JP5197399B2 - Variable valve operating device for internal combustion engine - Google Patents

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, which is an intake valve or an exhaust valve, according to an engine operating state.

  As a conventional variable valve operating apparatus for an internal combustion engine, one described in the following Patent Document 1 previously filed by the present applicant is known.

  This variable valve operating apparatus includes a drive shaft provided with a drive cam on the outer periphery, a pair of swing cams that open two intake valves per cylinder against the spring force of a valve spring, and the drive cam A transmission mechanism that converts a rotational force into a swing motion and transmits the swing motion to each swing cam; a control cam that is provided on a control shaft disposed in the longitudinal direction of the engine and changes a swing fulcrum of the transmission mechanism; It has.

  The drive shaft is rotatably supported on the cylinder head by a bearing member common to the control shaft, and a plurality of oscillating cams of a plurality of cylinders are provided on the outer periphery of the single drive shaft via the cylindrical members. And is supported rotatably.

  A swing arm is interposed between the swing cam and the intake valve. The swing arm is swingable to a hydraulic lash adjuster whose one end is held in the holding hole of the cylinder head. On the other hand, the other end is in contact with the stem end of the intake valve. Further, the swinging force of the swing cam is transmitted as the valve opening force of the intake valve while the cam surface of the swing cam is in rolling contact with the outer peripheral surface of the roller provided at the substantially central position of the swing arm. Yes.

  The hydraulic lash adjuster pushes up one end of the swing arm with the internal hydraulic pressure, so that the swing cam opens the intake valve, and of course, the swing cam is at the base circle of the swing cam. Even when the valve is closed, the roller clearance is adjusted to zero so that the roller and the swing cam are always in contact with each other.

  Then, the control cam is rotationally controlled by the actuator via the control shaft in accordance with the engine operation state, thereby changing the rocking fulcrum of the rocker arm, whereby the rocking cam moves the intake valve operating angle and lift amount. Is to change.

JP 2008-14322 A

  However, in the conventional variable valve device, a plurality of swing cams of a plurality of cylinders are rotatably supported on a common drive shaft, and one end of the swing arm is attached to the hydraulic lash adjuster. Since it is supported, when each intake valve of one cylinder is opened, the drive shaft may be slightly bent and deformed.

  That is, if each intake valve of one cylinder of a plurality of cylinders is pressed through a roller against the spring force of the valve spring to open (lift) the swing cam, the spring reaction force of this valve spring The drive shaft is bent and deformed. Then, the swing cams of the other cylinders in the base circle period (valve closing period) zero-adjusted by the hydraulic lash adjuster are slightly displaced downward to slightly open the intake valve. As a result, for example, during the idling operation, the air-fuel mixture in the combustion chamber may flow out of the minutely opened intake valves of the other cylinders, leading to engine rotation instability and fuel consumption reduction. In addition, there is a risk of power reduction during high-speed operation.

According to the first aspect of the present invention, in particular, each of the rocking cam components provided for each cylinder is integrally provided with a cylindrical member inserted into the outer periphery of the common shaft with a predetermined gap. The predetermined clearance is set to a size such that the outer peripheral surface does not contact the inner peripheral surface of the cylindrical member even when the common shaft is bent and deformed in the radial direction during engine operation. the outer peripheral surface of the cylindrical member, is characterized in that the rotatably supported respectively by at least two bearings provided in different axial positions of the cylindrical member.

  According to this invention, even if the spring reaction force of the valve spring is transmitted from the engine valve on the valve opening side to the common shaft and the common shaft is slightly bent and deformed, the bending deformation is absorbed by the gap. Since the cylindrical member of each rocking cam structure is supported in a two-point support state by a plurality of bearings, the displacement of the other rocking cam structure in the valve-closed state is suppressed. For this reason, transmission of the pressing force from the driven member to the engine valve in the valve closing state is avoided, and the valve closing state is maintained.

1 is a side view showing a partial cross section of a first embodiment in which a variable valve device according to the present invention is applied to one bank side of a V-type internal combustion engine. It is the sectional view on the AA line of FIG. It is a longitudinal cross-sectional view of the variable valve operating apparatus of 1st Embodiment. A and B are explanatory diagrams of operation at the time of controlling the minimum operating angle and the minimum valve lift amount of the present embodiment. A and B are explanatory drawings of the operation at the time of controlling the maximum operating angle and the maximum valve lift amount of the present embodiment. It is a valve lift characteristic view of this embodiment. It is a longitudinal cross-sectional view of the variable valve apparatus in 2nd Embodiment.

