JPH0734821A - Intake/exhaust valve drive control device of internal combustion engine - Google Patents

Abstract

PURPOSE:To prevent the generation of irregular motions such as jumping of an intake exhaust valves, and secure the highly precise control of the valve timing. CONSTITUTION:A disk housing 34 which is provided between a driving shaft 21 and a cam shaft 22 and is movable in the radial direction through a moving means, and a disk 29 which is rotatably held in a supporting hole of the disk housing 34 and whose center (Y) is eccentrically moved in the direction of the axis (X) of the driving shaft 21 as the disk housing 34 is moved are provided. The moving means consists of a first eccentric cam 41 and a second eccentric cam 43 provided on each end part of the disk housing 34, and the rotational directions of the respective eccentric cams 41, 43 are provided so as to be opposite to each other to make the locus of the center movement of the disk 29 linear.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an intake / exhaust valve drive control device for variably controlling the opening / closing timing of intake / exhaust valves according to the operating state of an internal combustion engine.

[0002]

2. Description of the Related Art Various conventional devices of this kind have been provided, and one of them is described, for example, in Japanese Patent Application No. 4-172665 filed by the present applicant.

The outline will be described with reference to FIG. 14. A drive shaft 1 to which a rotational force is transmitted from a crank shaft of an engine via a sprocket, and a cylinder which is provided on the outer periphery of the drive shaft 1 so as to be rotatable relative to each other. A plurality of cam shafts 2 formed separately for each drive shaft, and the drive shaft 1 disposed between the cam shafts 2.
A plurality of annular disc housings 3 provided so as to be swingable substantially in the radial direction with respect to the axis X of the discs, and rotatably supported in the inner peripheral support holes 4 of each disc housing 3, and the drive shaft 1 and the cam. The shaft 2 is connected to the shaft 2 via a pair of pins 10 and 11, and the center of the disk Y is provided with a disk 5 that is eccentrically moved with the axis X of the drive shaft 1 as the disk housing 3 swings.

The camshaft 2 is integrally provided with a pair of cams 2a for opening and operating two intake valves per cylinder on the outer circumference against the spring force of a valve spring.

The disk housing 3 has a first eccentric cam 6 rotatably provided in a first cam hole 3a at one end thereof, and a second eccentric cam 3b in a second cam hole 3b at the other end thereof. 7 is rotatably provided. The first eccentric cam 6 has a support shaft 8 whose one end is held by a cylinder head (not shown).
While being rotatably supported by the second eccentric cam 7, a control shaft 9 to which a rotational force is applied from a hydraulic actuator is connected to the second eccentric cam 7.

When the control shaft 9 is rotated by a predetermined angle by the hydraulic actuator as the engine operating condition changes, the second eccentric cam 7 rotates in one direction within a predetermined angle range. Following this, the first eccentric cam 6 also rotates in the same direction within a predetermined angle range. Therefore, each disc housing 3 swings in a substantially radial direction with respect to the axis X of the drive shaft 1 with the first eccentric cam 6 as a swing fulcrum, and accordingly, the disc 5 also swings. The center Y is the drive shaft 1.
It is eccentric from the axis X of (Fig. 14).

Therefore, the rotation phase of the disk 5 changes with respect to the drive shaft 1 for each rotation of the drive shaft 1, and at the same time, the rotation phase of the cam 2a integrally provided on the outer periphery of the cam shaft 2 with respect to the disk 5. Change. Therefore, the cam 2a rotates with respect to the drive shaft 1 with a phase difference twice the phase difference with respect to the drive shaft 1 of the disk 5. As a result, the valve timing can be made variable according to the phase difference of the cam.

Further, since the disc housing 3 is swung by the first and second eccentric cams 6 and 7,
It is possible to prevent the generation of hammering noise and wear due to the alternating load of the disc housing 3 caused by the fluctuation of the rotational torque of the camshaft 2, and to determine the size and relative mounting position of both eccentric cams 6 and 7 and the eccentric amount of the disc 5. It is possible to freely set the position according to the initial eccentric position and the like, so that the degree of freedom in layout is improved and the device can be made compact.

