JP3355219B2 - Intake and exhaust valve drive control device for internal combustion engine - Google Patents

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 apparatuses of this kind are provided, one of which is, for example, Japanese Utility Model Laid-Open No. 57-198.
No. 306 is known.

[0003] Referring to FIGS. 20 and 21, an outline 2 is provided on the outer periphery of a camshaft 1 so that an intake valve 16 is opened against a spring force of a valve spring 17. The cam 2 is axially positioned by a cam bearing bracket 3 and a flange 5 fixed to the camshaft 1 via a key 4. A U-shaped groove 6 is formed in a flange 7 formed on one side of the cam 2, and a U-shaped groove 8 is formed in the flange 5. An annular disk 9 is interposed between the flange portions 5 and 7.
The disk 9 has the two U-shaped grooves 6 at opposite positions on both sides.
8 are provided with pins 10 and 11
The outer circumference is rotatably supported by the control ring 12. The control ring 12 is swingably supported by a support hole 13 on the cylinder head 18 side via a projection 12a on the outer periphery, and a gear portion 12b provided on the opposite side of the projection 12a pivotally supports the rocker arm 15. It meshes with a gear ring 14 a on the outer periphery of the rocker shaft 14.

The control ring 12 swings in one or the other direction according to the operating state of the engine by a drive mechanism (not shown) via a gear ring 14a meshed with the gear portion 12b. That is, when the center P of the disk 9 is at the position shown in FIG. 20, the rotation centers of the camshaft 1 and the disk 9 coincide with each other. While rotating synchronously
The cam 2 rotates synchronously with the camshaft 1 via the pin 10 and the U-shaped groove 6.

When the rocker shaft 14 is rotated by a hydraulic actuator of the drive mechanism in accordance with a change in the operating state of the engine, the control ring 12 swings about the projection 12a as a fulcrum via the gear ring 14a and the gear portion 12b. As a result, the center P of the disk 9 is eccentric in the rotation direction with respect to the center of the camshaft 1. Therefore, the pins 10, 11 move along the U-shaped grooves 6, 8, respectively, and rotate the flange portions 5, 7 about the camshaft 1 in the eccentric direction. Therefore, every time the camshaft 1 rotates, the rotation phase of the disk 9 changes with respect to the camshaft 1, and at the same time, the rotation phase of the cam 2 also changes with respect to the disk 9. Therefore, the cam 2 rotates with respect to the camshaft 1 with a phase difference of twice the phase difference of the disc 9 with respect to the camshaft 1. As a result, the valve timing can be made variable according to the phase difference of the cam 2.

[0006]

However, in the conventional apparatus, the control ring 12 is connected to the gear portion 12b and the gear ring 1b.
4a, the alternating load acting on the control ring 12 due to the positive and negative rotational torque fluctuations generated in the camshaft 1 during operation, that is, the cyclic load in the forward and reverse rotation directions, A tapping sound is generated between the gear portion 12b and the gear ring 14a, and both
Abrasion occurs with time between 14a and the swing of the control ring 12 becomes unstable. As a result, the accuracy of variable control of the valve timing is reduced.

In order to assemble such an apparatus, an assembling unit of the camshaft 1 on which the cam 2, the disk 9, the control ring 12, and the like are assembled, and a rocker shaft 14 also serving as a control shaft are attached to the cylinder head 18. To be assembled separately. For this reason, when assembling to the cylinder head 18, the gear portion 12 b of the control ring 12 must be engaged with the gear ring 14 a of the rocker shaft 14 at an optimum position. As a result, the assembling work becomes complicated, and the work efficiency is reduced.

Moreover, since the assembling unit of the camshaft 1, the rocker arm 15, the rocker shaft 14, and the like are sequentially assembled in accordance with a predetermined assembly specification, it is difficult to obtain the positional accuracy of each component after the assembly. There is a problem.