  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. In each of the embodiments, one applied to three cylinders on one bank side of a V-type six-cylinder internal combustion engine is shown.

[First Embodiment]
1 to 3 show a first embodiment of a variable valve operating apparatus, and two intake valves 3 and 3 per cylinder for opening and closing a pair of intake ports 2 and 2 formed in a cylinder head 1, and # A drive shaft 5 which is a common shaft having one drive cam 5a per cylinder on the outer periphery, arranged along the longitudinal direction of the engine above one cylinder, the # 3 cylinder and the # 5 cylinder, and the same as the drive shaft 5 A swing cam component 7 that is rotatably supported by a plurality of bearings and opens / closes each intake valve 3 via a swing arm 6 that is a driven member, and converts the rotational force of the drive cam 5a into a swing force. And a control mechanism 9 for controlling the operating angle and valve lift amount of each of the intake valves 3 and 3 via the transmission mechanism 8 and the cylinder head 1. Each intake valve 3 is held via each swing arm 6. A pair of hydraulic lash adjuster 10 for the valve clearance is always zero lash between the swing cam structure 7, and a.

Hereinafter, for convenience, each component in one cylinder, for example, the # 1 cylinder will be described in detail. Each intake valve 3 is slidably held by the cylinder head 1 via a valve guide 4, and each Each valve retainer 11 provided in the vicinity of the stem end 3a is urged in the closing direction by each valve spring 12 elastically contacted between the cylinder head 1 and the inner upper surface.

  The drive shaft 5 is rotatably supported by bearings 13 and 32 provided at the front and rear end portions of the cylinder head 1, and the rotational force of the crankshaft is transmitted through a timing pulley (not shown) provided at one end portion. Is to be transmitted by. Further, the drive cam 5a fixed to the outer periphery of the drive shaft 5 by the connecting pin 5b has an axis X that is eccentric from the axis Y of the drive shaft 5 in the radial direction, and the cam profile on the outer periphery is almost normal. It is formed in a circular shape.

  An oil hole 33 for supplying lubricating oil from an oil passage hole 32a formed in an end bearing 32 provided on the engine front side is formed in the internal shaft direction of the drive shaft 5. The lubricating oil that has flowed through the oil hole 33 is supplied to the first bearing 13 and the second bearing 34 described later via a plurality of oil holes 35 and 36.

  Each swing arm 6 is formed in the center while the lower surface of one end portion 6a is in contact with the stem end 3a of each intake valve 3 and the other end portion 6b is in contact with the hydraulic lash adjuster 10. The roller 14 is rotatably accommodated in the accommodating hole via the roller shaft 14a.

  As shown in FIG. 1 and the like, the both swing cam constituting bodies 7 are integrally provided at a cylindrical member 7a that is rotatably fitted on the outer peripheral surface of the drive shaft 5, and at both ends of the cylindrical member 7a. And two swing cams 7b and 7b corresponding to the two intake valves 3 and 3, respectively.

  Cam surfaces 7c and 7c each formed of a base circle surface, a ramp surface and a lift surface are formed on the lower surfaces of the swing cams 7b and 7b, respectively. The upper surface of the roller 14 of the swing arm 6 is brought into rolling contact according to the swing position of the moving cams 7b and 7b.

  The cylindrical member 7a is formed with a first journal portion 7d and a second journal portion 7e on each outer peripheral surface at one end side in the axial direction and at a substantially central position, and through the first and second journal portions 7d and 7e. The first bearing 13 and a second bearing 34 different from the first bearing 13 are rotatably supported by an oil film, and the inner peripheral surfaces of the bearings 13 and 34 The drive shaft 5 is rotatably supported with a radial gap T which is a minute clearance between the corresponding outer peripheral surfaces of the drive shaft 5. The radial gap T is set to a gap amount that does not allow direct contact between the outer peripheral surface of the drive shaft 5 and the inner peripheral surface of the cylindrical member 7a during operation of the internal combustion engine.

  The first bearing 13 includes a main bracket 13 a disposed at the upper end portion of the cylinder head 1 and a sub bracket 13 b disposed at the upper end portion of the main bracket 13 a, and has a semicircular arc shape on the cylinder head 1. The journal portion 7e of the cylindrical member 7a is rotatably supported between the bearing groove 1d and the semicircular bearing groove below the main bracket 13a. The main bracket 13a and the sub bracket 13b are fastened together on the cylinder head 1 by two bolts 13c. Further, a second oil passage hole 37 communicating with the oil hole 33 in the drive shaft 5 is formed inside the first bearing 13 on the engine front side, and the lubricating oil is supplied from here to the control shaft 21 side. It has become.