[0009]

By the way, in the invention according to the above-mentioned prior application, the first and second eccentric cams 6, 7 rotate in the same direction as described above. That is,
When the second eccentric cam 7 rotates counterclockwise about the axis Q2 of the control shaft 9 as indicated by the arrow in the figure due to the rotation of the control shaft 9, the first eccentric cam 6 also rotates the axis Q1 of the support shaft 8.
Rotate in the same direction as indicated by an arrow around the center of the arrow, and the movement loci of the centers P1 and P2 of both eccentric cams 6 and 7 are PA-PB-PC.
As shown in the drawing, the shapes of the arcs are almost the same. Therefore, the disc housing 3, that is, the disc 5 has a movement locus from the concentric position where the center Y of the disc housing 3 coincides with the axial center X of the drive shaft 1 to the eccentric position, or in the opposite direction, Y1-Y2-.
It becomes an arc like Y3.

On the other hand, the cam lift waveform characteristic (valve operating angle characteristic) of the cam 2a is fixed at the maximum lift position (point P) as shown in FIG. 15B when the profile of the cam 2a is symmetrical. The point P always coincides with the position where the phase difference between the drive shaft 1 and the camshaft 2 is zero (0), and the cam lift waveform N (solid line) of the maximum working angle and the cam lift waveform M (of the minimum working angle) are shown. (Solid line) and the cam lift waveform L (broken line) while the center Y of the disk 5 is eccentrically moving
Also has a symmetrical shape.

However, since the moving locus of the disk 5 is arcuate as described above, while the center Y of the disk 5 is eccentrically moving with respect to the axis X of the drive shaft 1, the drive shaft 1 is not moved. 15A, the rotational phase difference between the camshaft 2 and the camshaft 2 has a relatively small waveform characteristic, as shown by the alternate long and short dash line in FIG. 15A, and the intermediate phase difference also does not pass through the 0 position. Therefore, the cam lift waveform of the cam 2a is also the same as the maximum operating angle and the minimum operating angle when the maximum eccentric position is reached as shown in FIG. 15B, and the maximum lift point (point P) is also the same position. However, during the movement in the concentric direction or the eccentric direction, the cam lift waveform changes from the reference waveform (broken line) as shown by the one-dot chain line in FIG. 15B as the rotational phase difference between the drive shaft 1 and the cam shaft 2 changes. It will shift. Therefore, the maximum lift point PX is displaced from the point P, and the cam lift waveform also becomes asymmetrical, and the downward side Z1
Is steeper than the uphill side Z2.

In this way, the downward side Z1 of the cam lift waveform
If the engine becomes a steep slope, the intake / exhaust valve may cause irregular movements such as jumping or bouncing, especially when the engine is rapidly accelerated from the low speed range (minimum operating angle state) to the high speed range. Therefore, the control accuracy of the intake / exhaust valve is significantly reduced.

[0013]

The present invention has been devised in view of the problems of the device according to the above-mentioned prior application, and it is a drive shaft to which a rotational force is transmitted from an engine and a coaxial shaft of the drive shaft. A cam shaft which is provided on the upper surface so as to be rotatable relative to the outer surface and has a cam for opening and closing the intake and exhaust valves; and a disk housing which is provided to be movable in a substantially radial direction with respect to the axis of the drive shaft. A disc that is rotatably supported in a support hole of the disc housing, and that links the drive shaft and the cam shaft and whose center eccentrically moves with the axial center of the drive shaft as the disc housing moves; In an intake / exhaust valve drive control device including a moving means for moving in a predetermined direction, the center movement locus of the disk is set to be substantially linear through the disk housing and the moving means. That.

[0014]

By making the center movement locus of the disk not substantially arcuate as in the prior application, but almost always linear, the center of the disk moves from the concentric position where it coincides with the axis of the drive shaft to the maximum eccentric position. The cam lift waveform characteristic during control is
The maximum lift point is always in the same position, and it is symmetrical. Therefore, the behavior of the intake and exhaust valves is stable, and even if the engine operating state immediately shifts from the low speed region to the high speed region, the occurrence of jumping or the like is prevented.