[0009]

SUMMARY OF THE INVENTION The present invention has been made in view of the above-mentioned conventional problems, and the invention according to claim 1 is provided at a position above a cylinder head along the engine front-rear direction. A drive shaft, a camshaft provided coaxially with the drive shaft so as to be relatively rotatable, and having a cam on an outer periphery for operating an intake valve or an exhaust valve; and a drive shaft connecting the drive shaft and the camshaft. An intake / exhaust valve having a control mechanism for changing the angular velocity between the drive shaft and the camshaft by displacing with respect to the axis of the shaft, and a drive mechanism for controlling the displacement of the control mechanism via the control shaft in accordance with the engine operating state. In the drive control device, at the upper end of the cylinder head, a frame body including a pair of support portions formed along the longitudinal direction of the engine and a cross beam portion connected between the support portions from a right angle direction is provided. , The cross beam Of between the formed bearing groove and the bearing cap attached to the top of the cross beam portion on the upper surface, as well as rotatably supported to said control shaft, said cross beam portion
The camshaft is inserted into the cam bearing groove formed on the lower surface of the camshaft.
By supporting, the whole of each component is unitized,
The camshaft in the unit is a cylinder head
It is characterized that you were supported on the cam bearing formed in the upper end portion of.

According to a second aspect of the present invention, the frame is provided with
Actuator of the drive mechanism for controlling rotation of the control shaft
The feature is that the eta is fixed .

The invention according to claim 3 is characterized in that both support portions of the frame are arranged on both sides of the engine, and a cross beam portion is laid across the intake side and the exhaust side.

[0012]

According to the present invention, when the center of the annular disk coincides with the center of the drive shaft, the camshaft rotates through the annular disk or the like without phase difference in synchronization with the drive shaft. I do.

On the other hand, when the drive mechanism swings the disk housing in one direction due to a change in the operating state of the engine, the center of the annular disk is eccentric with the center of the drive shaft. Accordingly, the sliding positions of the locking groove of the flange portion on the drive shaft side and the one-side pin and the locking groove of the flange portion on the camshaft side and the pin on the other side move for each rotation of the drive shaft. That is, for example, when the sliding position between the engaging groove on the drive shaft side and the pin approaches the center of the drive shaft, the sliding position between the engaging groove on the camshaft side and the pin is separated from the center of the drive shaft. The angular velocity of the annular disk becomes smaller with respect to the drive shaft, and the angular velocity of the camshaft becomes smaller with respect to the annular disk. Therefore,
The camshaft is decelerated twice with respect to the drive shaft, and a desired valve timing can be obtained via the cam by such a deceleration action. When the annular disk is eccentric to the opposite position, the camshaft is doubled in speed with respect to the drive shaft.

[0014]

According to the first aspect of the present invention, in order to assemble the apparatus, the controller is previously set at a position corresponding to each cylinder of the drive shaft.
Assembling the component parts and the cam shaft configuration, the assembled unit, assembled to the frame. Then, if the control shaft is held in the bearing groove and the bearing cap is fixed from above, and the frame body is fixed to the upper end of the cylinder head with bolts, the whole can be easily assembled.

According to the third aspect of the present invention, the frame body is provided on the cylinder head so as to surround the intake side and the exhaust side instead of being individually provided on the intake side and the exhaust side.
Compared with the case where the components are individually provided, the number of parts can be reduced, the assembling property can be improved, and the weight can be reduced.

[0017]

1 to 3 show a first embodiment in which the intake and exhaust valve drive control device according to the first and second aspects of the present invention is applied to a four-cylinder engine.
FIG. 1 shows a drive shaft 21 to which torque is transmitted from a crankshaft of an engine (not shown) via a sprocket.
Reference numeral 2 denotes a camshaft which is arranged at a fixed gap on the outer periphery of the drive shaft 21 and is provided coaxially with the center X of the drive shaft 21, and 45 is fixed to an upper end portion of the cylinder head 43 by a bolt 44, The drive shaft 21 is a frame that holds the camshaft 22 and the like. The drive shaft 21 extends in the front-rear direction of the engine, and is formed to have a hollow inner shape in order to reduce the weight.

The camshaft 22 is formed in a hollow shape, is rotatably supported by a cam bearing (not shown) provided at the upper end of the cylinder head 43, and has an intake valve at a predetermined position on the outer periphery as shown in FIG. A plurality of cams 26 are provided integrally to open the valve 23 via a valve lifter 25 against the spring force of a valve spring 24. The camshaft 22 is divided at a predetermined position in the longitudinal direction from a direction perpendicular to the axis, and a flange 27 is provided at one of the divided ends. Further, a sleeve 28 and an annular disk 29 are arranged between the two divided ends.
As shown in FIG. 5, the flange portion 27 has an elongated rectangular engagement groove 30 formed in the radial direction from the hollow portion, and has an annular disk 2 extending in the circumferential direction of the outer peripheral surface thereof.
9 is integrally provided with a protruding surface 27a that is in sliding contact with one side surface.