  The second bearing 34 includes a bearing bracket 34 a disposed at the upper end of the cylinder head 1. The second bearing 34 has a semicircular arc-shaped bearing groove 1 e on the cylinder head 1 and a semicircular arc shape formed below the bearing bracket 34 a. The journal part 7e of the cylindrical member 7a is rotatably supported between the bearing groove 34b. The bearing bracket 34a is fixed on the cylinder head 1 by two bolts 34c.

  The transmission mechanism 8 includes a rocker arm 15 disposed above the drive shaft 5, a link arm 16 that links the one end 15a of the rocker arm 15 and the drive cam 5a, and the other end 15b of the rocker arm 15. And a link rod 17 that links the moving cam 7.

  The rocker arm 15 has a cylindrical base portion at the center thereof rotatably supported by a control cam 22 described later via a support hole, and one end portion 15a is rotatably connected to the link arm 16 by a pin 18. On the other hand, the other end portion 15 b is rotatably connected to the upper end portion of the link rod 17 via a pin 19.

  In the link arm 16, the cam body of the drive cam 5a is rotatably fitted in a fitting hole 16a at the center position of an annular base portion, while the protruding end is connected to the rocker arm one end portion 15a by the pin 18. It is connected.

  The link rod 17 is rotatably connected to the cam nose portion side of one swing cam 7b through a pin 20 at the lower end portion.

  An adjusting mechanism 23 is provided between the other end 15b of the rocker arm 15 and the upper end of the link rod 17 to finely adjust the lift amount of each intake valve 3 when each component is assembled.

  The control mechanism 9 includes a control shaft 21 that is rotatably supported by another bearing groove of the same bearing member at a position above the drive shaft 5, and is fixed to the outer periphery of the control shaft 21, and is inserted into a support hole of the rocker arm 15. And a control cam 22 which is slidably inserted and serves as a rocking fulcrum of the rocker arm 15.

  The control shaft 21 is disposed in the longitudinal direction of the engine in parallel with the drive shaft 5 and is rotationally controlled by an actuator (not shown). An oil supply hole 38 that communicates with a second oil passage hole 37 formed in the first bearing 13 is formed in the direction of the internal axis of the control shaft 21. The oil passage hole 38 is provided between the upper end bearing groove of the first bearing 13 and the rocker arm 15 and the control cam 22 through a plurality of oil holes 39 and 40 formed in the control shaft 21 along the radial direction. Lubricating oil is supplied.

  On the other hand, the control cam 22 has a cylindrical shape, and the axial center position is deviated from the axial center of the control shaft 21 by a predetermined amount.

  The actuator (not shown) includes an electric motor fixed to one end of the housing, and a ball screw transmission means as a speed reduction mechanism that is provided inside the housing and transmits the rotational driving force of the electric motor to the control shaft 21. It is configured.

  The electric motor is constituted by a proportional DC motor and is driven by a control signal from a control unit (not shown) that detects the engine operating state.

  As shown schematically in FIG. 2, the hydraulic lash adjuster 10 includes a bottomed cylindrical body 24 held in a cylindrical holding hole 1 a of the cylinder head 1, and is accommodated in the body 24 so as to be slidable up and down. The reservoir 25 is formed in a lower portion of the body 24 through a partition hole formed in the lower portion of the body 24 and a plunger 25 constituting a reservoir chamber through an unillustrated partition wall integrally formed in the lower portion. A high pressure chamber communicating with the chamber, and a check valve provided inside the high pressure chamber and allowing the hydraulic oil in the reservoir chamber to flow only in the direction of the high pressure chamber. Further, a through hole 1b is formed inside the cylinder head 1 for discharging the hydraulic oil accumulated in the holding hole 1a to the outside.

  The body 24 is formed with a cylindrical first concave groove on the outer peripheral surface, and is formed on the peripheral wall of the first concave groove inside the cylinder head 1 with a downstream end at the first concave groove. A first passage hole that communicates the opened oil passage 30 and the inside of the body 24 is formed to penetrate in the radial direction.

  As shown in FIG. 2, the oil passage 30 communicates with a main oil gallery 31 for supplying lubricating oil formed in the cylinder head 1. Lubricating oil is pumped from the pump.