[0015]

1 to 8 show an embodiment in which the intake / exhaust valve drive control device according to the inventions of claims 1 and 2 is applied to the intake side. Reference numeral 21 in FIG. 1 indicates a crankshaft of an engine not shown. The drive shaft 22 to which the rotational force is transmitted via the sprocket is a hollow cam shaft which is arranged on the outer periphery of the drive shaft 21 with a constant gap and is coaxial with the center X of the drive shaft 21. The drive shaft 21 extends in the front-rear direction of the engine and is formed in an inner hollow shape for weight reduction.

The cam shaft 22 is rotatably supported by a cam bracket 20a provided at the upper end of the cylinder head 20, and as shown in FIGS. 1 to 4, an intake valve 23 and a valve spring 24 are provided at predetermined positions on the outer circumference. A plurality of cams 26 ... Which are opened against the spring force of the valve lifter 25 via the valve lifter 25 are integrally provided. Further, the camshaft 22 is divided and formed from a direction perpendicular to the axis at a predetermined position in the longitudinal direction, and a flange portion 27 is provided on one divided end portion. A sleeve 28 and an annular disc 29 are arranged between the divided ends. As shown in FIG. 5, the flange portion 27 is formed with a slender rectangular engagement groove 30 extending from the hollow portion in the radial direction, and one of the annular discs 29 is circumferentially formed on the outer peripheral surface thereof. A protruding surface 27a that is in sliding contact with the side surface is integrally provided.

The sleeve 28 has a small diameter one end portion 28b.
Is rotatably inserted into the other end of the camshaft 22 on the other side, and is fixedly connected to the drive shaft 21 via a connecting shaft 31 penetrating diametrically at a substantially central position. Further, as shown in FIG. 6, the flange portion 32 provided at the other end of the sleeve 28 has an elongated rectangular engaging groove 33 formed in the radial direction on the side opposite to the engaging groove 30. At the same time, the outer peripheral surface is integrally provided with a protruding surface 28a that is in sliding contact with the other side surface of the annular disk 29.

The annular disc 29 has a substantially donut plate shape, an inner diameter thereof is substantially the same as the inner diameter of the camshaft 22, and an annular clearance S is formed between the annular disc 29 and the outer peripheral surface of the drive shaft 21. In addition, the narrow outer peripheral portion 29a is rotatably supported on the inner peripheral surface of the support hole 34a provided at the center of the annular disc housing 34 via the metallic annular bearing member 35. Further, in the pin holes 29b and 29c penetratingly formed at the opposite positions on the diameter line, the engagement grooves 30 and
A pair of pins 36 and 37 that engage with 33 are provided. The pins 36 and 37 project in opposite directions to each other in the axial direction of the camshaft, and the base portions thereof have pin holes 29b and 29b.
It is rotatably supported in c, and abuts against opposite inner surfaces 30a, 30b, 33a, 33b of the engaging grooves 30, 33 on both side edges of the tip portion as shown in FIGS.
Plane portions 36a, 36b, 37a, 37b having a width of face are formed.

As shown in FIGS. 1 and 2, the disk housing 34 has a substantially annular shape, and the first cam hole 38 is formed on one side of the boss portions 34b and 34c on both sides of the upper end of the outer circumference.
Is penetratingly formed in the axial direction of the camshaft 22, and the second cam hole 39 is penetratingly formed on the other side. A first eccentric cam 41, which is a moving means supported by a support shaft 40, is rotatably provided in the first cam hole 38, while a drive to be described later is provided in the second cam hole 39. A second eccentric cam 43 fixed to the control shaft 42 of the mechanism 45 via a fixing hole 43a is rotatably provided.
Therefore, the disc housing 34 is swingably supported by the support shaft 40 via the first eccentric cam 41, and is swung by the second eccentric cam 43.

