JP4986788B2 - Variable valve operating device for internal combustion engine - Google Patents

Description

  The present invention relates to an improvement in a variable valve gear that can variably control, for example, the valve lift amount and operating angle of an intake valve and an exhaust valve of an internal combustion engine according to the operating state of the engine.

  Various types of conventional variable valve operating apparatuses for internal combustion engines are provided. For example, one described in Patent Document 1 below is known.

  This variable valve operating device is provided with a drive cam fixed on the outer periphery and rotated by a rotational drive force from the crankshaft of the engine, and is provided for each cylinder of the engine and supported by the drive shaft so as to be relatively rotatable. A camshaft, a valve lifter that opens and closes an engine valve that is normally urged in a closing direction by a valve spring by moving up and down, and is provided integrally with each camshaft and swings through the valve lifter. A pair of swing cams for opening and closing the engine valve, one end side being biased to one side in the axial direction and linked to the drive cam via a link arm, and the other end side being connected to the drive cam via a link rod A rocker arm linked to one of the rocking cams of the cam, and a base provided between both ends of the rocker arm or linked to one end of the rocker arm. And a, and a control mechanism for changing the lift characteristics of the engine valve by changing the position of the rocker arm.

In this variable valve operating apparatus, the valve lifter is biased so that the thickness width center of the one rocking cam approaches the base of the rocker arm or one end of the rocker arm with respect to the shaft center of the valve lifter. , And the occurrence of uneven wear on the upper surface of the valve lifter can be suppressed.
JP 2000-230409 A

  However, in the conventional variable valve system for an internal combustion engine, the thickness width center of the one swing cam is biased so as to approach one end side of the rocker arm with respect to the shaft center of the valve lifter. Yes. As a result, one end side of the rocker arm is largely biased toward the drive cam side so as to be separated from the axis of the base portion of the rocker arm, while the other end side of the rocker arm is arranged near the axial center of the base portion of the rocker arm. Thus, the one end side and the other end side of the rocker arm are unbalanced with respect to the base portion.

  For this reason, during operation, the driving force transmitted from the drive cam to the one end side of the rocker arm, the reaction force of the valve spring transmitted from the valve lifter to the other end side of the rocker arm via the swing cam and the link arm, etc. The rocker arm will fall and a so-called rocker arm will fall (tilt). As a result, an offset load is applied to the connecting portion between the rocker arm and the control mechanism and the connecting portion between the rocker arm, the link arm, and the link rod, and there is a possibility that seizure occurs at each connecting portion.

  The present invention has been devised by paying attention to such a technical problem, and is an enabling of an internal combustion engine that can suppress the tilting of the rocker arm during the operation of the apparatus and can realize a smooth operation of the connecting portion with the rocker arm. A variable valve device is provided.

The present invention provides a drive shaft to which rotational driving force is transmitted from a crankshaft, a drive cam fixed to the outer periphery of the drive shaft, and is provided for each cylinder of the engine so as to be relatively rotatable on a predetermined support shaft. Camshafts, a valve lifter that opens and closes an engine valve that is normally biased in the closing direction by a biasing force of a valve spring by moving up and down, and is provided integrally with each camshaft and swings to A pair of swing cams for opening and closing the engine valve via a valve lifter, a rocker arm whose one end is linked to the drive cam via a link arm, the other end of the rocker arm and the pair of swing cams An engine valve is configured by changing the posture of the rocker arm in association with a link rod that links one swing cam and a base provided between both ends of the rocker arm. And a control mechanism for changing the lift characteristic, a,
A variable valve operating apparatus for an internal combustion engine, wherein one end side and the other end side of the rocker arm are offset from each other in the axial direction with respect to a base portion of the rocker arm, the thickness of the one rocking cam being The center in the width direction and the center in the width direction of the link rod are substantially coincided with each other, and the center in the thickness width direction of the one swing cam and the center in the thickness width direction of the link rod are It is characterized in that it is biased by a predetermined amount in the direction away from the link arm with respect to the axial center of the valve lifter with which it contacts .