  When the pressure in the high pressure chamber becomes low as the plunger 25 advances, the hydraulic oil supplied from the oil passage 30 into the holding hole 1a is transferred from the first groove to the first passage hole, the second groove, and the second groove. The fluid flows into the reservoir chamber through the passage hole, and further pushes the check ball against the spring force of the first coil spring to flow the hydraulic oil into the high pressure chamber. As a result, the plunger 25 constantly pushes up the other end 6 b of the swing arm 6, and between the swing cams 7 b, 7 b and the one end 6 a of the swing arm 6 and the stem end 3 a of the intake valve 3 via the roller 14. The gap is adjusted to zero lash.

  Hereinafter, the basic operation of the variable valve operating apparatus according to the present embodiment will be described with reference to FIGS. 4 and 5.

  First, for example, in a low rotation range such as an idling operation of an engine, the electric motor is rotationally driven by a control current output from the control unit, and this rotational torque is transmitted to the control shaft 21 via a ball screw mechanism. When the control shaft 21 is driven to rotate in one direction, as shown in FIGS. 4A and 4B, the control cam 22 also rotates in one direction so that the shaft center rotates around the shaft center of the control shaft 21 with the same radius Then, the thick portion moves away from the drive shaft 5 in the upper right direction as illustrated. As a result, the other end portion 15b of the rocker arm 15 and the pivot point (the connecting pin 19) of the link rod 17 move upward with respect to the drive shaft 5, so that the swing cam structure 7 is connected to the link rod 17 The cam nose side is forcibly pulled up via

  Therefore, when the drive cam 5a rotates and pushes up the one end portion 15a of the rocker arm 15 via the link arm 16, the lift amount is transmitted to the swing cams 7b and 7b and the swing arms 6 via the link rod 17. Each intake valve 3 opens against the spring reaction force of the valve spring 12, and its lift amount L becomes sufficiently small as shown in FIG.

  For example, when the engine shifts to a high rotation region, when the electric motor reversely rotates by the control current from the control unit and rotates the ball screw mechanism in the same direction, the rotation is performed as shown in FIGS. 5A and 5B. Along with this, the control shaft 21 rotates the control cam 22 in the other direction, and the shaft center moves in the direction of the drive shaft 5.

  For this reason, the entire rocker arm 15 is moved in the direction of the drive shaft 5 and the cam nose portion of the swing cam constituting body 7 is pressed downward via the link rod 17 by the other end portion 15b. The entire cams 7b and 7b are rotated counterclockwise from the position shown in FIG. 4 by a predetermined amount. Therefore, as shown in FIG. 5B, the contact position of the cam surface 7b with respect to the outer peripheral surface of the roller 14 of each swing arm 6 of each swing cam 7 moves to the cam nose portion side (lift portion side).

  For this reason, when the drive cam 5a rotates and the one end 15a of the rocker arm 15 is pushed up through the link arm 16 when the intake valve 3 is opened, the swing cams 7b and 7b are moved through the swing arms 6 respectively. The intake valve 3 is opened against the spring force of each valve spring 12, and the valve lift increases while continuously changing as indicated by L1 in FIG.

  As described above, when the intake valves 3 of the # 1 cylinder shown in FIGS. 3 and 5B are opened, for example, in the high rotation region, the pressing force from the drive cam 5a causes the link arm 16 to pass through. Thus, the one end 15a of the rocker arm 15 is pushed up and the other end 15b is pushed down to push down the cam nose of each swing cam 7. Then, when the rollers 14 of the swing arms 6 are pushed down by the lift portions of the cam surfaces 7c of the swing cams 7 to open the intake valves 3, the large spring reaction forces FC1 and FC2 of the valve springs 12 swing. The arm 6 acts as a push-down force F1 on the drive cam 5a via the swing cam constituting body 7, the link rod 17, the rocker arm 15 and the link arm 16.

  Therefore, the drive shaft 5 has a clearance T between the outer peripheral surface of the drive shaft 5 and the inner peripheral surface of the cylindrical member 7a, and a clearance between the outer peripheral surface of the cylindrical member 7a and the inner peripheral surface of the bearing 34. Is slightly bent and deformed downward (in the direction of the intake valve 3). At this time, the intake valves 3 of the # 3 cylinder adjacent to the # 1 cylinder are in the closed state, but due to the downward deformation of the drive shaft 5, the intake valves 3 of the adjacent # 3 cylinder are There is a possibility that the valve may be slightly opened downward via the swing cams 7b and the swing arms 6.

