JP5119180B2 - 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 can vary at least the operating angle (opening period) of an intake valve and an exhaust valve, which are engine valves, according to an engine operating state.

  As is well known, the intake and exhaust valve operating angles are used to improve fuel efficiency at low engine speeds and low loads, to ensure stable operation, and to ensure sufficient output by improving intake charging efficiency at high speeds and high loads. Various variable valve operating devices that variably control the engine according to the engine operating state have been provided, and one of them is described in the following Patent Document 1 previously filed by the present applicant. Yes.

  In brief, a multi-link transmission consisting of a drive cam integrally provided on the outer periphery of a drive shaft that is rotationally driven by a crankshaft, and a rocker arm and a link member that convert the rotational force of the drive cam into a swinging motion. A mechanism, a swing cam that opens and closes the intake valve by sliding on the upper surface of the valve lifter via the transmission mechanism, a base end portion rotatably supported by the drive shaft, and a distal end portion that transmits the transmission A support arm in a substantially lateral state that is rotatably connected to a rocking fulcrum of a rocker arm of the mechanism, a drive mechanism that pivots the tip end side of the support arm in a vertical direction, and the drive mechanism according to an engine operating state. Control means for controlling forward and reverse rotation.

  Then, the operating angle of the intake valve is changed by changing the sliding position of the swing cam with respect to the upper surface of the valve lifter via the rocker arm and the link member of the transmission mechanism by controlling the support arm to rotate up and down by the drive mechanism. The (lift amount) is variably controlled, and when such an operating angle increases, the peak lift phase at the time of valve opening shifts to the retard side.

  For this reason, the closing timing (IVC) of the intake valve can be greatly changed, thereby improving the engine performance described above.

Japanese Patent Laid-Open No. 11-264307 (FIGS. 9 and 10)

  In the conventional variable valve operating apparatus, as shown in FIG. 10 of the publication, the closing timing (IVC) of the intake valve is greatly retarded when the transition is made from the small operating angle to the large operating angle. Although the change with respect to the timing (IVO) is small, it has a characteristic that the advance angle changes uniformly.

  However, the opening timing (IVO) of the intake valve during intermediate operating angle (medium lift) control that is controlled in the low rotation partial load region of the engine is to increase the valve overlap with the exhaust valve to improve fuel efficiency. However, it is desirable that the angle is controlled to be further advanced relative to the conventional technique. However, in the conventional variable valve apparatus, the IVO is uniformly advanced as the operating angle increases. ing.

  This characteristic is due to the fact that the operating angle of the intake valve is changed by the rotation of the entire mechanism of the variable valve operating device.

  As a result, there is a problem that the fuel consumption cannot be sufficiently improved during the middle operating angle control.

  Here, it is conceivable that the valve timing control device (cam phaser) is used in combination with the conventional variable valve device, and the advance angle control is performed during the middle operation angle control of the intake valve. In the case of shifting to the operating angle, there is a concern about interference between the engine valve and the piston or poor torque response if the conversion response to the retard side of the valve timing control device is slow.

The present invention has been devised in view of the technical problem of the conventional variable valve gear, and the invention according to claim 1 is directed to a drive support shaft and a center point at the axis of the drive support shaft. A drive eccentric cam provided eccentrically with respect to the drive shaft, the drive shaft rotating around the drive support shaft in synchronization with the crankshaft, a control support shaft, and a center point at the shaft center of the control support shaft A control eccentric cam provided eccentrically with respect to the control shaft, and a control shaft rotatably provided about the control support shaft. A swing cam for opening and closing the engine valve, a rocker arm swinging with the control eccentric cam as a fulcrum, and a first fulcrum whose one end is the center point of the drive eccentric cam, and swingable to the drive eccentric cam A second fulcrum connected to the rocker arm at the other end The link arm is pivotably linked to the center, and one end is pivotably linked around a third fulcrum provided at a position different from the second fulcrum in the rocker arm, and the other end is oscillated. A variable valve operating device for an internal combustion engine that changes at least the operating angle of the engine valve by rotating the control shaft, the transmission mechanism being linked to a cam,
The position of the control eccentric cam when the engine valve is controlled to an intermediate operating angle that is larger than the minimum operating angle by a predetermined amount is the moment when the valve lift peak lift of the engine valve controlled to the minimum operating angle is reached. Centering on the second fulcrum, the position is on the advance side with respect to the rotation direction of the drive shaft with respect to the first arc line drawn through the center point of the control eccentric cam when controlled to the minimum operating angle. And the opening lift of the engine valve is larger than the second arc line drawn through the center point of the control eccentric cam when the drive shaft is controlled to the minimum operating angle. It is characterized in that it is set so as to be in a position deviating in the direction to be.

  According to the first aspect of the present invention, it is possible to advance the valve opening timing of the engine valve during intermediate operation angle control.

  As a result, for example, the valve overlap at the time of partial load operation increases, and the fuel consumption can be improved.

It is a principal part perspective view of the variable valve apparatus in 1st Example. It is principal part sectional drawing of the variable valve apparatus in a present Example. A is a plan view of a rocker arm used in this embodiment, and B is a side sectional view. A sectional view at the time of minimum operating angle control is shown. A is a sectional view taken along line AA in FIG. 2 when the valve is closed, and B is a sectional view taken along line BB in FIG. A sectional view at the time of minimum operating angle control is shown. A is a sectional view taken along line AA in FIG. 2 at the time of peak lift at the time of valve opening, and B is a sectional view taken along line BB in FIG. A sectional view at the time of intermediate working angle control is shown, A is a sectional view taken along line AA in FIG. 2 when the valve is closed, and B is a sectional view taken along line BB in FIG. A sectional view at the time of intermediate working angle control is shown. A is a sectional view taken along line AA in FIG. 2 at the time of peak lift at the time of valve opening, and B is a sectional view taken along line BB in FIG. Sectional drawing at the time of maximum operating angle control is shown, A is a sectional view taken along line AA in FIG. 2 when the valve is closed, and B is a sectional view taken along line BB in FIG. Sectional drawing at the time of maximum operating angle control is shown, A is a sectional view taken along line AA in FIG. 2 at the time of peak lift at the time of valve opening, and B is a sectional view taken along line BB in FIG. It is a valve lift characteristic figure compared with a present Example and the prior art. It is a valve timing variable characteristic figure compared with a present Example and the prior art. It is a principal part front view of the variable valve apparatus in 2nd Example. A is a plan view of a rocker arm used in the second embodiment, and B is a side sectional view. It is a principal part front view of the variable valve apparatus in 3rd Example. It is a principal part top view by the side of the rocker arm of the variable valve apparatus in 3rd Example. 4 shows a variable valve operating apparatus according to a fourth embodiment, in which A is a cross-sectional view from the same position as the AA line in FIG. 2 at the time of minimum operating angle control, and B is from the same position as the BB line in FIG. It is sectional drawing. 5 shows a variable valve operating apparatus according to a fifth embodiment, wherein A is a cross-sectional view from the same position as the AA line in FIG. 2 during the minimum operating angle control, and B is also from the same position as the BB line in FIG. It is sectional drawing.