According to this invention, the center in the thickness width direction of one swing cam and the thickness width center of the link arm are separated from the link arm with respect to the axial center of the valve lifter with which the one swing cam abuts. When the rocker arm is biased by a predetermined amount, the moment caused by the force received by the one end of the rocker arm from the drive cam side and the moment caused by the force received by the other end of the rocker arm from the rocking cam side cancel each other out. The moment acting on the rocker arm can be balanced. Thereby, the so-called falling phenomenon of the rocker arm as in the prior art is suppressed, and smooth operation of the rocker arm and the portion linked thereto can be realized.

  In addition, in this case, one of the swing cams comes into contact with the valve lifter at a position deviated with respect to the shaft center of the valve lifter, so that the rotation of the valve lifter can be promoted. It is also possible to prevent uneven wear on the contact surface with the swing cam.

  Hereinafter, embodiments of a variable valve operating apparatus for an internal combustion engine according to the present invention will be described in detail with reference to the drawings. In each embodiment, such a device is applied to the intake side of a V-type six-cylinder internal combustion engine, and the drawing of this embodiment shows a case where it is applied to one side of three cylinders.

  That is, as shown in FIGS. 1 and 2, this variable valve operating device is slidably provided on the cylinder head 1 via a valve guide (not shown) and is urged in the closing direction by the valve springs 3 and 3. A pair of first and second intake valves 2a and 2b provided per cylinder, a variable mechanism 4 for variably controlling the lift amount of each intake valve 2a and 2b, and an operating position of the variable mechanism 4 And a drive mechanism 6 that rotationally drives the control mechanism 5.

  The variable mechanism 4 includes a hollow drive shaft 13 rotatably supported by a bearing 14 provided at the upper end portion of the cylinder head 1, and one drive cam per cylinder fixed to the drive shaft 13 by press fitting or the like. 15 and is slidably contacted with the upper surfaces of the first and second valve lifters 16a and 16b, which are swingably supported on the outer peripheral surface of the drive shaft 13 and disposed at the upper ends of the intake valves 2a and 2b. The swing cam constituting body 17 for opening the intake valves 2a and 2b, respectively, and the swing cam constituting body 17 and the drive cam 15 are linked to each other. And one transmission means per cylinder for transmitting as a swinging force of the cylinder.

  The drive shaft 13 is arranged along the longitudinal direction of the engine, and a rotational driving force is transmitted from the crankshaft of the engine via a timing chain wound around a driven sprocket 7 provided at one end. The direction of rotation is set in the direction of the arrow in FIG.

  The bearing 14 is mounted on the upper surface of the bearing base 1a integrally provided at the upper end portion of the cylinder head 1 and rotatably supports the drive shaft 13 via a cam shaft 18 described later. The bracket 14a is fastened together from above by a pair of bolts 14b and 14b.

  As shown in FIGS. 6 and 7, the drive cam 15 is formed in a substantially ring shape, and includes an annular cam body and a cylindrical portion integrally provided on the outer end surface of the cam body. A drive shaft insertion hole is formed through the inner shaft direction, and the shaft center Y of the cam body is offset from the shaft center X of the drive shaft 13 by a predetermined amount in the radial direction. The drive cam 15 is fixed to the drive shaft 13 through a drive shaft insertion hole at a position where it does not interfere with the valve lifters 16a and 16b, and the outer peripheral surface of the cam body has an eccentric circular cam profile. Is formed.

  As shown in FIGS. 1, 3, and 4, the rocking cam structure 17 includes a cylindrical camshaft 18 that is rotatably fitted on an outer peripheral surface of the drive shaft 13 as a support shaft, The camshaft 18 includes a pair of first and second rocking cams 19 a and 19 b that are integrally disposed at both ends in the axial direction at a predetermined interval, and is driven entirely through the camshaft 18. The shaft 13 is swingably supported.

  The camshaft 18 has an insertion hole through which the drive shaft 13 is inserted, and a journal portion rotatably supported by the bearing 14 at a substantially intermediate position between the swing cams 19a and 19b. 18a is integrally formed.