As shown in FIGS. 2 to 4, the frame body 45 has a substantially rectangular frame shape surrounding the intake side of the upper end of the cylinder head 43, and is disposed inside the rocker cover 49 so as to extend in the longitudinal direction of the engine. A pair of support portions 45 extended on both sides along
a, 45a, and a plurality of cross beams 45b... erected from the support portions 45a, 45a at right angles. The cross beam portion 45b has a semicircular bearing groove 46 formed on one end side of the upper surface for bearing a control shaft 42, which will be described later, and a camshaft 22 at a substantially central position on the lower surface.
A cam bearing groove 50 is formed as an arc groove for bearing the upper half. In addition, a shaft hole 45c that rotatably supports one end of a bearing 40, which will be described later, is formed at a substantially center position on the other end side of the cross beam portion 45b.

The sleeve 28 has a small diameter end portion 28b.
Are rotatably inserted into the other divided end of the camshaft 22 and are connected and fixed to the drive shaft 21 via a connecting shaft 31 which penetrates in a diametrical direction at a substantially central position. The flange portion 32 provided at the other end portion of the sleeve 28 is the engaging groove 30 and the opposite elongated rectangular engaging groove 33 along the radial direction is formed as shown in FIG. 6 At the same time, a protruding surface 28a that slides on the other side surface of the annular disk 29 is provided integrally on the outer peripheral surface.

The annular disk 29 has a substantially donut shape, and has an inner diameter substantially equal to the inner diameter of the camshaft 22, and an annular gap S is formed between the annular disk 29 and the outer peripheral surface of the drive shaft 21. The small-diameter outer peripheral portion 29a is rotatably supported on the inner peripheral surface 34a of the annular disk housing 34. Further, a pair of pins 36 and 37 that engage with the respective engagement grooves 30 and 33 are provided in the pin holes 29b and 29c formed to penetrate at opposing positions on the diameter line. The pins 36 and 37 project in opposite directions to each other in the camshaft axial direction, and have their bases rotatably supported in the pin holes 29b and 29c. As shown in FIG.
Two plane-width flat portions 36a, 36b, 37a, and 37b that are in contact with 0a, 30b, 33a, and 33b are formed.

As shown in FIG. 2, the disk housing 34 has a substantially annular shape, and a substantially U-shaped support groove 38 is formed at an outer edge of one end of a boss 35 provided at the upper end of the outer periphery. A cam hole 39 is formed through the other end of the boss 35. One end of the disk housing 34 is rotatably and slidably supported by a support shaft 40 inserted into the support groove 38, and is rotated by an eccentric cam 41 inserted into the cam hole 39. The disk housing 34 swings.

As shown in FIG. 3, the support shaft 40 extends in the front-rear direction of the engine, is rotatably inserted into and supported by a shaft hole 45c, and has both end edges of a portion corresponding to the disk housing 34. The flat contact surfaces 40a, 40b are formed on the support groove 38, and the contact surfaces 40a, 40b are in contact with the opposing surfaces 38a, 38b of the support groove 38 in a surface contact state. And
In the present embodiment, each of the flange portions 27 and 32 is
Annular disk 29, disk housing 34 and spindle 4
0 constitutes a control mechanism.

The eccentric cam 41 has a ring shape, an outer diameter of which is set slightly smaller than an inner diameter of the cam hole 39, and a wall thickness in the circumferential direction from the thin part 41a to the gradually thick part 41.
b. Further, it is fixedly supported by a hollow control shaft 42 through a through hole 41c formed through in the axial direction. As shown in FIGS. 1 and 3, the control shaft 42 extends in the front-rear direction of the engine, and is provided with a bolt 4 in a bearing groove 46 of the cross beam portion 45 b and an upper portion of the frame 45.
8 and bearing cap 47 fixed thereto. The rotation of the control shaft 42 is controlled by a drive mechanism 51.