Embodiments of a variable valve operating apparatus for an internal combustion engine according to the present invention will be described below in detail with reference to the drawings. In this embodiment, the variable valve device is applied to the intake side of an internal combustion engine.
[First embodiment]
As shown in FIGS. 1 and 2, the variable valve operating apparatus in this embodiment is slidably provided on a cylinder head 1 via a valve guide, and two intake valves 3 per cylinder for opening and closing intake ports. , 3, an internal hollow drive shaft 4 disposed in the longitudinal direction of the engine, and each intake valve 3 via each swing arm 6, 6 that is a follower disposed at the upper end of each intake valve 3, 3. , 3 and a pair of oscillating cams 7, 7 for opening and closing, and a drive eccentric cam 5, which will be described later, and the oscillating cams 7, 7 are linked to oscillate the rotational force of the drive eccentric cam 5. A transmission mechanism 8 that converts to a dynamic motion and transmits it to the oscillating cams 7 and 7 as a oscillating force, and makes the posture of the transmission mechanism 8 variable so that the valve lift amount and the operating angle of each intake valve 3 and 3 are in the engine operating state. And a control mechanism 9 variably controlled according to the above. The operating angle refers to a period during which the intake valves 3 and 3 are open. This operating angle refers to an effective lift section excluding a ramp portion with a gentle slope immediately after the start of lift when the intake valves 3 and 3 are opened and immediately before the end of lift.

  The intake valves 3 and 3 are connected to an intake port by a valve spring (not shown) elastically mounted between a bottom portion of a substantially cylindrical bore housed in an upper end portion of the cylinder head 1 and a spring retainer 10 at the upper end portion of the valve stem. Is biased in the direction of closing each open end.

  The drive shaft 4 includes a drive support shaft 4 a and the drive eccentric cam 5 fixed to the outer periphery of the drive support shaft 4 a, and both end portions are provided by bearing portions 11 provided at the upper part of the cylinder head 1. It is pivotally supported. Further, the drive shaft 4 receives a rotational force from the crankshaft of the engine via a valve timing control device (cam phaser) (not shown) provided at one end, and rotates clockwise (arrow direction) in FIG. It is designed to rotate.

  The drive eccentric cam 5 includes a cam main body 5a formed in a substantially disc shape and a cylindrical boss portion 5b integrally provided on the outer side of the cam main body 5a. It is fixed to the drive support shaft 4a through a fixing pin 12 that is inserted into a pin hole formed in the shaft. The drive eccentric cam 5 is disposed on one end side of the swing cams 7 and 7, and the boss portion 5b is disposed at a position opposite to the swing cams 7 and 7 across the cam body 5a. Has been. Therefore, the cam body 5 a side is located on the swing cams 7, 7 side through the spacer 2. The cam body 5a has a cam profile with an outer peripheral surface formed in an eccentric circle, and the shaft center X is offset from the shaft center Y of the drive support shaft 4a by a predetermined amount in the radial direction. It is configured as a fulcrum X.

  As shown in FIG. 1, each swing arm 6 has a concave lower end 6 a abutting against a stem end of each intake valve 3 and a spherical lower surface of the other end 6 b formed on the cylinder head 1. The hydraulic lash adjuster 13 held in the holding hole 1c is abutted and supported by the spherical head of the hydraulic lash adjuster 13 and swings with the head of the hydraulic lash adjuster 13 as a pivot. Further, the swing arm 6 is rotatably supported by a roller 14 with which each swing cam 7 abuts at a substantially hollow center position.

  As shown in FIGS. 1 and 4, each of the swing cams 7 has a substantially raindrop shape with the same shape, and a cylindrical camshaft 7 a that is fitted on the outer peripheral surface of the drive shaft 4 is provided on the base end side. The cam shaft 7a is integrally formed and supported so as to be swingable about the axis Y of the drive support shaft 4a as the swing support shaft.

  Each swing cam 7 has a cam surface 7d formed on the lower surface between the base end portion and the cam nose portion 7b on the distal end side. The cam surface 7d includes a base circle surface on the base end side, a ramp surface extending in an arc shape from the base circle surface to the cam nose portion 7b, and a peak of a maximum lift from the ramp surface to the tip end side of the cam nose portion 7b. And a base surface, a ramp surface, a lift surface, and a top surface are formed on the outer peripheral surface of the roller 14 of each swing arm 6 according to the swing position of the swing cam 7. It comes into contact with the displaced position.

  Further, in each swing cam 7, the swing direction in which the cam surface 7d moves to the lift surface side to open the intake valves 3 and 3 is set to be the same as the rotation direction (arrow direction) of the drive shaft 4. ing. Therefore, a rotating torque is generated in the direction in which each rocking cam 7 is lifted by the coefficient of friction between the drive shaft 4 and each rocking cam 7. For this reason, the drive efficiency of each rocking cam 7 improves.

  Further, the swing cam 7 on the drive eccentric cam 5 side is integrally provided with a connecting portion 7c at a position opposite to the cam nose portion 7b across the cam shaft 7a. A pin hole through which a connecting pin 20 connected to the other end portion of a link rod 17 described later is inserted is formed in both sides.

  The rollers 14 are arranged so as to protrude from the upper surfaces of the swing arms 6, and a relatively large gap is formed between the upper surfaces of the swing arms 6 and 6. Interference between the swing arms 6 and 6 and the connecting portions 7c of the swing cams 7 and 7 and the other end portion 17b of the link rod 17 is prevented. Therefore, as shown in FIG. 4A, the interference is prevented even at the position where each rocking cam 7 jumps up most. Further, interference between the roller 14 and the connecting portion 7c of the swing cam 7 can be avoided by the left and right clearances as shown in FIG. 4A. Therefore, compared with the case where it applies to the bucket lifter of a plane follower, interference of the connection part 7c becomes difficult to generate | occur | produce.

  As shown in FIGS. 1 to 4, the transmission mechanism 8 includes a rocker arm 15 disposed above the drive shaft 4 along the engine width direction, and a link arm 16 that links the rocker arm 15 and the drive eccentric cam 5. And a link rod 17 that links the rocker arm 15 and the connecting portion 7c of the one swing cam 7 to form a multi-node link mechanism.

  As shown in FIGS. 3A and 3B, the rocker arm 15 has a cylindrical base portion 15a on one end side that is swingably supported by a control eccentric shaft 29, which will be described later, and a fork from the outer surface of the cylindrical base portion 15a to the inside of the engine. It is comprised from the 1st, 2nd arm part 15b, 15c projected in parallel in the shape.

  The cylindrical base portion 15a is formed with a support hole 15d penetratingly formed on the outer periphery of a control eccentric shaft 29 to be described later with a small clearance.

  The first arm portion 15b is integrally provided with a shaft portion 15e that is rotatably linked to a projecting end 16b of the link arm 16, which is described later, on the outer surface of the tip portion. Is configured as the second fulcrum R.

  On the other hand, the second arm portion 15c is provided with a lift adjusting mechanism 21 at a block portion 15f at the tip, and a later-described one end portion of the link rod 17 on a pivot pin 19 described later of the lift adjusting mechanism 21. 17a is rotatably linked, and the axis of the pivot pin 19 is configured as a third fulcrum S. Further, on both side portions of the block portion 15f, elongated holes 15h through which the pivot pins 19 can move in the vertical direction are formed penetrating from the lateral direction.