  The two swing cams 19a and 19b are formed in substantially the same shape as raindrops, have cam nose portions 21a and 21b extending to the front end side, and cam surfaces which are in sliding contact with the corresponding valve lifters 16a and 16b on the lower surfaces. 22a and 22b are formed. The cam surfaces 22a and 22b are provided on a base circle surface on the camshaft 18 side, a ramp surface extending in an arc from the base circle surface to the cam nose portion 21 side, and provided on the distal end side of the cam nose portion 21 from the ramp surface. Lift surfaces that are continuous with the top surfaces of the maximum lifts formed so as to contact the upper surfaces of the corresponding valve lifters 16a and 16b according to the swing positions of the swing cams 19a and 19b. It has become.

  Of the swing cams 19a and 19b, the cam nose portion 21a side of the first swing cam 19a directly linked to the drive cam 15 via the transmission means has a link rod 25 described later. A pin hole through which a pin 28 for connecting to the other end 25b is inserted is formed.

  The transmission means includes a rocker arm 23 arranged one above each of the cylinders above the drive shaft 13, a link arm 24 linking the one end 23 a of the rocker arm 23 and the drive cam 15, and the rocker arm 23. A link rod 25 that links the other end 23b and the first swing cam 19a.

  The rocker arm 23 has a substantially cylindrical base portion 23c at the center, and the base portion 23c is rotatably supported by a control cam 33 described later via a support hole which is an inner peripheral portion thereof. Further, as shown in FIG. 5, the one end portion 23a and the other end portion 23b of the rocker arm 23 are provided to be offset in directions opposite to each other at each end portion in the axial direction of the base portion 23c.

As shown in FIGS. 1 and 3 to 5, the one end portion 23 a of the rocker arm 23 protrudes radially outward at one axial end portion of the base portion 23 c and is outside the one axial end of the base portion 23 c. Write have been extended along the axial direction so as to protrude, on its outer side, the pin 26 connecting the projecting ends 24b of the link arm 24 to be described later with the one end portion 23a is protruded.

  On the other hand, the other end portion 23b of the rocker arm 23 protrudes along the radial direction substantially opposite to the one end portion 23a at the other end portion in the axial direction of the base portion 23c, and is axially different from the one end portion 23a. On the opposite side, it extends so as to protrude outward from the other axial end of the base 23c, and on its inner peripheral side, there is a pin hole into which a pin 27 connected to one end 25a of the link rod 25 is fitted. Is formed.

3 and 4, the rocker arm 23 has a first swing cam 19 a linked to the other end 23 b toward the second valve lifter 16 b adjacent to the bearing 14. That is, the first valve lifter 16a is brought into contact with the base portion 23c while being slightly biased in the axial center Z of the base portion 23c or in a direction away from the one end portion 23a. Specifically, the thickness width direction center Xa of the first swing cam 19a is located along the width direction of the first swing cam 19a from the radial center (axial center) Ca on the upper surface of the first valve lifter 16a. consists axial center Z of the base 23c by quantitative L1, a state that is the misaligned in a direction away from the link arm 24. The thickness-width direction center Xb of the second rocking cam 19b also has a positional deviation between the thickness-width direction center Xa of the first rocking cam 19a and the shaft center Ca of the first valve lifter 16a. , a state from the axial center Z, i.e. the misaligned in a direction away from the link arm 24 of the second on the upper surface of the valve lifter 16b along the width direction of the second swing cam 19b by a predetermined amount L2 the base 23c It has become.

  As shown in FIGS. 6 and 7, 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 into which the cam body of the drive cam 15 is rotatably fitted is formed at the center position of the base 24a, while the pin 26 is rotatably inserted into the protruding end 24b. A hole is formed through.

  The link rod 25 is formed in a substantially square shape having a concave shape on the rocker arm 23 side, and is inserted into each pin hole of the other end portion 23b of the rocker arm 23 and the cam nose portion 21 of the swing cam 17 at both end portions 25a and 25b. Pin insertion holes through which end portions of the respective pins 27 and 28 are rotatably inserted are formed.

  At one end of each of the pins 26, 27, 28, a so-called snap ring is provided to restrict the axial movement of the link arm 24 or the link rod 25, or the pin 27 is locked as shown in FIG. The movement of the pins 27 and 28 in the axial direction is restricted by fixing them with bolts or providing pins 28 with flanges.