  However, in the present embodiment, the existence of a relatively large gap T between the drive shaft 5 and the cylindrical member 7a, and the swing cam constituting bodies 7 are the first and second journal portions 7d, 7d of the cylindrical member 7a. Since the shaft is supported at two points by the first and second bearings 13 and 34 via 7e, the displacement of each rocking cam 7b is sufficiently suppressed, and the base circle section (closed) of each rocking cam 7b is closed. It is possible to prevent the intake valves 3 of the # 3 cylinder and # 5 cylinder from opening slightly in the middle of the valve).

  That is, the operation will be specifically described with reference to FIG. 3 and the like. First, at the time of maximum valve lift control shown in FIGS. 5A and 5B, the intake valves 3 and 3 of the reference cylinder (# 3 cylinder) are closed. In the valve state, for example, the intake valves 3 and 3 on the front adjacent cylinder (# 1 cylinder) side are open (peak lift). A large load F1 is applied to the drive cam 5a on the adjacent cylinder side. As a result, the drive cam 5a is deformed downward (in the intake valve 3 direction) by ΔS, and accordingly, the portion of the drive shaft 5 on the reference cylinder side also has ΔS1, S2 at the front side swing cam position and the rear side swing cam position, respectively. Only deforms downward.

  However, since a relatively large radial gap T exists between the drive shaft 5 and the cylindrical member 7a (ΔS1, S2 <T), the valve is closed (contact between the base circle surface and the roller 14). It is possible to suppress the occurrence of slight valve opening via the swing arm 6 due to the respective base circle surfaces of the swing cams 7b, 7b being pushed down.

  That is, the cylindrical member 7a of the swing cam structure 7 is pivotally supported by the two bearings of the first bearing 13 and the second bearing 34, and is not directly supported by the drive shaft 5. This is because the deformation of the drive shaft 5 is not affected by the rocking cams 7b, 7b on the reference cylinder side.

  Assuming the case where the radial gap T does not exist or the gap T is small and the drive shaft 5 supports the swing cam component 7 as in the prior art. As a result, first, the drive cam 5a is deformed downward by ΔS, and accordingly, the portion of the drive shaft 5 on the reference cylinder side is also deformed downward by ΔS1 and 2, but is swung by the deformation amounts ΔS1 and S2. The base circle surface side of the cams 7b and 7b is pushed down, and the intake valves 3 and 3 in the closed state are slightly opened, and there is a possibility that normal operation as an internal combustion engine is hindered.

  However, since there is a sufficient gap T between the drive shaft 5 and the cylindrical member 7a as in this embodiment, even if the drive shaft 5 is deformed, the gap T absorbs the deformation amount. Furthermore, since the cylindrical member 7a is supported at two points by the two bearings 13 and 34, even if the drive shaft 5 is deformed, there is almost no influence on the swing cam constituting body 7, and the cylindrical member 7a Falling is also suppressed and smooth rotation is always secured. As a result, normal and stable operation of the internal combustion engine can be obtained. Such an effect can be obtained in the same way even during low lift control such as idling operation.

  In the present embodiment, the lubricating oil that has flowed into the oil hole 33 of the drive shaft 5 from the oil passage 33 passes through the oil holes 35 and 36, and the inner surface of each cylindrical member 7 a and the bearings 13 and 34. Between the control shaft 21 and the first bearing 13 through the oil holes 39 and 40 and between the control shaft 21 and the control cam. 22 is supplied between the outer peripheral surface of 22 and the inner peripheral surface of the support hole of the rocker arm 15 to effectively lubricate each sliding portion.

[Second Embodiment]
FIG. 7 shows a second embodiment of the present invention. The basic structure is substantially the same as that of the first embodiment, but the difference is that the cylindrical member 7a of the rocking cam structure 7 is on one end side. In addition to the first bearing 13 and the central second bearing 34, the other end side is also supported by the third bearing 41.

  That is, each drive cam 5a is not fixed to the drive shaft 5 by the connection pin 5b, but is fixed by shrink fitting or the like, and the cylindrical portion in which the drive cam 5a engages the connection pin 5b is abolished. Thus, the axial length is short. On the other hand, the cylindrical member 7a is formed to have a longer axial length along with the abolition of the cylindrical portion of the drive cam, and a third journal portion 7f is formed on the outer peripheral surface of the extended portion. .

  The third bearing 41 includes a semicircular bearing groove 1e formed at the upper end of the cylinder head 1 and a third bracket 41a having an arc bearing groove at the lower part.