  The first arm portion 15b and the second arm portion 15c are provided at different angles in the swinging direction and are arranged in a vertically displaced state, and the distal end portion of the first arm portion 15b is the second arm portion 15c. It is inclined downward with a slight inclination angle from the tip.

  The link arm 16 includes an annular portion 16a having a relatively large diameter and the protruding end 16b projecting at a predetermined position on the outer peripheral surface of the annular portion 16a. A fitting hole 16c for fitting and supporting the outer peripheral surface of the drive eccentric cam 5 rotatably is formed.

  Each of the link rods 17 is integrally formed by press molding, is formed in a substantially U-shaped cross section, and the inside is bent in a substantially arc shape for compactness. Each link rod 17 is connected to the second arm portion 15c via the pivot pin 19 having one end portion 17a inserted through the pin hole, and via the connecting pin 20 having the other end portion 17b inserted through the pin hole. The one rocking cam 7 is rotatably connected to the connecting portion 7c. The axial center of the connecting pin 20 is configured as a fourth fulcrum T (see FIG. 4A). Further, since only one link rod 17 is provided per cylinder, the structure can be simplified and the weight can be reduced.

  The link rod 17 lifts the swing cam 7 when the connecting portion 7c is pulled up, but the cam nose portion 7b receiving the input from the roller 14 is disposed on the opposite side of the connecting portion 7c with respect to the swing center. Therefore, the occurrence of falling of each swing cam 7 can be suppressed.

  As shown in FIGS. 1 and 2, the lift adjustment mechanism 21 includes the pivot pin 19 disposed in the long hole 15h of the block portion 15f of the second arm portion 15c of the rocker arm 15, and the block portion 15f. An adjustment bolt 22 screwed from below into an adjustment female screw hole drilled in the lower part toward the long hole, and a fixing female screw hole drilled in the upper part of the block portion 15f toward the long hole. And a locking bolt 23 screwed from above.

  After the assembly of each component, the lift amount of each intake valve 3 and 3 is finely adjusted by adjusting the vertical position of the pivot pin 19 in the long hole 15h by the adjustment bolt 22, and the adjustment work The position of the pivot pin 19 is fixed by tightening the locking bolt 23 at the end of the operation.

  The control mechanism 9 includes a control shaft 24 disposed above the drive shaft 4 in parallel with the drive support shaft 4a, and an electric actuator, which is an unillustrated actuator that rotationally drives the control shaft 24.

  As shown in FIGS. 1, 2, and 4, the control shaft 24 includes a control support shaft 24 a and a plurality of swing support points of the rocker arm 15 provided on the outer periphery of the control support shaft 24 a for each cylinder. And a control eccentric cam 25.

  The control support shaft 24a is formed with recesses 24b and 24c having a two-sided width at positions corresponding to the respective rocker arms 15, and two axially spaced two recesses 24b and 24c are provided between the recesses 24b and 24c. Bolt insertion holes 26a and 26b are formed penetrating along the radial direction. Each of the recesses 24b and 24c extends along the axial direction of the control support shaft 24a, and each bottom surface is formed as a flat surface.

  The control eccentric cam 25 is fixed to the one recess 24b through two bolts 27, 27 inserted from the other recess 24c side into the bolt insertion holes 26a, 26a, and the bracket 28. And a control eccentric shaft 29 fixed to the tip end side of the head.

  The bracket 28 is formed in a substantially U-shaped side surface, is extended along the longitudinal direction of the one recess 24b, and has a rectangular base 28a fitted and held in the one recess 24b. It comprises arm-shaped fixing pieces 28b and 28b projecting downward in FIG. 2 at both ends in the longitudinal direction of the base 28a.

  The base portion 28a is formed with female screw holes into which the tip ends of the bolts 27, 27 are screwed on both end sides in the longitudinal direction, while the two fixing pieces 28b, 28b are provided with the control eccentricity on each tip side. Fixing holes 28c and 28c for fixing the shaft 29 are formed through. Further, the bracket 28 has an outer surface of the base portion 28a in contact with the bottom surface of the one concave portion 24b, and the outer end edges of both the fixing pieces 28b and 28b are in close contact with the inner surface facing the one concave portion 24b. The positioning accuracy in the longitudinal direction is increased because it is fitted and held in contact with.

  The control eccentric shaft 29 supports the rocker arm 15 on the outer peripheral surface thereof through a support hole 15d of the cylindrical base portion 15a of the rocker arm 15 so that the rocker arm 15 can swing, and its axial length L is the bracket 28. These two support pieces 28b, 28b are set to be substantially the same as the outer surfaces thereof, and both end portions thereof are fixed in the fixing holes 28c, 28c by press-fitting or the like. An axis serving as a rocking fulcrum of the rocker arm 15 is configured as a fifth fulcrum Q.

  And, within the length L of the control eccentric shaft 29, the outer surface of the cam body 5a of the drive eccentric cam 5 to the outer surface of the link rod 17 including the one swing cam 7 is arranged. .

  Further, as shown in FIGS. 4A and 4B, the fifth fulcrum Q of the control eccentric shaft 29 is relatively large from the axis P of the control support shaft 24a depending on the length of the arms of both support pieces 28b and 28b of the bracket 28. It is eccentric with an eccentric amount α. In other words, since the control eccentric shaft 29 is formed in a crank shape with respect to the axis P of the control support shaft 24a via the bracket 28, the amount of eccentricity α can be made sufficiently large. It can be done.

  The control eccentric cam 25 is not only constituted by the bracket 28 and the control eccentric shaft 29, but can also be a simple columnar structure fixed integrally on the outer periphery of the control support shaft 24a. is there. This also makes it possible to improve rigidity.

  The electric actuator includes an electric motor (not shown) fixed to the rear end of the cylinder head 1 and a speed reducer such as a ball screw mechanism that transmits the rotational driving force of the electric motor to the control support shaft 24a. Has been.

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

  This electronic controller includes various sensors such as a crank angle sensor that detects the engine speed, an air flow meter that detects the intake air amount, a water temperature sensor that detects the engine water temperature, and a potentiometer that detects the rotational position of the control shaft 24. The detection signal from is fed back to detect the current engine operating state by calculation or the like, and the control signal is output to the electric motor. According to the actuator driven to rotate by such an electric motor, quick switching response can be expected regardless of the oil temperature of the engine.

  In this embodiment, a valve timing control device is provided at the front end of the drive support shaft 4a so that the opening / closing timing of the intake valves 3, 3 can be varied according to the engine operating state. The valve timing control device (cam phaser) is of a known vane type, for example, and is generally arranged at the front end portion of the drive support shaft 5a, and receives rotational force from the crankshaft. Is transmitted to the timing sprocket, a vane member rotatably disposed inside the cylindrical housing of the timing sprocket, and fixed to the front end portion of the drive support shaft 4a, and between the housing and the vane member A hydraulic circuit that selectively supplies and discharges hydraulic pressure to and from the advance hydraulic chamber and the retard hydraulic chamber. The operation of the electromagnetic switching valve that switches between supplying and discharging the hydraulic pressure from the oil pump of the hydraulic circuit to the hydraulic chambers is controlled by the electronic controller. Since this type of valve timing control device uses hydraulic pressure as a driving source, it generally has a slow operation response and is easily affected by the oil temperature.