More specifically, as shown in FIG. 3, the support shaft 40 is press-fitted and fixed in a fixing hole 44a of a bracket 44 whose base is fixed to the upper end of the cylinder head 20. The tip portion is slidably inserted into the insertion hole 41d of the first eccentric cam 41 to rotatably support the first eccentric cam 41.

The first eccentric cam 41 has a ring shape as shown in FIGS. 1 to 3, the outer diameter thereof is set to be slightly smaller than the inner diameter of the first cam hole 38, and the wall thickness in the circumferential direction is set. Is gradually changed so that the portion facing the thin portion 41b becomes the maximum thick portion 41c. Further, the center P1 thereof is deviated from the axis Q1 of the support shaft 40 by a predetermined amount ε1. The first eccentric cam 41 is adapted to be prevented from slipping out of the support shaft 40 by a snap ring 60 fitted to the outer periphery of the tip end portion of the support shaft 40.

Further, the second eccentric cam 43 is set to have a smaller diameter than the first eccentric cam 41, and its rotational position is also the same, and its center P2 is the center Q2 of the control shaft 42. Is deviated by a predetermined amount ε2, which is the same as the deviation amount ε1 of the first eccentric cam 41. Further, the first eccentric cam 41 and the second eccentric cam 43 are adapted to rotate in mutually opposite directions. That is, the second eccentric cam 43
Is rotated counterclockwise by the control shaft 42 as indicated by an arrow in the figure, the first eccentric cam 41 is set to follow the counterclockwise rotation via the support shaft 40.

As shown in FIGS. 7 and 8, the drive mechanism 45 includes the control shaft 42, a hydraulic actuator 46 provided at one end of the control shaft 42, and a hydraulic pressure for supplying / discharging hydraulic pressure to / from the hydraulic actuator 46. And a circuit 47. The control shaft 42 extends in the front-rear direction of the engine in parallel with the support shaft 40, and a predetermined portion thereof is supported by a bearing (not shown) on the cylinder head 20.

The hydraulic actuator 46 has a cylindrical housing 48 fixed to the cylinder head 20 via a bracket 61, a two-vane rotary vane 49 rotatably provided in the cylindrical housing 48, Each of the first oil chambers 5 which are separated by the rotary vanes 49 and are diagonally located
0, 50 and second oil chambers 51, 51, and the rotary vane 49 is connected to the control shaft 42.

The hydraulic circuit 47 includes the first and second oil chambers 5
A pair of first and second oil passages 52 for supplying and discharging hydraulic pressure to and from 0, 51
a, 52b, a 4-port 2-position electromagnetic switching valve 53 provided at the ends of the oil passages 52a, 52b, and an oil pump 5 provided at the upstream end of the oil main gallery 54.
5, a drain passage 57 that appropriately communicates with the oil passages 52a and 52b to return the working oil into the oil pan 56, and a relief valve 58 that controls the pump discharge pressure to a constant pressure.

Further, the electromagnetic switching valve 53 is switched by an ON-OFF signal from the controller 59 which detects the current engine operating state based on signals such as the engine speed and the intake air amount, and the OFF signal causes the oil to change. The pump 55 and the first oil passage 52a are communicated with each other, the second oil passage 52b and the drain passage 57 are communicated with each other, and an ON signal communicates with the opposite.

The operation of this embodiment will be described below.
First, when the engine speed is low and the load is low, an ON signal is output from the controller 59 to the electromagnetic switching valve 53 and the oil pump 55
The hydraulic pressure discharged from the first oil chambers 50, 50 flows into the first oil chambers 50, 50, while the hydraulic oil in the second oil chambers 51, 51 flows into the drain passage 57.
Is discharged into the oil pan 56. For this reason, the rotary vane 49 rotates counterclockwise in the drawing to rotate the control shaft 42.
Rotate in the same direction. Therefore, the second eccentric cam 43
2 rotates counterclockwise in the drawing from the position shown in FIG. 1 to the θ1 angle position, and the maximum thick portion 43c moves from the left side to the right side in the drawing.