  As shown in FIGS. 1 to 3, the control mechanism 5 is provided integrally with a control shaft 32 rotatably supported by the same bearing 14 above the drive shaft 13 and an outer peripheral surface of the control shaft 32. And a control cam 33 serving as a rocking fulcrum of the rocker arm 23.

  The control cam 33 is provided for each cylinder, that is, for each rocker arm 23. As shown in FIGS. 6 and 7, the control cam 33 is formed in a substantially eccentric ring shape, and the position of the axis P2 is the position of the control shaft 32. It is deviated from the axis P1 by a predetermined amount.

  As shown in FIG. 1, the drive mechanism 6 is provided in a housing (not shown) fixed to the rear end of the cylinder head 1, an electric motor 35 fixed to one end of the housing, and the housing. And a ball screw transmission mechanism 36 that transmits the rotational driving force of the electric motor 35 to the control shaft 32.

  The electric motor 35 is constituted by a proportional DC motor, and is fixed in a state in which a rectangular tip portion of a substantially cylindrical motor casing 37 seals one end opening of the housing. Further, as shown in FIG. 1, the electric motor 35 is driven by a control signal from a control unit 38 that detects the driving state of the engine.

  The control unit 38 feeds back detection signals from various sensors such as a crank angle sensor 39, an air flow meter 40, a water temperature sensor 41, and a potentiometer 42 for detecting the rotational position of the control shaft 32 to feed the current engine operating state. Is detected by calculation or the like, and a control current is output to the electric motor 35.

  The ball screw transmission mechanism 37 includes a ball screw shaft 43 disposed coaxially with a drive shaft of the electric motor 35 in the housing, a ball nut 44 screwed onto the outer periphery of the ball screw shaft 43, and the control shaft. 32, and a link member 46 that links the linkage arm 45 and the ball nut 44. The ball nut 44 is connected to each ball via each ball. By converting the rotational motion of the ball screw shaft 43 into the linear motion of the ball nut 46, an axial movement force is applied.

  Hereinafter, the control action of the valve lift amount of each intake valve 2a, 2b by each variable mechanism 4 of the variable valve operating apparatus for an internal combustion engine according to the present embodiment will be described in detail with reference to FIGS.

  First, for example, in the low-rotation operation region including the idling operation of the engine, when the electric motor 35 is rotated by the control current from the control unit 38, the ball screw shaft 43 is rotated by the rotation torque. The ball nuts 44 are linearly moved in one direction while the balls roll between the ball circulation grooves and the guide grooves.

  Then, as shown in FIG. 6, the control shaft 32 is rotationally driven clockwise by the link member 46 and the linkage arm 45, and the control cam 33 is driven by the axis P2 as shown in FIGS. 6A and 6B. Rotates around the axis P1 of the control shaft 32 with the same radius, and the thick portion moves away from the drive shaft 13 upward.

  As a result, the other end 23 b of the rocker arm 23 and the pivot point of the link rod 25 move upward with respect to the drive shaft 13, and the swing cams 19 a and 19 b are connected to the cam noses via the link rod 25. The parts 21a and 21b are forcibly pulled up, and the whole is rotated clockwise.

  Therefore, when the drive cam 15 rotates and pushes up the one end portion 23a of the rocker arm 23 via the link arm 24, the valve lift amount is changed from the swing cams 19a, 19b to the valve lifters 16a via the link rod 25. , 16b, the valve lift is sufficiently small.

  Accordingly, in the low rotation region of such an engine, the valve lift amount becomes the smallest as shown by L1 in FIG. 8, so that the opening timing of each intake valve 2a, 2b is delayed, and the valve overlap with the exhaust valve occurs. Get smaller. For this reason, improvement in fuel consumption and stable rotation of the engine can be obtained.

  When the engine is shifted to the high engine speed range, the electric motor 36 is rotated in reverse by the control current output from the control unit 38, and this rotation torque is transmitted to the ball screw shaft 43 to rotate. Accordingly, the ball nut 44 linearly moves in the other direction via each ball.