  In this embodiment, by controlling the rotational position of the control support shaft 24a by the electric actuator according to the engine operating state, the valve lift amount and the operating angle of the intake valves 3, 3 are maximized from the minimum operating angle. The operating angle is controlled up to the operating angle, but the intermediate operating angle is determined by specifying the positional relationship of the first fulcrum X, the second fulcrum R, the third fulcrum S, etc. according to the rotational position of the control support shaft 24a. The opening timing of the valve lift characteristic at the time of control is changed to the advance side.

  Hereinafter, in the description of the operation of the variable valve operating apparatus of the present embodiment, the specific valve lift characteristics will be described in detail.

  That is, first, when the drive support shaft 4 a is rotated in the direction of the arrow in FIG. 1 by the crankshaft, the drive eccentric cam 5 is also rotated in the same direction, and the rocker arm 15 is connected via the link arm 16 to the fifth fulcrum Q of the control eccentric shaft 29. And the link rod 17 is lifted or pulled down to open / close the intake valves 3 and 3 via the rollers 14 by the cam surfaces of the swing cams 7 and 7.

  Then, for example, in a low rotation range such as during idling operation of the engine, the electric motor is driven to rotate by a control signal from the controller, and this rotational torque causes the control support shaft 24a to be positioned counterclockwise θ1. Driven by rotation. Therefore, as shown in FIGS. 4 and 5, the control eccentric shaft 29 is similarly positioned at θ 1, and the fifth fulcrum Q moves away from the drive shaft 4 in the upper left direction. As a result, the entire transmission mechanism 8 tilts counterclockwise about the drive support shaft 4a. For this reason, each rocking cam 7 also rotates counterclockwise, and the contact position of the roller 14 is closer to the base circle side of the cam surface 7d.

  Therefore, when the rocker arm 15 is pushed up via the link arm 16 as the drive eccentric cam 5 rotates, the connecting portion 7c of the rocking cam 7 is lifted via the link rod 17 as shown in FIG. The valve is rotated clockwise and the lift is transmitted to the needle roller 14 of the swing arm 6 for valve lift, but the lift amount and the operating angle are sufficiently small.

  Therefore, in the low-rotation light load region of such an engine, the valve lift amount L1 of each intake valve 3 becomes sufficiently small as shown in FIG. 10, thereby delaying the opening timing of each intake valve 3 and No valve overlap. For this reason, improvement in fuel consumption and stable engine rotation can be obtained by improving combustion.

  At the time of peak lift of each intake valve 3, as shown in FIGS. 5A and 5B, the eccentric direction XY line with respect to the axis Y of the drive support shaft 4 a of the first support point X of the drive eccentric cam 5 is the link arm 16. This is a moment that coincides with the biaxial line X-R with the second fulcrum R.

  At this time, the eccentric direction YX of the drive eccentric shaft 4a is at a position rotated by α1 in the rotation direction (clockwise) of the drive support shaft 4a as shown in FIG.

  Here, an angle ∠XR-Q1 formed by a straight line (extension line) connecting the biaxial directions XR of the link arm 16 and a straight line (line segment) connecting the rotation position directions Q1-R of the rocker arm 15 is β1. In other words, β1 is a relatively large value.

  Next, considering the line RS connecting the third fulcrum S of the link rod 17 on the rocker arm 15, the angle γ1 formed by the XR line in the biaxial direction of the link arm 16 and the RS line is Then, it is expressed by the following formula.

γ1 = ∠Q1-RS− (180 ° −β1) = β1- (180 ° −∠Q1-RS)
Here, since the value in the parentheses is a fixed value, γ1 has a direct correlation with β1.

  At the moment of peak lift during the aforementioned minimum operating angle (minimum lift) control, β1 is relatively large and γ1 is also relatively large.

  Next, when the engine operating state shifts to the low / medium rotation partial load region, the control shaft 24 counterclockwise to the position θ2 as shown in FIGS. 6 and 7 by the control signal from the electronic controller via the electric actuator. The control eccentric shaft 29 is also rotated to the position θ2, and the fifth fulcrum Q2 which is the center of the control eccentric cam 25 is closest to the drive support shaft 4a.

  For this reason, the entire transmission mechanism 8 such as the rocker arm 15 and the link arm 16 is rotated clockwise around the drive support shaft 4a, whereby the swing cams 7 and 7 are also relatively clockwise (lift direction). To turn.

  Accordingly, when the peak lift is reached when the valve is opened, as shown in FIGS. 7A and 7B, the lift of the swing cam 7 is transmitted to the needle roller 14 of the swing arm 6 and the valve lifts. Increase to intermediate lift and intermediate operating angle.

  Therefore, the valve lift amount L2 and the operating angle of each intake valve 3 increase as shown in FIG.

  The eccentric direction YX (drive shaft angle α2) of the first fulcrum X of the drive eccentric cam 5 with respect to the axis Y of the drive support shaft 4a at the time of peak lift is clockwise compared with the minimum operation angle control. Move to (retard side) (α1 <α2).

  Therefore, as shown in FIG. 10, the peak lift phase of the valve lift at the intermediate operating angle shifts to the retard side as compared with the minimum operating angle (L1).

  Here, since the control eccentric shaft 29 is directed to the drive shaft 4 side, at the moment of peak lift (see FIGS. 7A and 7B), the X-R straight line (matches the Y-R straight line) and R The angle β2 formed by the straight line −Q2 is minimized. This is because the length of the triangular Y-Q2 formed in Y-R-Q2 is minimized (Q2-R and YR are fixed values).

  Therefore, γ2 is also minimized, and this is a characteristic that the lift start timing (IVO) of the valve lift locus shown in FIG. 10 swells toward the advance side. This characteristic will be described later.

  Further, for example, in the case of shifting to the high engine rotation range, when the electric motor further rotates the control support shaft 24a counterclockwise via the speed reducer by the control signal from the electronic controller, it is shown in FIGS. As described above, the control eccentric shaft 29 also rotates in the same direction, and the fifth fulcrum Q3 of the control eccentric shaft 29 moves to a position away from the drive shaft 4 in the right direction (substantially symmetrical with the minimum operation angle control). position).

  For this reason, as shown in FIGS. 8 and 9, the entire transmission mechanism 8 is further rotated in the clockwise direction, so that the swing cams 7 and 7 are further rotated in the clockwise direction (lift direction). Move. Therefore, when the peak lift is reached when the valve is opened, as shown in FIGS. 9A and 9B, the lift of each swing cam 7 is transmitted to the needle roller 14 of the swing arm 6 and the valve lifts. Will further increase to the maximum lift and maximum operating angle.

  Therefore, in such a high rotation region, as shown in FIG. 10, the valve lift amount L3 and the operating angle become maximum, and the opening timing (IVO) of each intake valve 3 becomes earlier than L1, but the advance angle with respect to L2 is suppressed. As a result, the valve overlap with the exhaust valve increases moderately, and the closing timing is sufficiently delayed. As a result, the intake charging efficiency is improved and a sufficient output can be secured.