As shown in FIG. 7, the drive mechanism 51 includes a hydraulic actuator 52 provided at one end of the control shaft 42, and a hydraulic circuit 53 for supplying and discharging hydraulic pressure to and from the hydraulic actuator 52. As shown in FIG. 3 , the hydraulic actuator 52 is provided at one end of the frame 45.
It is fixed to the wall 45d, and 2
A rotary vane 55 of a single blade is rotatably provided while separating the first oil chambers 56 and 56 and the second oil chambers 57 and 57 located on diagonal lines, and the rotary vane 55 is provided with a control shaft. 42. The hydraulic circuit 53 includes:
A pair of first and second oil passages 58a and 58b for supplying and discharging hydraulic pressure to the first and second oil chambers 56 and 57;
A four-port two-position solenoid-operated switching valve 59 provided at an end of the oil pan 58b, an oil pump 61 provided at an upstream end of the oil main gallery 60, and an oil pan 62 which are appropriately communicated with the oil passages 58a and 58b. A drain passage 63 for returning the hydraulic oil to the inside and a relief valve 64 for controlling the pump discharge pressure to a constant pressure are provided. Further, the electromagnetic switching valve 59 is
ON-OF from a controller 65 for detecting a current engine operating state based on signals such as an engine speed and an intake air amount.
The switching operation is performed by the F signal, the oil pump 61 communicates with the first oil passage 58a, and the second oil passage 58b communicates with the drain passage 63 by the OFF signal.
The communication is made in the opposite manner by the N signal.

The operation of this embodiment will be described below.
First, when the engine is at low speed and low load, an ON signal is output from the controller 65 to the electromagnetic switching valve 59 so that the oil pump 61
The hydraulic oil discharged from the first oil chambers 56 flows into the first oil chambers 56, while the hydraulic oil in the second oil chambers 57 flows into the drain passage 63.
From the oil pan 62. As a result, the rotating vane 55 rotates counterclockwise in the drawing to rotate the control shaft 42.
Is rotated in the circumferential direction. Therefore, the eccentric cam 41
As shown in FIG. 8, it rotates counterclockwise from the position (dashed line position) shown in FIG. 2 to the θ angle position, and the thickest portion 41 b moves to the upper side. Therefore, the disk housing 34 is supported by the support shaft 40 via the cam hole 39.
Rocked as a fulcrum, the center Y of the annular disc 29 eccentrically moving from the center X of the drive shaft 21 (the camshaft 22).
That is, when the cam hole 39 side of the boss 35 is pulled up in the upper left direction with the rotation of the eccentric cam 41, the opposing surfaces 38a, 38b of the support groove 38 slide on the contact surfaces 40a, 40b of the support shaft 40, and There is a predetermined amount polarized <br/> heart dynamic swings counterclockwise. Accordingly, the sliding position of the engaging groove 30 and the pin 36 of the engaging groove 33 and the pin 37 and the cam shaft 21 side of the sleeve 28 side is moved for each rotation of the drive shaft 21, the angular velocity of the annular disc 29 is changed The rotation becomes uneven angular velocity.

[0027] That is, if the slide position of the engaging groove 30 and the pin 36 approaches the center X of the drive shaft 21, a relation of sliding positions of the engaging groove 33 and the pin 37 moves away from the center X. In this case, the angular velocity of the annular disk 29 is higher with respect to the drive shaft 21, and the angular velocity of the camshaft 22 is higher with respect to the annular disk 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 / high-load range, the OFF signal is output from the controller 65 to the electromagnetic switching valve 59, and the hydraulic oil in the first oil chambers 56, 56 is discharged from the drain passage 63. At the same time, oil pressure is fed from the oil pump 61 into the second oil chambers 57, 57, and the rotary vanes 5
5 rotates clockwise in reverse. Therefore, the eccentric cam 4
1 rotates clockwise as shown in FIG. 2 and returns to the original position, whereby the disk housing 34 also swings to the original position, and the center Y of the annular disk 29 is
With the center X of Therefore, in this case, no rotational phase occurs between the annular disc 29 and the drive shaft 21 and the center Y of the camshaft 22 and the center Y of the annular disc 29 are also coincident. There is no rotation phase difference. Therefore, as the drive shaft 21 rotates, the connection shaft 31
With the sleeve 28 rotates synchronously via the engagement groove 33 and the pin 37 of the sleeve side, an annular disk 29, pins 3
6, rotating synchronously also the camshaft 22 via the engaging groove 30 of the cam shaft 22 side.