  Therefore, according to this embodiment, since the rocking cam structure 7 is rotatably supported by the three bearings 13, 34, and 41, the support rigidity is improved. Is further suppressed. As a result, a smoother swinging motion of each swing cam 7a, 7a can be ensured.

  The present invention is not limited to the configuration of each of the above embodiments, and may be a shaft member other than the drive shaft 5 inserted into the cylindrical member 7a of the rocking cam structure 7 as a common shaft. In FIG. 13 described in Japanese Patent Laid-Open No. 2002-168105, a swing cam component is supported on the control shaft, and the common shaft is the control shaft.

  The control shaft described in this publication also receives a load at the moment of maximum opening (peak lift) of each intake valve by each swing cam, and the other cylinder side part of the control shaft is bent and deformed thereby, and the base circle section Although there is a possibility that the valve opens abnormally even though it is (valve closing section), if the configuration of the present invention is applied to this, the occurrence of abnormal valve opening of the swing cam on the other cylinder side is suppressed. It becomes possible.

  Further, for example, in the technique shown in Japanese Patent Application Laid-Open No. 2008-115746, each swing cam shown in FIG. 7 is pivotally supported by a rocker shaft that is a holding cylinder that holds a control shaft movable in the axial direction. In this case, the rocker shaft may bend and deform in the radial direction when the other adjacent cylinders are maximum opened, and the intake valve may be abnormally opened during the base circle of the reference cylinder.

  However, by applying the present invention, the abnormal valve opening can be avoided in principle.

  That is, if the two cylindrical portions on both sides in the axial direction of the cam nose portion 32d (34d) of the swing cam shown in FIG. 7 of the publication are supported, and two bearings for supporting these two cylindrical portions are provided. Good. Thereby, the occurrence of abnormal valve opening can be effectively suppressed.

  In addition to the intake valve 3, the engine valve can also be applied to the exhaust valve side. Further, the internal combustion engine can be applied not only to the V type 6 cylinder but also to an engine such as a V type 8 cylinder or an inline 4 cylinder.

  Further, the driven member is not limited to a swing arm, but may be a bucket-type tappet and may have a built-in hydraulic lash adjuster.

  Furthermore, in the second embodiment (FIG. 7), the drive shaft 5 can be directly supported by the third bearing 41 without extending the entire length of the cylindrical member 7a. In this case, the deflection of the entire drive shaft 5 and the deflection ΔS at the drive cam portion can be reduced, the operation can be further smoothed, and the abnormal valve opening is less likely to occur.

DESCRIPTION OF SYMBOLS 1 ... Cylinder head 1a ... Holding hole 3 ... Intake valve (engine valve)
5 ... Drive shaft 5a ... Drive cam 6 ... Swing arm (driven member)
DESCRIPTION OF SYMBOLS 7 ... Swing cam structure 7a ... Cylindrical member 7b ... Swing cam 7c ... Cam surface 7d * 7e ... 1st, 2nd journal part 8 ... Transmission mechanism 9 ... Control mechanism 10 ... Hydraulic lashia adjuster 12 ... Valve spring 13 ... 1st bearing part 13a ... Bearing bracket 14 ... Roller 34 ... 2nd bearing 34a ... Bearing bracket 41 ... 3rd bearing 41a ... Bearing bracket

Claims (2)

One rocking cam structure per cylinder for opening the engine valve via a driven member;
A hydraulic lash adjuster for adjusting the clearance between the driven member and the cam surface of the swing cam structure to zero;
A transmission mechanism for converting the rotational force of the drive cam into the swing force of the swing cam component;
With
A variable valve operating apparatus for an internal combustion engine that varies the valve lift amount of the engine valve by changing the attitude of the transmission mechanism according to an engine operating state,
Each rocking cam structure provided for each cylinder includes a cylindrical member fitted with a predetermined gap on the outer periphery of the common shaft, and a rocking cam provided integrally with the cylindrical member,
The predetermined gap is set to a size such that the outer peripheral surface does not contact the inner peripheral surface of the cylindrical member even when the common shaft is bent and deformed in the radial direction during engine operation.
A variable valve operating apparatus for an internal combustion engine, wherein the outer peripheral surface of the cylindrical member is rotatably supported by at least two bearings provided at different positions in the axial direction of the cylindrical member. A variable valve operating apparatus for an internal combustion engine according to claim 1 ,
The variable valve operating apparatus for an internal combustion engine, wherein the common shaft is constituted by a drive shaft integrally provided with the drive cam .

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