  The eccentric direction YX (drive shaft angle α3) of the first fulcrum X of the drive eccentric cam 5 with respect to the axis Y of the drive support shaft 4a during the peak lift is further compared to that during the intermediate operation angle control. Move in the direction (retard side) (α2 <α3). On the other hand, the angle β3 increases again with respect to β2, and therefore the angle γ3 increases again with respect to γ2.

  As described above, the lift timing (IVO) of the valve lift at the intermediate operating angle is in a state of expanding toward the advance side because the angle γ2 at the intermediate operating angle is the minimum operating angle control time. This is because it is relatively smaller than the angle γ1 at the angle γ1 and the angle γ3 at the maximum operating angle control.

  That is, at the intermediate operating angle, as shown in FIG. 7B, when the angle γ is relatively small, the pivot pin 19 that connects the second arm portion 15c of the rocker arm 15 and the one end portion 17a of the link rod 17 is connected. Since the third fulcrum S of the link rod 17 is relatively lifted, the fourth fulcrum T at the linkage position of the other end 17b of the link rod 17 with the swing cam 7 is lifted, and the swing cams 7, 7 are moved in the lift direction. (Displacement) increases the lift amount and operating angle. At this time, the peak lift phase α2 does not change.

  Here, assuming that there is no effect of the angle change of γ, FIG. 5B shows the moment of peak lift during the minimum operating angle control, which is the center of the control eccentric cam 25 at that time. The fifth fulcrum is point Q1.

  For example, when the entire mechanism rotates around the drive shaft as in the conventional variable valve operating device described in Patent Document 1 described above, the locus of the fifth fulcrum is the second arc around the drive shaft. It will move on the line. In this case, since β is the entire rotation of the mechanism, β remains unchanged as β1, and γ remains unchanged as γ1. Therefore, the lift curve when the peak lift phase becomes α2 has a lift curve characteristic as shown by a broken line in FIG. 10, and the peak lift locus (broken line Z1) is substantially the same as that of the conventional variable valve apparatus. It becomes a linear characteristic.

  On the other hand, in the present embodiment, the fifth fulcrum is a point Q2 shown in FIG. 5B, which is on the drive shaft 4 side (arrow direction) with respect to the second arc line. That is, the third arc line passing through the point Q2 with the drive shaft 4 as the center is on the drive axis 4 side with respect to the second arc line.

  Therefore, as described above, since the angle of γ changes and becomes smaller (γ1 → γ2), the lift displacement (swing) of the swing cams 7 and 7 increases, and the lift amount and the operating angle increase. At this time, since the peak lift phase does not change (regardless of γ), as shown by the arrow in FIG. 10, the lift amount and the operating angle increase due to the unchanged peak lift phase. It becomes a curve characteristic. Therefore, as shown in the figure, the peak lift locus Z2 swells in a curved shape toward the advance side in the intermediate operating angle region.

  Further, as apparent from the description of FIG. 5B, the point Q2 is clockwise (arrow direction) from the first arc line a passing through the point Q1 with the point R as the center, that is, with respect to the rotational direction of the drive shaft 4. On the advanced side.

  That is, if the intersection point of the first arc line a and the third arc line c is Q2 ′, both the points Q1 and Q2 ′ are on the first arc line a, and therefore the center of the control eccentric cam 25 is the point Q1. Since the angle of the link arm 16 does not change even when moving from Q to the point Q2 ′, the phase of the drive shaft 4 of the peak lift does not change. Then, the point Q2 ′ moves from the point Q2 ′ to the point Q2 along with the link arm 16 in the rotation direction of the drive shaft 4 on the third arc line c. That is, it means that the drive eccentric cam 5 does not reach the peak lift unless it further rotates during the intermediate operation angle control. Therefore, the peak lift phase is retarded from α1 to α2, the closing timing (IVC) of the intake valve 3 as described above is sufficiently delayed, and the opening timing (IVO) swells to the advance side as described above, and the peak lift The trajectory also bulges in a curved shape.

  Further, when the maximum operating angle is reached, the fifth fulcrum of the control eccentric cam 25 moves to a point Q3 in FIG. 5B. This position moves further to the clockwise side (arrow direction) from the first arc line a than the point Q2. This is on the retard side with respect to the rotation direction of the drive shaft 4. Therefore, the peak lift phase is further retarded from α2 to α3.

  On the other hand, with respect to the second arc line b, the point Q3 approaches again and moves substantially on the second arc line b. As a result, as described above, γ increases again (γ2 → γ3), so that the operating angle decreases with respect to the same α3.

  For this reason, the opening timing (IVO) of the intake valve 3 and the peak lift phase, which have tended to advance at the intermediate operating angle (point Q2), again move in the retarding direction. Therefore, the IVO and peak lift phase in FIG. 11 tend to be upwardly convex, and the peak lift phase in FIG. 10 also tends to be upwardly convex to the left.

  As described above, the specific change in the IVO and peak lift phase of the intake valve 3 in this embodiment is based on the position of the fifth fulcrum Q, which is the center of the control eccentric cam 25, with respect to the first arc line a and the second arc line b. Can be explained.

  FIG. 11 shows the opening / closing timing (valve timing) of the intake valves 3 and 3 on the vertical axis and the operating angle on the horizontal axis, respectively, according to this embodiment (solid line) and the prior art (dashed line). This is a comparison of variable valve timing characteristics.

  Looking at the opening timing (IVO) characteristics of the intake valve 3 of the present embodiment on the upper side of this figure, the IVO reaches the most advanced angle in the vicinity from the intermediate operating angle to the maximum operating angle. In this state, the intake valve It is set so that the interference between the pistons 3 and 3 and the piston can be avoided, that is, the allowable IVO is not exceeded.

More specifically, cam timing pulley is the technique described in rotating or performed by a drive shaft setting the attachment phase of the timing pulley for transmitting to (camshaft), or JP 2006- 30 7658 JP crankshaft When the phaser (variable phase valve timing control device) is used, the IVO characteristic (this embodiment) shown in FIG. 10 is set at the most advanced angle phase by the cam phaser, and the allowable IVO is set not to be exceeded. .

  The IVO (medium) during the intermediate operation angle control is set closer to the advance angle than the conventional IVO, as is apparent from FIG.

  Therefore, in this embodiment, when the engine is controlled to the intermediate operating angle in the low or middle engine speed range or in the partial load range, the IVO sufficiently advances with respect to the prior art, so that the valve overlap with the exhaust valve can be increased. As a result, the internal EGR can be increased, and the fuel efficiency can be improved.

  Moreover, even if the operating angle is expanded and controlled from the acceleration request of the engine thereafter, the IVO slightly advances to the maximum, but does not exceed the allowable IVO.

  On the other hand, regarding the prior art, as indicated by the broken line in FIG. 11, the IVO changes, but the IVO (medium) at the intermediate operating angle cannot be advanced sufficiently as in the present embodiment, so the valve overlap is reduced. Therefore, fuel consumption cannot be improved and NOx cannot be reduced.