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

That is, when the angular velocity of the camshaft 22 is relatively high, the rotational phase with respect to the drive shaft 21 advances until the speeds of the two shafts 21 and 22 become constant. Phase 2
It is delayed until 1 and 22 become uniform speed. Then, as shown in FIG. 9A, an in-phase point (point P) exists midway between the maximum and minimum points of the rotational phase difference, and in the change of the rotational phase indicated by the broken line in FIG. The valve opening timing of the valve 23 is delayed, the valve closing timing after the 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 low engine speed and low load range as described above, the valve timing of the intake valve 23 becomes small as shown by the broken line in FIG. 9B, and the opening timing is slightly delayed.
The closing time is earlier. This reduces the valve overlap of the intake and exhaust valves, reduces residual gas in the combustion chamber,
Fuel efficiency can be improved by stable combustion. Further, due to the early closing timing, the intake charging efficiency is improved, and the low-speed torque can be increased.

On the other hand, in the high-speed, high-load region, the operating angle is increased as shown by the solid line in FIG. 9B, and the closing period is delayed as well as the same period. And high output can be achieved. In such a high-speed and high-load range, the eccentric cam 41 is further rotated clockwise to move the disk housing 34 and the annular disk 29 of FIG. 8 to the lower right, as shown by the dashed line in FIG. 9B. The operating angle of the intake valve 23 is further increased, which can promote higher output.

As described above, in this embodiment, the valve timing can be variably controlled with high accuracy in accordance with the change in the engine operation. In particular, the eccentricity of the disk housing 34 can be reduced without using gears as in the conventional case. Since the swing is performed by using the cam 41, it is possible to reliably prevent the noise, wear, and the like due to the alternating load of the disk housing 34 due to the fluctuation of the rotational torque of the cam shaft 22.

Further, each pin 36 and 37 on both sides edges flat portion 36a as described above, 36b, 37a, since it is formed in 37b, opposite Naimen 30a of the engaging grooves 30,33,
30b, 33a, and 33b are brought into surface contact with each other. Therefore, when the rotation is transmitted from the drive shaft 21 to the camshaft 22 and when the annular disc 29 is eccentric,
a, 36b, 37a, 37b and opposing inner surfaces 30a, 30
When sliding with b, 33a, 33b, generation of concentrated load between them is prevented, and the surface pressure is reduced. As a result, the engaging groove 3
0, 33 and the pins 36, 37 are prevented from being worn over time, so that the sound of the flanges 27, 32 and the pins 36, 37 is generated due to the fluctuation of the rotational torque of the camshaft 22, and the valves are not affected. A decrease in control accuracy due to a timing shift or the like is prevented.

Further, since the pins 36 and 37 are rotatably supported by the pin holes 29b and 29c of the annular disk 29, the pins 3 and 3 can rotate even when the annular disk 29 swings.
6 and 37 are appropriately rotated to rotate the flat portions 36a, 36b and 37.
a, of 37b with the engaging grooves 30 and 33 facing the inner surface 30a, 30
b, 33a, 33b are always in surface contact. Therefore, occurrence of wear between the two 30, 36, 33, 37 is more reliably prevented.

Moreover, the contact surfaces 40a, 40b of the support shaft 40
Are also formed in a flat shape, and come into contact with the opposing surfaces 38a, 38b of the support groove 38 of the disk housing 34 in a surface contact state, so that the surface pressure is reduced and the occurrence of wear over time is prevented. The free rotation of the support shaft 40 causes the contact surfaces 40a, 4
Since 0b is always in surface contact with the opposing surfaces 38a, 38b, the occurrence of wear and the like is further prevented.

The disk housing 34 does not simply swing about the fulcrum but supports the support groove 3 on the support shaft 40.
Since the oscillating motion is caused by the sliding movement via 8, the amount of eccentricity, that is, the amount of offset of the center Y of the annular disk 29 with respect to the center X of the drive shaft 21 can be increased.