Accordingly, the disc housing 34 has the first
Through the cam hole 38 and the first eccentric cam 41, the support shaft 40 is used as a fulcrum to linearly move in the horizontal direction by the amounts of ε1 and ε2, and the center Y of the annular disc 29 is the axis of the drive shaft 21 (cam shaft 22). Eccentric from heart X. That is, as the second eccentric cam 43 rotates, the first eccentric cam 41 follows and rotates in the opposite direction, and the center Y of the annular disc 29 moves from the axis X of the drive shaft 21 to the right in the figure by a predetermined amount E. Only eccentric in a straight line.
Therefore, the sliding positions of the engagement groove 33 and the pin 37 on the sleeve 28 side and the engagement groove 30 and the pin 36 on the cam shaft 21 side move for each rotation of the drive shaft 21, and the angular velocity of the annular disc 29 changes. Then, unequal angular velocity rotation occurs.

That is, when the sliding position of the locking groove 30 and the pin 36 approaches the axis X of the drive shaft 21, the sliding position of the locking groove 33 and the pin 37 moves away from the axis X. . In this case, the annular disc 29 has a large angular velocity with respect to the drive shaft 21, and the angular velocity of the camshaft 22 also becomes large with respect to the annular disc 29. Therefore, the camshaft 22 is partially doubled in speed with respect to the drive shaft 21.

On the other hand, when the engine shifts to the high speed and high load range, the controller 59 outputs an OFF signal to the electromagnetic switching valve 53, and the working oil in the first oil chambers 50, 50 is discharged from the drain passage 57. At the same time, the oil pressure is sent from the oil pump 55 into the second oil chambers 51, 51, and the rotating vanes 4
9 turns in the clockwise direction. Therefore, the second eccentric cam 43 rotates clockwise while the first eccentric cam 41 rotates.
Follows this and rotates counterclockwise to return to the original position shown in FIG. As a result, the disc housing 3
4 also moves linearly horizontally to the original position through the counterclockwise rotation of the first eccentric cam 41, and the center Y of the annular disc 29 is moved.
Coincides with the axis X of the drive shaft 21.

Therefore, in this case, no rotational phase is generated between the annular disc 29 and the drive shaft 21, and the center of the camshaft 22 and the center Y of the annular disc 29 are also coincident with each other. The rotational phase difference between 29 does not occur either. Therefore, as the drive shaft 21 rotates, the sleeve 28 rotates synchronously via the connecting shaft 31, and the locking groove 33 on the sleeve side and the pin 37, the annular disc 29, the pin 36, and the locking groove 30 on the cam shaft 22 side. Through camshaft 22
Also rotates synchronously.

As a result, the camshaft 22 and the cam 26 and the drive shaft 21 are based on the changes in the respective angular velocities as described above.
9A, the valve timing changes according to the phase difference of the camshaft 22 with the valve lift kept constant as shown in FIG. 9A.

That is, when the angular velocity of the cam shaft 22 is relatively large, the rotational phase with respect to the drive shaft 21 is 2
Proceed until 1 and 22 become constant speed, and eventually camshaft 2
When the angular velocity of 2 becomes relatively small, the rotational phase becomes 2
Delay until 1 and 22 become constant speed. Then, as shown in FIG. 9A, the same phase point (point P) exists in the middle of the maximum and minimum points of the rotational phase difference, and the change in the rotational phase shown by the broken line in FIG. The valve opening timing of 23 is delayed, the valve closing timing after point P is advanced, and the operating angle of the valve is reduced as shown by the broken line in FIG. 9B. Therefore, in the engine low speed and low load region as described above, the operating angle of the intake valve 23 becomes small as shown by the broken line in FIG. 9B, the opening timing is slightly delayed, and the closing timing is advanced. As a result, the valve overlap of the intake and exhaust valves is reduced, the residual gas in the combustion chamber is reduced, and stable combustion improves fuel efficiency. Further, the early closing timing improves the intake charging efficiency and can increase the low speed torque.