  Then, the control shaft 32 rotates the control cam 33 clockwise from the position shown in FIG. 6 to rotate the shaft center P2 downward as shown in FIGS. 7A and 7B. As a result, the entire rocker arm 23 is moved toward the drive shaft 13 and the other end 23b presses the cam nose 21a of the first rocking cam 19a downward via the link rod 25. The entire cams 19a, 19b are rotated counterclockwise by a predetermined amount.

  For this reason, when the drive cam 15 rotates and pushes up the one end portion 23a of the rocker arm 23 via the link arm 24, the valve lift amount is changed from the swing cams 19a, 19b to the valve lifters 16a, The amount of valve lift is increased.

  Therefore, in such a high rotation region, the valve lift amount of each intake valve 2a, 2b is maximized as shown by L2 in FIG. 8, so that the opening timing of each intake valve 2a, 2b becomes earlier and the closing timing becomes higher. Becomes slower. As a result, the intake charging efficiency is improved and a sufficient output can be secured.

  According to this embodiment, during operation of the apparatus, the rotational driving force of the drive cam 15 is input to the one end portion 23a of the rocker arm 23 via the link arm 24 as shown in FIG. On the other hand, the reaction force of each valve lifter 16a, 16b (force that urges each intake valve 2a, 2b in the closing direction) is input to the other end 23b of the rocker arm 23 via the link rod 25. However, as shown in FIGS. 3, 4, and 9, the center Xa of the first swing cam 19a in the thickness width direction is set to the axial center Ca of the first valve lifter 16a with which the swing cam 19a abuts. On the other hand, by being biased away from the base 23c of the rocker arm 23, from the point where the force F1 received by the one end 23a of the rocker arm 23 from the drive cam 15 side acts to the axis Z of the base 23c. And the distance, and the other end portion 23b of the rocker arm can be reduced and the distance from the point of action of the force F2 applied from the first swing cam 19a side to the axis Z of the base 23c, the differences.

  Thereby, in the rocker arm 23, the moment M1 (clockwise arrow in FIGS. 3 and 9) due to the force F1 received by the one end 23a of the rocker arm 23 from the drive cam 15 side and the other end 23b of the rocker arm are the first. 1 The moment M2 (counterclockwise arrow in FIGS. 3 and 9) due to the force F2 received from the swing cam 19a side can be balanced, and the tilting moment of the entire rocker arm 23 is reduced. .

  Therefore, according to this embodiment, a so-called falling phenomenon of the so-called rocker arm 23 as in the prior art is suppressed, and smooth operation of the rocker arm 23 and the portion linked thereto can be realized.

  In addition, in this case, as shown in FIGS. 3 and 4, the first swing cam 19a is in contact with the valve lifter 16a at a position deviated from the axial center Ca of the first valve lifter 16a. Therefore, the rotation of the first valve lifter 16a can be promoted, and uneven wear of the contact surface of the valve lifter 16a with the first swing cam 19a can be prevented.

  In addition, the second swing cam 19b is also arranged so as to be deviated in a direction away from the base 23c of the rocker arm with respect to the shaft center Cb of the second valve lifter 16b, so that the second swing cam 19b The same effect as the effect of suppressing the uneven wear on the first swing cam 19a side can be obtained between the second valve lifter 16b and the axial length of the camshaft 18, that is, the journal portion. The axial length of 18a can be provided longer, and as a result, a wide sliding width of the camshaft 18 can be ensured. Thereby, the wear resistance and seizure resistance of the outer peripheral surface of the journal portion 18a due to friction with the bearing 14 can be improved, and the falling behavior of the camshaft 18 can be reduced, so that the rocker arm can be more reliably tilted. Can be suppressed.

10 to 12 show a second embodiment of the variable valve operating apparatus for an internal combustion engine according to the present invention, in which the relative position between the second swing cam 19b and the second valve lifter 16b in the first embodiment is shown. Specifically, as shown in FIGS. 10 and 11, the second rocking cam 19b is arranged such that its thickness width direction center Xb is set to the shaft center Cb of the second valve lifter 16b. On the other hand, it is arranged so as to be biased in a direction close to the base 23c side (link arm 24 side) of the rocker arm by the predetermined amount L2.