Further, since the frame 45 supports the components such as the control shaft 42 and the support shaft 40, the whole unit including the drive mechanism 51 can be integrated, and the assemblability to the cylinder head 43 can be improved. Becomes extremely good.

That is, in order to assemble the respective components to the cylinder head 43, first, the sleeves 28 are respectively press-fitted into positions corresponding to the respective cylinders of the drive shaft 21 and connected by the connection shaft 31, and then the pins 36, 37 is inserted into the pin holes 29b and 29c of the annular disk 29. Thereafter, the annular disk 29, the disk housing 34, and the camshaft 22 are assembled to the drive shaft 21 in this order. Then, each component is assembled for each cylinder by such a process, and finally a C-ring (not shown) is fitted to the end of the drive shaft 21 to prevent the camshafts 22 from coming off.

The assembly unit is assembled to a frame 45, and the assembly unit of the frame 45 is fixed to the upper end of the cylinder head 43 with bolts 44 while supporting the camshaft 22 with the cam bearing groove 50. The support shaft 40 is previously inserted into each shaft hole 45c of the frame 45, and is fitted into the support groove 38 of the disk housing 34 when assembling the assembly unit such as the drive shaft 21 to the frame 45.

Also, since the cam bearing bracket of the cam shaft 22 and the bearing of the control shaft 42 are shared by the cross beam portion 45b, the number of parts can be reduced and the assemblability can be further improved, and the center of the drive shaft 21 can be improved. X and control shaft 4
Position accuracy with respect to the center Y of the annular disk 29 can be easily obtained through the center of 2. Further, the unitization makes it possible to improve the accuracy of centering and clearance of each component.

FIGS. 10 to 13 show a second embodiment of the present invention, in which the structure of a frame 45 is modified.
The cross beam 45b connected between the shafts 45a has only the bearing groove 46 of the control shaft 42 on the upper surface, and the camshaft 22
Are formed separately from the bearing brackets 66. Also,
As shown in FIG. 13, a large-diameter arc groove 67 for ensuring the loose insertion of the camshaft 22 is formed on the lower surface of the cross beam portion 45b.

Therefore, the control shaft 42 is attached to the frame 45.
And a unit assembled with components such as the eccentric cam 41,
It becomes possible to later assemble the cylinder head 43 on which the camshaft 22 has been previously supported by the bracket 66.
For this reason, the assemblability when the unit of the frame 45 and the engine body are manufactured separately is improved.

FIG. 14 shows a third embodiment of the present invention, in which a support hole 68 is formed at one end of the boss 35 of the disk housing 34 instead of the support groove, and a circle inserted into the support hole 68. While the columnar support shaft 40 is used as a swing fulcrum, the boss 3
5, a substantially U-shaped cam groove 69 is provided instead of the cam hole.
The eccentric cam 41 supported by the control shaft 42 is rotatably slidably provided in the cam groove 69.

Therefore, in this embodiment, the support holes 68
The center of the drive shaft 21 and the center X of the drive shaft 21 are easily aligned, so that the relative positioning of the disk housing 34 with respect to the center X of the camshaft 22 is also facilitated.

FIG. 15 shows a fourth embodiment of the present invention, in which a substantially square frame-shaped spacer 70 made of a wear-resistant material is interposed between a U-shaped cam groove 69 and an eccentric cam 11.
Therefore, the spacer 70 can reduce the surface pressure between the inner peripheral surface of the cam groove 69 and the outer peripheral surface of the eccentric cam 41, thereby improving the wear resistance.

FIGS. 16 to 19 show an embodiment according to the third aspect of the present invention, in which the structure of the frame 45 is further changed.
This is a modification of the shape and arrangement of the disk housing 34.

That is, the frame 45 is mounted on the cylinder head 4.
3 is formed so as to surround the entire upper end portion, that is, the entire intake side and the exhaust side, and is fixed to the upper end portion of the cylinder head 43 by a bolt 44. The support portions 45a, 45a extending in the front-rear direction of the engine are arranged along both side edges of the upper end portion of the cylinder head 43, and are provided between the front and rear end portions of the support portions 45a, 45a. Partition walls 45d, 45d are provided integrally with the partition wall. Also,
Four cross beams 45 installed between the two support portions 45a, 45a
are the intake-side sleeve 28 disposed at one end of the intake-side camshaft 22 on both sides of the lower surface;
The arc-shaped grooves 67 and 73 are formed such that the upper half thereof and the exhaust-side sleeve 80 arranged at one end of the exhaust-side camshaft 72 for opening the opening are loosely fitted with a certain gap. An arc-shaped bearing groove 46 for receiving the control shaft 42 is formed in the shaft. A shaft hole 45c for press-fitting and fixing the base of the short support shaft 40 is formed substantially at the center of the cross beam portion 45b. Also, the frame 45
A rocker cover 49 is directly fixed to an upper end portion of the cover with bolts.