On the other hand, in the high speed and high load region, the operating angle becomes large as shown by the solid line in FIG. 9B, the opening timing is advanced and the closing timing is delayed, so the intake charging efficiency utilizing the intake inertial force is improved. However, high output can be achieved. In such a high speed and high load range, the eccentric cam 43 is further rotated clockwise so that the disc housing 34 and the annular disc 29 are rotated.
Is moved to the maximum rightward direction, the operating angle of the intake valve 23 is further increased as shown by the alternate long and short dash line in FIG. 9B, and it is possible to promote higher output.

As described above, in this embodiment, the disc housing 3 is constituted by the first eccentric cam 41 and the second eccentric cam 43.
Since 4 is moved, it is of course possible to prevent the generation of hammering noise and abrasion due to the alternating load of the disk housing 34 due to the fluctuation of the rotational torque of the cam shaft 22, and in particular, to make the eccentric cams 41 and 43 reverse to each other. Direction, the disc housing 34 and the annular disc 29 are linearly moved in the horizontal direction to move the center Y of the annular disc 29 from the axis X of the drive shaft 21 to the eccentric or concentric position. The cam lift waveform (operating angle) of the cam 26 during the conversion from the concentric position to the maximum eccentric position or from the maximum eccentric position to the concentric position is always symmetrical as shown in FIG. 9B.

Therefore, the maximum valve operating angle change is always obtained with respect to the eccentricity of the disk 29, and highly accurate valve timing control can be secured.

Further, due to the linear movement of the disk 29, jumping or bouncing of the intake valve is achieved even when the valve is moved to the high speed range by performing rapid acceleration or the like during the small operating angle control of the valve in the low speed range or the like. The occurrence of irregular movement of the is sufficiently prevented. As a result, highly accurate control of intake air becomes possible.

Further, since the disk housing 34 is supported by the two eccentric cams 41 and 43 as described above, the size and relative mounting position of the both eccentric cams 41 and 43 are eccentric to the annular disk 29. It is possible to freely set it depending on the initial eccentric position and the rotation direction.
For this reason, the degree of freedom in layout is improved, and the device can be made compact. Moreover, both eccentric cams 41, 4
Since the disk housing 34 or the annular disk 29 and the drive shaft 21 are manufactured, the positioning and so-called centering work during the manufacturing process become extremely easy.

10 and 11 show an embodiment according to the invention of claims 1 and 3, wherein the moving means of the disk housing 34 is formed by a pair of links. That is, in the annular disk housing 34, the housing shafts 62 and 63 are axially fixed to both end projections 34a and 34b on the substantially diameter line, and the housing shaft 6 is
Each of the first ends 64a and 65a of the first link 64 on the driven side and the second link 65 on the drive side are rotatably supported via the pivot holes. Both links 64 and 65 are
The disk housings 34 are arranged on both ends of the disk housing 34 in parallel along a substantially tangential direction, and are arranged upside down. Further, the other end 64b of the first link 64 is rotatably supported by a support shaft 66 fixed to the cylinder head through an insertion hole, while the other end 65b of the second link 65 is provided.
Is connected to the control shaft 67 of the drive mechanism 45 through a fixing hole. Then, the first link 64 and the second
The links 65 are provided so as to rotate in directions opposite to each other around the control shaft 67 and the support shaft 66, respectively, as indicated by arrows in the figure.

Therefore, in this embodiment, in the engine high speed and high load region, both links 64 and 65 are held in positions swinging to the left as shown by the broken line in FIG. The axis X of 21 is concentric, and the valve operating angle is largely controlled as described above.

On the other hand, when the engine speed is shifted to the low speed and low load region, the control shaft 67 is rotated clockwise by the hydraulic actuator 46 to rotate the second link 65 clockwise (arrow), and the angle indicated by the solid line is shown. Hold in position. Therefore, the first link 64 also rotates in the counterclockwise direction (arrow) in the drawing about the support shaft 66 and is held at the same angular position. Therefore, the disc housing 34 linearly moves in the horizontal direction as shown in the drawing, and the disc 29 also linearly moves so that the center Y is eccentric from the axis X of the drive shaft 21.