  Here, in the prior art, the cam phaser is provided, and thereby the valve timing is advanced, and as shown by the arrow in FIG. 11, it can be taken to the IVO (middle) position of this embodiment. When the operation angle is further enlarged and controlled by an acceleration request or the like, if the conversion response to the retarded side of the cam phaser is poor, it shifts to the star mark in FIG. 11 and exceeds the allowable IVO. As a result, the intake valve 3 , 3 and the piston may occur. Therefore, a large valve recess for preventing interference must be formed on the upper surface of the piston, which may cause a cooling loss, deteriorate fuel consumption, and increase HC exhaust emissions.

  Also, a method of enlarging the operating angle according to the state of conversion of the cam phaser to the retard angle side is conceivable, but this cam phaser is generally slow in response because the hydraulic pressure is the drive source. In addition, there is a large variation in control of transient motion control due to such increase control, and considering safety, it is necessary to increase the valve recess, resulting in deterioration of fuel consumption. Further, although it is conceivable that the expansion control of the operating angle is extremely slow, if this is done, the acceleration performance may be greatly deteriorated and the drivability may be greatly reduced.

  On the other hand, in the present embodiment, the interference between the intake valves 3 and 3 and the piston is prevented regardless of the operating angle regardless of the cam phaser or the most advanced angle side. Since it is not necessary to consider the variation in control of motion control, it is not necessary to form a large valve recess. Thereby, qualities such as fuel consumption and exhaust emission can be improved.

  Further, even when the control response to the retard side of the cam phaser is slow, the operating angle can be expanded without interference between the intake valves 3 and 3 and the piston, so the acceleration response is also good. In addition, since the IVO during the intermediate operation angle control can be sufficiently advanced, the fuel consumption at a partial load can be improved by increasing the valve overlap, and the exhaust emission performance can be improved.

  Further, when the cam phaser is applied to the present embodiment, the engine rotation stability can be obtained by controlling the minimum operating angle during idling operation and further controlling the cam phaser to the retard side. As shown in the cam phaser retard angle (1) in FIG. 11, because IVO is delayed from the top dead center, the valve overlap is eliminated, the internal EGR is greatly reduced, and the intake swirl is increased. Is to improve.

  In addition, a small operating angle (lift characteristic above L1 in FIG. 10) is set to be slightly larger when idling when cold, and retarded by the cam phaser improves combustibility and reduces HC emissions. it can. That is, as shown in the cam phaser retard angle (2) in FIG. 11, the operating angle is slightly large, and in addition to being able to produce torque sufficient to overcome the increase in engine friction during cold operation, the closing timing of the intake valves 3 and 3 Since (IVC) is in the vicinity of the bottom dead center, the effective compression ratio is improved and the combustion at the time of cold is improved. Note that there is no problem in the direction in which it is difficult to interfere with the piston as the cam phaser is retarded.

  Further, in the present embodiment, the control eccentric shaft 29 is oriented to the drive support shaft 4a at the time of intermediate operation angle control, so that the control shaft 24 can be easily positioned at the time of assembly of each component. An intermediate operating angle setting having the IVO characteristic can be obtained.

  Further, as shown in FIG. 2, since the rocker arm 15, the link arm 16, the link rod 17, and the drive eccentric cam 5 are arranged within the range of the length L of the control eccentric shaft 29, the apparatus can be made compact. In particular, the operation of the rocker arm 15 can be stabilized, and the falling behavior caused by the falling moment of the rocker arm 15 during operation can be reduced. Moreover, since the drive eccentric cam 5 is arranged on the opposite side in the axial direction from the link rod 17 on the cylindrical portion 5b side, the axial distance between the cam body 5a and the link rod 17 can be shortened. The tilting moment itself of the rocker arm 15 can be reduced, and the behavior of the rocker arm 15 can be stabilized.

  Further, since the control support shaft 24a and the control eccentric shaft 29 of the control shaft 24 are formed separately via the bracket 28, the control support shaft 24 is sub-assembled to the control eccentric shaft 29 and the control support shaft is assembled during assembly work. Since it can be assembled to the shaft 24a, the assembly workability is improved.

  Furthermore, in this embodiment, since the valve timing control device (cam phaser) is also provided, the lift phase of the intake valves 3 and 3 can be freely converted according to the engine operating state. Detailed opening / closing timing control is possible. In particular, regardless of the control operating angle, even when the valve timing control device is controlled to the advance side, it is possible to suppress the interference with the piston. As a result, the problem of interference with the piston is eliminated, the operating angle conversion speed can be increased, and the acceleration response can be further improved. Here, if the electric actuator has a good conversion response, the acceleration response can be further improved.

  Further, since the control eccentric shaft 29 is fixed between the two fixed pieces 28b, 28b of the bracket 28, the control eccentric shaft 29 is supported stably and in a balanced manner with respect to the control support shaft 24a.

  In the present embodiment, a method of lifting the link arm 16 by pushing it up is employed. According to this, since the link arm 16 operates with high rigidity, the valve motion characteristics are stabilized. Because the link arm 16 is only compressed between two axes, the deformation is small. On the contrary, when the link arm 16 is pulled, the annular portion is deformed, so that the amount of deformation increases.

  In the first embodiment, an example in which the third fulcrum S is outside the extended line of the straight line connecting the first fulcrum X and the second fulcrum R is shown. In this case, during the intermediate operation angle control, The straight line connecting the second fulcrum R and the third fulcrum S becomes a direction approaching the straight line connecting the first fulcrum X and the second fulcrum R (direction in which γ decreases), and as described above, the IVO advances during the intermediate operation angle control. The effect of swelling to the corner side is obtained. That is, in this case, as shown in FIG. 5B, the point Q2 at the intermediate working angle is located in the region closer to the drive shaft 4 than the second arc b, and this region increases the lift and the working angle due to the γ effect. It is an area.

  On the other hand, the present embodiment can also be applied to the case where the third fulcrum S is inside the extended line of the straight line connecting the first and second fulcrums X and R.

  That is, in this case, the direction in which the straight line connecting the second fulcrum R and the third fulcrum S rotates counterclockwise (the straight line connecting the second fulcrum R and the third fulcrum S is the first fulcrum X and the second fulcrum. In this case, the above-mentioned effect of IVO expanding during the intermediate operation angle control can be obtained. In FIG. 5B, this can be realized by changing the center P of the control support shaft 24a from the upper right position to the upper left position while keeping the point Q1 as it is. In other words, in this case, when the control shaft 24 is twisted counterclockwise to control the intermediate operating angle, the point Q2 is an area outside the second arc line b.

  Then, since the β increases from β1 to β2 at the point Q1 → Q2, the straight line connecting the second fulcrum R and the third fulcrum S rotates counterclockwise, and the desired IVO and peak lift phase Can swell at an intermediate working angle.

  In any case, when the straight line connecting the second fulcrum R and the third fulcrum S changes in the direction of increasing the lift amount and the operating angle in the control range of the intermediate operating angle, the aforementioned IVO performs the intermediate operating angle control. An effect that sometimes swells can be obtained.

  In short, the center point Q2 of the control eccentric cam 25 in the intermediate operating angle region is positioned on the lift increasing side with respect to the second arc line b passing through the minimum operating angle control Q1, and as described above, during the small operating angle control. It suffices if the first arc line a passing through the center point R at the moment of peak lift is retarded in the direction of the drive shaft 4.

[Second Embodiment]
FIGS. 12 and 13 show a second embodiment. The basic structure is the same as that of the first embodiment, but the structure of the first arm portion 15b of the rocker arm 15 is changed.