In the disk housing 34, unlike the above embodiments, one end supported by the support shaft 40 of the boss 35 is disposed at the center side, and a second cam hole 74 is formed in this one end. Is formed, and a cam hole 39 in which the above-described eccentric cam 41 is rotatably provided is formed at the other end. In the second cam hole 74, a support shaft 4 is provided.
The second eccentric cam 75 rotatably supported at the leading end of the second eccentric cam 75
Are provided rotatably.

Further, the second eccentric cam 75 is provided as shown in FIG.
C ring 7 fitted to the tip of the support shaft 40 as shown in FIG.
6. Furthermore, the frame 4
The hydraulic actuator 52 of the drive mechanism 51 is fixed to the partition wall 45d on one end side of the bolt 5 by bolts.

The intake and exhaust camshafts 2
The brackets 2 and 72 are supported by cam grooves (not shown) at the upper end of the cylinder head 43 and brackets 66 and 77.
The control shaft 42 is supported by the bearing groove 46 and the bearing cap 47 in the same manner as described above.

Therefore, according to this embodiment, when the control shaft 42 rotates in one direction via the hydraulic actuator 52 in accordance with a change in the engine operating state, the eccentric cam 41 rotates eccentrically, and accordingly, the second eccentric cam 41 rotates. Eccentric cam 75 also supports the spindle 4
It rotates eccentrically in the same direction about 0. Therefore, the disk housing 34 swings around the support shaft 40 as a fulcrum. As a result, the center Y of the annular disk 29 is eccentric or concentric with the center X of the drive shaft 21, and the above-described operation is obtained.

In this embodiment, in particular, the frame 45 is
Rather than being provided individually on the intake side and the exhaust side as in the other embodiments, they are integrally provided so as to surround them, so that the number of parts is reduced as compared with the case where they are individually provided, and the structure is reduced. Simplified. Therefore, it is possible to improve the manufacturing operation efficiency and the assembling operation efficiency, reduce the cost, and reduce the weight. Further, since the support portions 45a, 45a are located on both sides of the cylinder head 43, there is no obstruction wall at the center, and the cylinder head 43 is in an open state. The property becomes good.

Further, since the upper end of the frame 45 is formed in the same shape as the rocker cover 49, and the rocker cover 49 is directly attached, the frame 45 and the rocker cover 4 are formed.
9 can be integrated.

Further, since the support shaft 40 is provided at the center position of the cross beam portion 45b and one end of the disk housing 34 is arranged at the center side of the cylinder head 43, the whole apparatus can be made compact in the width direction of the cylinder head 43.

Further, the hydraulic actuator 52 is connected to the frame 4
Since such directly attached to 5 of the partition wall 45d, oil
The mounting workability of the pressure actuator 52 is also improved.
Further, the cross beam portion may be extended from the support portion 45a of the frame body 45, and the upper surface of the camshaft 22 may be supported.

[0057]

As is apparent from the above description, according to the present invention, since the components of the control shaft , the camshaft, and the control mechanism are supported by the frame, the entire components are Can be unitized, and the workability of assembling the cylinder head is improved.

According to the second aspect of the present invention,
Install the actuator directly on the partition of the frame.
Therefore, the workability of mounting the actuator is also improved.
You.

Further, by unitizing the above components,
The accuracy of centering and clearance of each component can be improved, and the definitive positioning of the control shaft with respect to the frame makes it easier to obtain the positional accuracy between the center of the drive shaft and the center of the disk. The accuracy of assembly can be improved.

