the roller, the center point of the swinging central axis, The contact point between the swing cam and the valve drive member is configured to be substantially linear.

  According to the present invention, since the peak lift state of the drive cam is used as a reference, the peak lift when the engine valve is opened can be prevented from shifting as much as possible depending on the rotation direction of the camshaft.

  Furthermore, a pair of swing cams are supported on the swing center shaft supported by one lift variable member.

  According to the present invention, two swing cams can be controlled simultaneously by one lift variable member, and a simple structure can be achieved, so that the manufacturing cost can be reduced.

The actuator comprises a control shaft having a control cam that abuts a part of the lift variable member, and a control mechanism that controls the rotation of the control shaft according to the engine operating state,
The lift variable member is biased toward the control shaft by a biasing means.

  The biasing means is interposed between the swing cam and the lift variable member, and is characterized in that a biasing force is applied to the swing cam in a direction in which the roller contacts the drive cam.

  According to this invention, the function of both pressing of the variable lift member against the control cam and pressing of the roller of the swing cam against the drive cam can be exhibited by one biasing means.

  Therefore, reliable operation of the lift variable member and the swing cam can be ensured, and the manufacturing work is facilitated by reducing the number of parts.

  In addition, a pair of swing cams are supported on the swing center shaft supported by the one lift variable member, and the urging means is disposed between the pair of swing cams. It is said.

  In the present invention, since the urging means can be arranged in the dead space between the pair of swing cams, the space can be effectively used.

  The central shaft is supported by each support bracket provided on the cylinder head, and supports both sides of the variable lift member.

  According to the present invention, since both sides of the variable lift member are supported by the central shaft, the proper posture of the variable lift member can be stably maintained, and inadvertent tilt during operation can be prevented.

  The invention according to claim 1 is characterized in that the variable lift member is formed by press molding in a substantially U-shaped cross section.

  According to this invention, since the variable lift member is integrally formed by press molding, the cost can be reduced.

1 is a side view showing a cross section of an embodiment of a variable valve operating apparatus according to the present invention. It is a front view of the variable valve apparatus of this embodiment. It is a disassembled perspective view of the variable valve apparatus of this embodiment. It is operation | movement explanatory drawing in this embodiment. It is operation | movement explanatory drawing at the time of the minimum valve lift control of this embodiment. It is operation | movement explanatory drawing at the time of the maximum valve lift control of this embodiment. It is a lift characteristic figure of the intake valve of this embodiment.

Explanation of symbols

1 ... Cylinder head 3 ... Intake valve (engine valve)
DESCRIPTION OF SYMBOLS 4 ... Bearing 4a ... Frame-like member 4b ... Bracket 5 ... Cam shaft 5a ... Drive cam 6 ... Swing arm 8 ... Swing cam 8a ... Cam part 8c ... Cam surface 8b ... Arm part 9 ... Lift variable mechanism 17 ... Pivot (swing (Dynamic fulcrum)
DESCRIPTION OF SYMBOLS 18 ... Variable lift member 19 ... Control shaft 20 ... Control cam 21 ... Electric actuator 22 ... Controller 23 ... Torsion spring (biasing means)
26 ... support axis (center axis)

Claims (3)

A camshaft that is rotationally driven by a crankshaft and has a drive cam provided on the outer periphery;
A swing cam having a follower that contacts the drive cam and performing a swing motion with the swing center axis as a fulcrum;
A valve operating member that contacts the swing cam to open and close the engine valve;
A lift variable member that supports the swing center shaft and swings within a range of a predetermined angle around the center axis to change the position of the swing center shaft to variably control the lift amount of the engine valve. When,
An actuator for changing the lift variable member according to the operating state of the engine;
A variable valve operating apparatus for an internal combustion engine comprising:
A variable valve operating apparatus for an internal combustion engine, wherein a range of a rotation angle of the drive cam operates within a range in which the variable lift member includes at least an intermediate lift amount that is a lift amount near the center of the variable lift range. A camshaft that is rotationally driven by a crankshaft and has a drive cam provided on the outer periphery;
A swing cam having a follower that contacts the drive cam and performing a swing motion with the swing center axis as a fulcrum;
A valve operating member that contacts the swing cam to open and close the engine valve;
A lift variable member that variably controls the lift amount of the engine valve by changing the position of the swing center shaft by supporting the swing center shaft and swinging within a predetermined angle range about the center axis. When,
An actuator for changing the lift variable member according to the operating state of the engine;
A variable valve operating apparatus for an internal combustion engine comprising:
When the drive cam is in a predetermined rotation angle range and the lift variable member is swung in a swingable angle range, the center of curvature of the follower, and the center point of the swing center axis, A variable valve operating apparatus for an internal combustion engine, characterized in that contact points between the swing cam and the valve operating member are arranged substantially linearly. A camshaft that is rotationally driven by a crankshaft and has a drive cam provided on the outer periphery;
A swing cam having a first roller in contact with the drive cam and performing a swing motion about a swing center axis;
A swing arm that has a second roller against which the swing cam abuts, and that opens and closes the engine valve via the second roller in accordance with the swing motion of the swing cam;
A lift variable member that variably controls the lift amount of the engine valve by changing the position of the swing center shaft by supporting the swing center shaft and swinging within a predetermined angle range about the center axis. When,
An actuator for changing the lift variable member according to the operating state of the engine;
A variable valve operating apparatus for an internal combustion engine comprising:
When the drive cam is in a predetermined rotation angle range and the lift variable member is controlled to an intermediate lift amount in the lift variable range, the rotation center of the first roller and the center of the swing center axis A variable valve operating apparatus for an internal combustion engine, characterized in that the point and the rotation center of the second roller are arranged substantially in a straight line.

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