  That is, the tip end portion of the first arm portion 15b is formed in a bifurcated shape, and the projecting end of the link arm 16 is inserted into the fixing holes 15g, 15g formed through the tip portion of the bifurcated portions 15b, 15b from the lateral direction. Both ends of the connecting pin 30 that is rotatably connected to the 16b are press-fitted and fixed.

  Therefore, according to the second embodiment, the same effect as that of the first embodiment can be obtained, and the connecting pin 30 is supported in a bifurcated manner by the first arm portions 15b and 15b. Therefore, the support rigidity is improved, the inclination of the protruding end 16b of the link arm 16 is prevented, and the support can be supported stably and reliably.

  In order to prevent the axial displacement of the connecting pin 18, the connecting pin 18 may be press-fitted into the pin hole of the link arm 16, and on the link rod 17 side, either the inner flange or the outer flange, or You may press-fit into both. Further, it is possible to prevent the snap ring from coming off without press-fitting.

[Third embodiment]
FIGS. 14 and 15 show a third embodiment in which the drive eccentric cam 5 is disposed between the swing cams 7 and 7 and a pair of link rods 17 and 17 are provided for each cylinder.

  That is, the concave portion 24b on the bracket 28 side of the control support shaft 24a is extended in the axial direction, and the bracket 28 of the control eccentric cam 25 is also extended in the axial direction. 29 is formed to extend in the axial direction.

  The rocker arm 15 is formed such that the axial width of the cylindrical base portion 15a is extended, and symmetrical first arm portions 15b and 15b protruding forward from the cylindrical base portion 15a are formed in a bifurcated shape. The projecting second arm portions 15c and 15c are integrally formed on the upper portions of the first arm portions 15b and 15b, respectively, and the first arm portions 15b and 15b are formed between the first arm portions 15b and 15b as in the second embodiment. Further, the protruding end 16b of the link arm 26 is rotatably connected through a long connecting pin 30.

  The two second arm portions 15c, 15c are respectively connected to the boss portions 15f, 15f at the distal end portions of the pair of link rods 17, 17 on the pivot pins 19, 19 of the lift adjusting mechanisms 21, 21. Are rotatably connected.

  Each of the swing cams 7 and 7 is divided into left and right parts, and the cam shafts 7a and 7a are swingably supported in an independent state on the outer periphery of the drive support shaft 4a.

  The drive eccentric cam 5 is integrally connected to the drive support shaft 4a by a fixing pin 12 press-fitted from the inner radial direction of the cam body 5a, and spacers 2, 2 are connected to both the swing cams 7, 7. It is arranged in a sandwiched state via.

  Therefore, according to this embodiment, the intake valves 3, 3 are opened and closed via the swing cams 7, 7 by the two link rods 17, 17 on both ends of the rocker arm 15. The rocker arm 15 can be sufficiently prevented from falling in the axial direction. As a result, the transmission mechanism 8 as a whole can be operated stably at all times, and the contact of each part can be suppressed, so that uneven wear can be prevented.

  Moreover, since the swing cams 7 and 7 swing independently of each other, the lift amounts of the intake valves 3 and 3 are made different by changing the cam profiles of the cam surfaces 7d and 7d, for example. Is also possible. As a result, the intake swirl in the cylinder can be increased during the minimum lift control, and the combustibility is improved.

[Fourth embodiment]
16A and 16B show a fourth embodiment (corresponding to the invention of claim 5), and basic structures such as the control shaft 24, the swing cam 7, and the link rod 17 are the same as those of the first embodiment. However, the link arm 16 is eliminated and the drive eccentric cam 5 is changed to a general drive cam 31. This corresponds to FIGS. 5A and 5B.

  Specifically, a roller 32 is attached to the tip end portion of the first arm portion 15 b of the rocker arm 15 via a roller shaft 33.

  On the other hand, a raindrop (egg-shaped) drive cam 31 is integrally fixed to the drive support shaft 4a of the drive shaft 4, and the circular base 31a of the drive cam 31 is fixed to the drive support shaft 4a by press-fitting or the like. In addition, the outer peripheral surface 31b is in rolling contact with the outer peripheral surface of the roller 32 as a cam surface.

  The roller 32 is urged toward the outer peripheral surface of the drive cam 31 by a coil spring 33 as urging means. That is, one end of the coil spring 33 is held by the rocker cover 34 and the other end is held by the upper surface of the first arm portion 15b of the rocker arm 15, so that the outer peripheral surface of the roller 32 is always driven. The cam 31 is in elastic contact with the outer peripheral surface.

  Here, the lift top position X ′ of the cam nose portion 31 a of the drive cam 31 shown in FIG. 16 corresponds to the first fulcrum X of the protruding end 16 b of the link arm 16 of the first embodiment, and the shaft of the roller shaft 33 of the roller 32. The heart R ′ corresponds to the second fulcrum R of the first embodiment.

  The direction of the straight line connecting YX ′ and the straight line connecting X′-R ′ at the peak lift of the intake valves 3 and 3 is the same as in the first embodiment. The phase of the straight line corresponds to the phase α2 of the drive support shaft 4a of the first embodiment.

  The third fulcrum S, which is the axis of the link rod 17, is the same as that of the first embodiment, and is an angle γ1 formed by an extension line of a straight line connecting X′-R ′ and a straight line connecting R′-S. Corresponds to γ1 of the first embodiment.

  Accordingly, the center point Q2 during the intermediate operation angle control is also the same position as the position shown in FIG. 5 of the first embodiment. Therefore, the same effect as the first embodiment can be obtained.

[Fifth embodiment]
FIG. 17 shows a fifth embodiment (corresponding to the invention of claim 4), wherein the link rod 17 pushes down the end of the swing cams 7, 7 on the cam nose portion 7b side to open the intake valves 3, 3. It is comprised so that it may make it.

  17A and 17B, the control eccentric cam 25 is directed downward (control shaft angle θ1, control eccentric cam center point Q1), and is in a state of minimum operating angle control.

  Unlike the other embodiments, the rotation direction of the drive shaft 4 (drive eccentric cam 5) is counterclockwise in FIG.

  When the control shaft 24 is rotated in the clockwise direction, the center point Q of the control eccentric cam 25 is changed from the point Q1 to the point Q2, and is controlled to the middle operating angle.

  The point Q2 is advanced in the rotational direction of the drive shaft 4 with respect to the first arc line a passing through the point Q1. Therefore, the peak lift phase of the intermediate operating angle is retarded as in the other embodiments.

  Moreover, it has deviated from the 2nd circular arc line b which passes the said point Q2, ie, the lift increase direction.

  Therefore, as in the other embodiments, it is possible to advance the valve opening timing of the intake valves 3 and 3 during intermediate operation angle control.

  Here, the outside of the second arc line b passing through the point Q2 (different from the other embodiments) is in the lift increasing direction. When γ increases to γ2, the link rod 17 pushes the swing cams 7 and 7 down. This is to increase the lift.

  Note that it is easier to understand if a third arc line c passing through the point Q2 at the center of the drive shaft 4 is assumed. Here, an intersection of the third arc line c and the first arc line a is defined as a point Q2 ′.