Further, according to the third aspect of the present invention, the number of parts can be reduced and the structure can be simplified as compared with the case where the frame bodies are individually provided on the intake side and the exhaust side. As a result, the efficiency of the manufacturing operation can be improved, the cost can be reduced, and the weight can be reduced. Further, since the vicinity of the center of the upper end of the cylinder head is open, the attachment of an ignition plug and the like is also improved.

[Brief description of the drawings]

FIG. 1 is a sectional view taken along line AA of FIG. 2 showing a first embodiment of the present invention .

FIG. 2 is a sectional view taken along line BB of FIG. 1;

FIG. 3 is a plan view of the embodiment.

FIG. 4 is a sectional view taken along line CC of FIG. 3;

FIG. 5 is a sectional view taken along line DD of FIG. 3;

FIG. 6 is a sectional view taken along line EE of FIG. 3;

FIG. 7 is a schematic diagram showing a driving mechanism of the present embodiment.

FIG. 8 is a sectional view taken along the line BB of FIG. 1 showing the operation of the present embodiment.

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

FIG. 10 is a sectional view taken along line FF of FIG. 11 showing a second embodiment of the present invention.

FIG. 11 is a sectional view taken along line GG of FIG. 10;

FIG. 12 is a plan view of the present embodiment.

FIG. 13 is a sectional view taken along line HH of FIG. 12;

FIG. 14 is a sectional view of a main part showing a third embodiment of the present invention.

FIG. 15 is a sectional view showing a main part of a fourth embodiment of the present invention.

FIG. 16 is a transverse sectional view of the embodiment according to the third invention.

FIG. 17 is a plan view showing the embodiment.

FIG. 18 is a sectional view taken along line JJ of FIG. 17;

FIG. 19 is a cross-sectional view showing a frame provided in the present embodiment.

FIG. 20 is a sectional view of a conventional intake and exhaust valve drive control device.

FIG. 21 is a sectional view taken along line II of FIG. 16;

[Explanation of symbols]

 Reference numeral 21: drive shaft 22, 70: cam shaft 27: flange 32: flange 29: annular disk 29b, 29c: pin hole 30, 33: engagement groove 34: disk housing 36, 37: pin 40: support shaft 41: Eccentric cam 42 ... Control shaft 45 ... Frame body 45a ... Support part 45b ... Transverse beam part 46 ... Bearing groove 51 ... Drive mechanism

──────────────────────────────────────────────────続 き Continuation of the front page (72) Inventor Akira Hidaka 1370 Onna, Atsugi-shi, Kanagawa Inside Unisia Gex Co., Ltd. (56) References JP-A-57-173655 (JP, A) Jpn. (JP, U) JP-A 4-82342 (JP, U) JP 2-19522 (JP, Y2) (58) Fields investigated (Int. Cl. ⁷ , DB name) F01L 13/00 301 F02F 1 /twenty four

Claims (3)

(57) [Claims] 1. A drive shaft provided at a position above a cylinder head along the front-rear direction of an engine, and a cam rotatably provided coaxially with the drive shaft and operating an intake valve or an exhaust valve on the outer periphery. A control mechanism for connecting the drive shaft to the camshaft and displacing with respect to the axis of the drive shaft to change the angular velocity between the drive shaft and the camshaft; and An intake / exhaust valve drive control device having a drive mechanism for controlling displacement of the mechanism via a control shaft, comprising: a pair of support portions formed at an upper end portion of the cylinder head along a longitudinal direction of the engine; A frame body including a cross beam portion connected from a right angle direction is provided therebetween, and the control system is provided between a bearing groove formed on an upper surface of the cross beam portion and a bearing cap mounted on an upper portion of the cross beam portion. As well as rotatably supported a shift, shape the lower surface of the horizontal beam portion
The camshaft is supported in the formed cam bearing groove.
And the whole of each component is unitized, and the unit
At the upper end of the cylinder head
An intake / exhaust valve drive control device for an internal combustion engine, characterized by being supported by a formed cam bearing . 2. An intake / exhaust valve drive control apparatus for an internal combustion engine according to claim 1, wherein an actuator of said drive mechanism for controlling rotation of said control shaft is fixed to said frame. 3. The intake and exhaust system of an internal combustion engine according to claim 2, wherein both support portions of the frame body are arranged on both sides of the engine, and a cross beam portion is laid across the intake side and the exhaust side. Valve drive control device.