Therefore, also in this embodiment, since the disk 29 moves linearly, the same effect as that of the above embodiment can be obtained. Further, in this embodiment, since the pair of links 64 and 65 are simply used, the structure is simplified, the manufacturing work efficiency is improved, and the cost is reduced.

12 to 13 show an embodiment according to the invention of claims 1 and 4, wherein the moving means is a disk housing 34.
Is formed integrally with one end side of the movable member 70 and a rotating member 71 that is inserted through the movable member 70 to move the movable member 70 in the vertical direction.

More specifically, the movable member 70 has a substantially rectangular shape that is long in the vertical direction, and an internal thread portion 72 is formed on the inner peripheral surface of a through hole that is formed through the internal vertical direction.

The rotating member 71 is in the shape of a bolt, the lower end 71a is axially supported in the support groove 20a on the upper surface of the cylinder head 20, and the upper end 71b is a bearing of a bracket 73 fixed to the cylinder head 20. The whole is rotatably supported in the hole 73a via a flange portion 71c. Further, a spiral male screw portion 74 screwed into the female screw portion 72 is formed on the entire outer peripheral surface from the flange portion 71c to the lower end portion 71a. Further, the rotating member 71 is provided with the drive mechanism 4 connected to the upper end portion 71b.
The forward and reverse rotation control is performed by 5.

The drive mechanism 45 is provided on the upper end portion 71b of the rotating member 71 and is in mesh with each other.
5, 76, a control shaft 78 having one end connected to the bevel gear 76 on one side, and a rotary stepping motor (not shown) connected to the other end of the control shaft 78. The bevel gear 75 on the other side is fixed to the upper end portion 71b of the rotating member 71. Further, the stepping motor is configured to drive forward and reverse rotation based on a pulse control signal output from the control unit,
The control unit has a built-in microcomputer that detects a current engine operating state based on information signals from various sensors such as a crank angle sensor, an air flow meter, and an engine cooling water temperature sensor, and outputs a pulse signal. is doing.

Therefore, according to this embodiment, when the control shaft 78 is rotated in one direction by the stepping motor at the time of high speed and high load of the engine, both bevel gears 75, 7 are driven.
6 rotate with each other to rotate the rotating member 71 in one direction. As a result, the movable member 70 has the female and male screw portions 72,
As shown in FIG. 12, it linearly slides via 74 to the maximum upper position. Therefore, the disc housing 3
4, the movable member 70 linearly moves upward in parallel, and the center Y of the disk 29 is located concentrically with the axis X of the drive shaft 21.

On the other hand, when shifting to the low speed and low load region, the control shaft 78 rotates in the reverse direction, so that both bevel gears 75 and 76 are rotated.
The rotating member 71 rotates in the reverse direction via. Therefore, the movable member 70 is, as shown in FIG.
Linearly slides to the maximum downward position, and the disk housing 34 also linearly moves downward. As a result, the center Y of the disk 29 is aligned with the axis X of the drive shaft 21.
Decenters a predetermined amount e from below.

Therefore, in this embodiment as well, the same operational effects as those of the above-described respective embodiments can be obtained, and the above-mentioned alternating load transmitted from the disk housing 34 to the movable member 70 is obtained by the female and male screw portions 72. , 74, it is absorbed when the linear motion is converted to the rotary motion. Therefore, the transmission of the alternating load to the stepping motor is reliably cut off, and the increase of the rotational driving load is prevented.

[0050]

As is apparent from the above description, according to the present invention, since each moving means can eccentrically move the disk through the disk housing in a straight line shape instead of an arc shape, the waveform of the cam lift is changed. It is possible to always have a symmetrical shape. Therefore, the maximum valve operating angle change is always obtained with respect to the eccentricity of the disk, and the behavior of the intake / exhaust valve can be stabilized even when the operating angle shifts to the high rotation range with a small operating angle, and jumping, bouncing, etc. The irregular movement of is prevented.