  Even if the position of the center point of the control eccentric cam 25 moves from the point Q1 to the point Q2 ′, the position of the link arm 16 does not change, so the peak lift phase does not change, but since γ increases, the lift amount increases. is there.

  Next, when moving from the point Q2 ′ to the point Q2, it moves together with the link arm 16 on the third arc line c in the rotational direction of the drive shaft 4 toward the advance side. That is, it means that the drive eccentric cam 5 does not reach the peak lift unless it further rotates during the intermediate operation angle control. Therefore, the peak lift phase is retarded as in the other embodiments. For this reason, as in the other embodiments, the IVC is sufficiently delayed, the IVO swells toward the advance side as described above, and the peak lift locus also swells in a curved shape.

  The present invention is not limited to the configuration of each of the above embodiments. For example, in each of the above embodiments, the second fulcrum R of the rocker arm 15 and the link arm 16 is the third fulcrum of the rocker arm 15 and the link rod 17. Although the case where it is relatively close to S is shown, it may be further away. That is, specific coordinates of each fulcrum can be selected as appropriate.

  Furthermore, although the operating angle of the intake valves 3 and 3 in each of the above embodiments is shown by the open period excluding the ramp portion, it may be an operating angle including the ramp section, and the effect is the same.

  In each of the above embodiments, the case where the present invention is applied to the intake valve side has been described. However, the present invention can also be applied to the exhaust valve side or both.

  The follower may be a bucket lifter having a flat upper surface instead of the swing arm shown in the above embodiment.

1 ... Cylinder head 3 ... Intake valve (engine valve)
DESCRIPTION OF SYMBOLS 4 ... Drive shaft 5 ... Drive eccentric cam 7 ... Swing cam 8 ... Transmission mechanism 9 ... Control mechanism 15 ... Rocker arm 15a ... Cylindrical base part 15b ... 1st arm part 15c ... 2nd arm part 16 ... Link arm 17 ... Link rod DESCRIPTION OF SYMBOLS 18 ... Connecting pin 24 ... Control shaft 24a ... Control support shaft 25 ... Control eccentric cam 28 ... Bracket 29 ... Control eccentric shaft a ... 1st circular arc line b ... 2nd circular arc line c ... 3rd circular arc line X ... 1st fulcrum ( (Drive eccentric cam shaft center)
Y ... axis of drive shaft R ... second fulcrum (link point between link arm and first arm)
S ... 3rd fulcrum (connection point of 2nd arm part and link rod)
T: Fourth fulcrum (connection point between the other end of the link rod and the swing cam)
P: Control spindle axis Q: Fifth fulcrum (control eccentric axis)

Claims (5)

A drive shaft, and a drive eccentric cam having a center point eccentrically provided with respect to the axis of the drive support shaft, and a drive shaft that rotates in synchronization with a crankshaft around the drive support shaft;
A control shaft, a control eccentric cam provided with a center point eccentrically provided with respect to the axis of the control support shaft, and a control shaft provided rotatably about the control support shaft;
A swing cam that is swingably supported by the swing support shaft and that opens and closes the engine valve by the cam surface;
A rocker arm that swings about the control eccentric cam as a fulcrum;
One end side is pivotably linked to the drive eccentric cam about a first fulcrum that is the center point of the drive eccentric cam, and the other end side is pivotable about a second fulcrum provided on the rocker arm. Linked link arms,
A transmission mechanism in which one end side is pivotably linked around a third fulcrum provided at a position different from the second fulcrum in the rocker arm, and the other end side is linked to the swing cam;
A variable valve operating apparatus for an internal combustion engine that changes at least an operating angle of an engine valve by rotating the control shaft,
The position of the control eccentric cam when the engine valve is controlled to an intermediate operating angle larger than a minimum operating angle by a predetermined amount,
A first image drawn through the center point of the control eccentric cam when controlled to the minimum operating angle centered on the second fulcrum at the moment when the valve lift peak lift of the engine valve controlled to the minimum operating angle is reached. And set so as to be a position on the advance side as seen from the rotational direction of the drive shaft from one arc line,
A position deviating in the direction in which the valve opening lift of the engine valve increases from the second arc line drawn through the center point of the control eccentric cam when controlled to the minimum operating angle with the drive shaft as the center A variable valve operating apparatus for an internal combustion engine, characterized in that The variable valve operating apparatus for an internal combustion engine according to claim 1,
The transmission mechanism is configured to open the engine valve by pulling up the end of the swing cam opposite to the cam nose portion,
A line segment connecting the second fulcrum and the third fulcrum and a line segment connecting the first fulcrum and the second fulcrum at the moment when the engine valve reaches the valve opening peak lift controlled to the predetermined intermediate operating angle. A variable valve operating apparatus for an internal combustion engine, characterized in that the angle is smaller than the angle formed by the two line segments at the moment when the valve opening peak lift of the engine valve is controlled to the minimum operating angle. The variable valve operating apparatus for an internal combustion engine according to claim 1 or 2,
The position of the control eccentric cam when controlled to a predetermined large operating angle larger than the predetermined intermediate operating angle is greater than the position of the control eccentric cam when controlled to the predetermined intermediate operating angle. 2. A variable valve operating apparatus for an internal combustion engine, characterized in that it is close to two circular arc lines. The variable valve operating apparatus for an internal combustion engine according to claim 1,
The transmission mechanism is configured to open the engine valve by pushing down an end of the swing cam on the cam nose side.
An angle formed by a line segment connecting the second fulcrum and the third fulcrum and a line segment connecting the first fulcrum and the second fulcrum at the moment when the engine valve reaches the valve opening peak lift under the predetermined intermediate operating angle. Is greater than the angle formed by the two line segments at the moment when the engine valve reaches the peak lift when controlled to the minimum operating angle. A drive shaft that is fixed to the drive support shaft and has a raindrop-like drive cam that protrudes radially outward, and that rotates in synchronization with the crankshaft around the drive support shaft;
A control shaft, and a control eccentric cam provided with a control point eccentrically provided with respect to the axis of the control support shaft, the control shaft provided rotatably about the control support shaft;
A swing cam that is swingably supported by the drive support shaft and swings about the drive support shaft to open and close the engine valve by a cam surface;
A rocker arm that receives a rotational force from the drive cam via a second fulcrum and swings with the control eccentric cam as a fulcrum;
A link rod whose one end is linked to the rocker arm so as to be swingable around a third fulcrum between the rocker arm and whose other end is linked to the swing cam;
With
A variable valve operating apparatus for an internal combustion engine that changes at least an operating angle of an engine valve by rotating the control shaft,
The position of the control eccentric cam when controlled to a predetermined intermediate operating angle larger by a predetermined amount than the minimum operating angle of the engine valve,
The rotation of the drive shaft is more than the first arc line passing through the center point of the control eccentric cam drawn around the second fulcrum at the moment when the valve opening peak lift of the engine valve controlled to the minimum operating angle is reached. Set it to be the advance position as seen from the direction,
A position that deviates in a direction in which the valve opening lift of the engine valve increases from the second arc line drawn through the center point of the control eccentric cam when controlled to the minimum operating angle about the drive support shaft A variable valve operating apparatus for an internal combustion engine, characterized in that

Images