  Furthermore, in this embodiment, as shown in FIG. 12, the axial length of the base portion 23c of the rocker arm 23 is extended, that is, the other axial end portion of the base portion 23c extends further outward in the axial direction. The other end surface E in the axial direction of the base portion 23c and the other end surface in the axial direction of the other end portion 23b without changing the relative positional relationship between the both end portions 23a and 23b with respect to the axial center of the base portion 23c. e constitutes the same plane.

  Therefore, according to this embodiment, the same effect as that of the first embodiment can be obtained, and the second swing cam 19b is biased in the direction close to the base 23c of the rocker arm. By being constituted, it is used for shortening of the axial direction length of the camshaft 18, thereby achieving downsizing of the apparatus.

  In addition, in the rocker arm 23, the other axial end of the base 23c is extended so that the other axial end E of the base 23c and the other axial end e of the other end 23b constitute the same plane. As a result, both end faces E and e can be processed simultaneously, so that the workability of the rocker arm 23 can be improved and the manufacturing cost of the apparatus can be reduced.

  The present invention is not limited to the configuration of each of the embodiments described above, and the present apparatus can be applied not only to the intake valves 2a and 2b but also to the exhaust valve.

  In each of the above embodiments, the drive shaft 13 is also used as the support shaft of the camshaft 18. However, the support shaft of the camshaft 18 may be provided separately from the drive shaft 13.

  In each of the above embodiments, the drive cam 15 having the eccentric circular cam profile is employed. However, the cam profile of the drive cam 15 may be configured to push up the one end portion 23a of the rocker arm 23.

1 is a perspective view showing an entire variable valve operating apparatus for an internal combustion engine according to the present invention. It is a front view of FIG. FIG. 3 is a main part enlarged view of FIG. 2 showing the first embodiment of the present invention and showing the features of the embodiment. It is the figure which looked at the transmission mechanism from the lower part in FIG. It is a top view which shows the rocker arm single-piece | unit of the 1st Embodiment of this invention. 1A is a view as viewed in the direction of the arrow A in FIG. 1 showing the valve closing action during the minimum lift control in the variable valve operating apparatus, and B is a view taken in the direction of the arrow A in FIG. 1A is a view as viewed from an arrow A in FIG. 1 showing a valve closing action at the time of maximum lift control in the variable valve operating apparatus, and B is a view as seen from an arrow A of FIG. It is a valve lift characteristic view of each intake valve by the variable valve operating apparatus of the present embodiment. It is an expansion perspective view of the transmission mechanism explaining the characteristic effect of the 1st Embodiment of this invention. FIG. 3 is an enlarged view of a main part of FIG. 2 showing a second embodiment of the present invention and showing features of the embodiment. It is the figure which looked at the transmission mechanism from the lower part in FIG. It is a top view which shows the rocker arm single-piece | unit which concerns on the 2nd Embodiment of this invention.

Explanation of symbols

2a ... 1st intake valve (engine valve)
2b ... Second intake valve (engine valve)
DESCRIPTION OF SYMBOLS 3 ... Valve spring 5 ... Control mechanism 13 ... Drive shaft 15 ... Drive cam 16a ... 1st valve lifter (valve lifter)
16b ... 2nd valve lifter (valve lifter)
18: Camshaft 19a: First swing cam (one swing cam)
19b ... 2nd rocking cam (the other rocking cam)
23 ... Rocker arm 23a ... One end (one end of the rocker arm)
23b ... the other end (the other end of the rocker arm)
23c ... Base (Rocker arm base)
Xa: thickness width direction center of the first rocking cam (thickness width direction center of one rocking cam)
Xb: thickness-width direction center of the second rocking cam (thickness-width direction center of the other rocking cam)
Ca: shaft center of the first valve lifter (shaft center of the valve lifter with which the first swing cam abuts)
Ca: shaft center of the second valve lifter (shaft center of the valve lifter with which the second swing cam abuts)

Claims (3)