Further, due to the linear eccentric movement of the disk,
Highly accurate control of the valve operating angle can be obtained.

[Brief description of drawings]

1 is an AA of FIG. 3 showing an embodiment of the invention of claim 2;
FIG.

FIG. 2 is a sectional view taken along the line AA of FIG. 3 showing the operation of this embodiment.

FIG. 3 is a partial vertical cross-sectional view showing a main part of this embodiment.

FIG. 4 is a plan view showing a main part of this embodiment.

5 is a cross-sectional view taken along the line BB of FIG.

FIG. 6 is a sectional view taken along line CC of FIG.

FIG. 7 is a schematic view showing a drive mechanism used in this embodiment.

FIG. 8 is a plan view of a main part of the drive mechanism.

FIG. 9 is a characteristic diagram of the rotational phase difference between the drive shaft and the cam shaft and the valve timing according to the present embodiment.

FIG. 10 is a sectional view of an essential part showing an embodiment of the invention of claim 3;

FIG. 11 is a plan view of a main part of this embodiment.

FIG. 12 is a front view of a main part showing an embodiment of the invention of claim 4;

FIG. 13 is a front view of the main part showing the operation of the embodiment.

FIG. 14 is a cross-sectional view of a main part of the device according to the prior application.

FIG. 15 is a characteristic diagram of a rotational phase difference between a drive shaft and a cam shaft and valve timing in the device of the prior application.

[Explanation of symbols]

 21 ... Drive shaft 22 ... Cam shaft 23 ... Intake valve 29 ... Annular disc 34 ... Disc housing 34a ... Support hole 41 ... First eccentric cam 43 ... Second eccentric cam 45 ... Drive mechanism 64 ... First link 65 ... Second link 66 ... Spindle 70 ... Movable member 71 ... Rotating member

Claims (4)

[Claims] 1. A drive shaft to which a rotational force is transmitted from an engine,
A cam shaft is provided coaxially with the drive shaft so as to be rotatable relative to the drive shaft, and a cam shaft having a cam for opening and closing an intake / exhaust valve on an outer peripheral surface thereof is provided so as to be movable in a substantially radial direction with respect to an axis of the drive shaft. A disk housing, and a disk rotatably supported in a support hole of the disk housing, the center of which is eccentric with the axis of the drive shaft as the disk housing moves while connecting the drive shaft and the camshaft. An intake / exhaust valve drive control device including a moving means for moving the disk housing in a predetermined direction, wherein a center movement locus of the disk is set to be substantially linear through the disk housing and the moving means. Intake and exhaust valve drive control device for internal combustion engine. 2. A first eccentric cam, which is rotatably provided at one end of the disc housing and supports one end of the disc housing via a support shaft, and is rotated to the other end of the disc housing. A second eccentric cam, which is freely provided and rotationally driven by a drive mechanism to obtain a follow-up rotation of the first eccentric cam to move the disc housing, and the first eccentric cam and the second eccentric cam. 2. The intake / exhaust valve drive control device for an internal combustion engine according to claim 1, wherein the rotation directions of the discs are set to be opposite to each other, and the center movement locus of the disc is set to be substantially linear. 3. A first link, one end of which is rotatably supported at one end in the diametrical direction of the disk housing and the other end of which is rotatably supported via a support shaft, and the other end of the moving means. A second link that is pivotally supported at an end and the other end is connected to a drive mechanism.
2. The internal combustion engine according to claim 1, wherein the links are provided so as to be swingable in mutually opposite directions about a pivot point of each other end, and a center movement locus of the disk is set to be substantially linear. Intake and exhaust valve drive control device. 4. The moving means is formed of a movable member provided at one end of the disk housing along a substantially tangential direction, and a rotating member linked to the movable member and rotationally driven by a drive mechanism, 2. The intake / exhaust valve drive control device for an internal combustion engine according to claim 1, wherein the movable member is linearly moved by the rotation of the rotary member to set the center movement locus of the disk linearly.