A drive shaft to which rotational driving force is transmitted from the crankshaft;
A drive cam fixed to the outer periphery of the drive shaft;
A camshaft provided for each cylinder of the engine and supported by a predetermined support shaft so as to be relatively rotatable;
A valve lifter that opens and closes an engine valve that is normally urged in the closing direction by the urging force of the valve spring by moving up and down;
A pair of swing cams provided integrally with each camshaft and swinging to open and close the engine valve via the valve lifter;
A rocker arm whose one end is linked to the drive cam via a link arm ;
A link rod that links the other end of the rocker arm and one of the pair of swing cams;
A control mechanism that changes the lift characteristics of the engine valve by changing the posture of the rocker arm in association with a base portion provided between both ends of the rocker arm;
A variable valve operating apparatus for an internal combustion engine, wherein one end side and the other end side of the rocker arm are offset from each other in the axial direction with respect to a base portion of the rocker arm,
While the thickness width direction center of the one rocking cam and the thickness width direction center of the link rod are substantially matched,
A direction in which the center of the width direction of the one swing cam and the center of the link rod in the width direction are separated from the link arm with respect to the axial center of the valve lifter with which the one swing cam abuts. A variable valve operating apparatus for an internal combustion engine, characterized by being biased by a predetermined amount . A drive shaft to which rotational driving force is transmitted from the crankshaft;
A drive cam fixed to the outer periphery of the drive shaft;
A camshaft provided for each cylinder of the engine and supported by a predetermined support shaft so as to be relatively rotatable;
A valve lifter that opens and closes an engine valve that is normally urged in the closing direction by the urging force of the valve spring by moving up and down;
A pair of swing cams provided integrally with each camshaft and swinging to open and close the engine valve via the valve lifter;
A rocker arm whose one end is linked to the drive cam via a link arm;
A link rod that links the other end of the rocker arm and one of the pair of swing cams;
A control mechanism that changes the lift characteristics of the engine valve by changing the posture of the rocker arm in association with a base portion provided between both ends of the rocker arm;
A variable valve operating apparatus for an internal combustion engine, wherein one end side and the other end side of the rocker arm are offset from each other in the axial direction with respect to a base portion of the rocker arm,
While the thickness width direction center of the one rocking cam and the thickness width direction center of the link rod are substantially matched,
The center of the one rocking cam in the thickness width direction and the center of the link rod in the thickness width direction are separated from the link arm with respect to the shaft center of the valve lifter with which the one rocking cam abuts. While biasing by a certain amount ,
The center in the thickness width direction of the other swing cam is biased by a predetermined amount in the direction away from the link arm with respect to the shaft center of the valve lifter with which the other swing cam abuts. A variable valve operating device for an internal combustion engine. A drive shaft to which rotational driving force is transmitted from the crankshaft;
A drive cam fixed to the outer periphery of the drive shaft;
A camshaft provided for each cylinder of the engine and supported by a predetermined support shaft so as to be relatively rotatable;
A valve lifter that opens and closes an engine valve that is normally urged in the closing direction by the urging force of the valve spring by moving up and down;
A pair of swing cams provided integrally with each camshaft and swinging to open and close the engine valve via the valve lifter;
A rocker arm whose one end is linked to the drive cam via a link arm;
A link rod that links the other end of the rocker arm and one of the pair of swing cams;
A control mechanism that changes the lift characteristics of the engine valve by changing the posture of the rocker arm in association with a base portion provided between both ends of the rocker arm;
A variable valve operating apparatus for an internal combustion engine, wherein one end side and the other end side of the rocker arm are offset from each other in the axial direction with respect to a base portion of the rocker arm,
While the thickness width direction center of the one rocking cam and the thickness width direction center of the link rod are substantially matched,
The center of the one rocking cam in the thickness width direction and the center of the link rod in the thickness width direction are separated from the link arm with respect to the shaft center of the valve lifter with which the one rocking cam abuts. While biasing by a certain amount ,
The center in the width direction of the other swing cam is deviated by a predetermined amount in the direction close to the link arm with respect to the shaft center of the valve lifter with which the other swing cam abuts. A variable valve operating device for an internal combustion engine.

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