JPH06185321A - Suction and exhaust valve drive control device of internal combustion engine - Google Patents

Abstract

PURPOSE:To prevent lowering of controlling precision of valve timing due to hammering sound and abrasion following rotating torque fluctuation of a camshaft while variably controlling the valve timing of suction and exhaust valves. CONSTITUTION:This suction and exhaust valve drive control device of an internal combustion engine is arranged between a camshaft 22 coaxially arranged on a drive shaft 21 synchronously rotating with an engine and a flange part 32 of a sleeve 28 connected to and fixed on a flange part 27 of the camshaft 22 and the drive shaft 21. Additionally it is furnished with a circular disc 29 free to oscillate around a shaft center X of the drive shaft 21 as its center through a disc housing 34, a pair of pins 36, 37 projectively provided on the circular disc 29 and engaged in each of engagement grooves 30, 33 and a drive mechanism to oscillate the disc housing 34 by an eccentric cam 41 in accordance with an engine driving state.

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 type have been provided, and one of them is, for example, Shoukai 57-198.
Those described in Japanese Patent No. 306, etc. are known.

The outline will be described with reference to FIGS. 20 and 21. In the figure, numeral 2 is rotatably provided on the outer periphery of the camshaft 1 to open the intake valve 16 against the spring force of the valve spring 17. The cam 2 is a cam that is axially positioned by a cam bearing bracket 3 and a flange portion 5 fixed to the cam shaft 1 via a key 4. Further, a U-shaped groove 6 is formed on the flange portion 7 formed on one side of the cam 2, and a U-shaped groove 8 is also formed on the flange portion 5. An annular disc 9 is interposed between the flange portions 5 and 7.
This disk 9 has both U-shaped grooves 6 at opposite positions on both sides.
Pins 10 and 11 for locking to 8 are provided,
The outer periphery 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 protrusion 12a on the outer periphery, and a gear portion 12b provided on the opposite side of the protrusion 12a pivotally supports a rocker arm 15. It meshes with a gear ring 14a on the outer circumference of the rocker shaft 14.

The control ring 12 is oscillated in one direction or the other direction according to the engine operating state 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 disc 9 is at the position shown in FIG. 20, the rotation centers of the camshaft 1 and the disc 9 coincide with each other, so that the disc 9 is inserted through the pin 11 and the U-shaped groove 8 into the camshaft 1. While rotating in synchronization with
The cam 2 rotates synchronously with the cam shaft 1 via the pin 10 and the U-shaped groove 6.

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

[0006]

However, in the above-mentioned conventional apparatus, the control ring 12 is provided with the gear portion 12b and the gear ring 1.
Since it is rocked by meshing rotation with 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 repeated load in the forward and reverse rotation directions, A tapping sound is generated between the gear portion 12b and the gear ring 14a, and the both 12b,
Abrasion occurs between 14a over time, and the swinging action of the control ring 12 becomes unstable. As a result, the variable control accuracy of the valve timing is reduced.

In order to assemble such a device, the assembly unit of the cam shaft 1 to which the cam 2, the disc 9, the control ring 12 and the like are assembled, and the rocker shaft 14 also serving as the control shaft are attached to the cylinder head 18. It is designed to be assembled separately. For this reason, when assembling to the cylinder head 18, it is necessary to assemble while engaging the gear portion 12b of the control ring 12 with the gear ring 14a of the rocker shaft 14 at an optimum position. As a result, the assembling work becomes complicated and the work efficiency is lowered.

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

[0009]

The present invention has been devised in view of the above problems of the prior art. The invention of claim 1 is provided above the cylinder head in the longitudinal direction of the engine. A drive shaft, a cam shaft provided coaxially with the drive shaft so as to be rotatable relative to each other, and a cam shaft having a cam for operating an intake valve or an exhaust valve on an outer periphery, and a cam shaft swingable with respect to the axis of the drive shaft. A disk housing, and a disk that is rotatably supported on the inner circumference of the disk housing and links the drive shaft and the cam shaft. The disk moves from the axis of the drive shaft as the disk housing swings. In an intake / exhaust valve drive control device that eccentrically moves to variably control the operating angle of the intake / exhaust valve, one end side of the disk housing is rotatably supported by a support shaft, and the other end is driven by a cam hole. Is characterized in that slidably disposed an eccentric cam rotated by the mechanism.

According to a second aspect of the present invention, a pair of support portions formed along the longitudinal direction of the engine are provided at the upper end portion of the cylinder head, and a lateral beam portion connected between the support portions at a right angle. A frame body is provided, a bearing groove for bearing a control shaft of the drive mechanism is formed in an upper end portion of the horizontal beam portion, and a shaft hole for holding the support shaft is formed at a predetermined position of the horizontal beam portion. I am trying.

According to a third aspect of the present invention, both supporting portions of the frame body are arranged on both sides of the engine, and a lateral beam portion is provided so as to extend between the intake side and the exhaust side.

[0012]

According to the present invention having the above-described structure, when the center of the annular disc is coincident with the center of the drive shaft, the camshaft is rotated through the annular disc or the like in synchronization with the drive shaft without phase difference. To do.

On the other hand, when the drive mechanism causes the disk housing to swing in one direction as the engine operating condition changes, the center of the annular disk is eccentric with the center of the drive shaft. Therefore, the sliding positions of the engagement groove of the flange portion on the drive shaft side and the pin on one side, and the engagement groove of the flange portion on the cam shaft 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 engagement groove on the drive shaft side and the pin approaches the center of the drive shaft, the sliding position between the engagement groove on the cam shaft side and the pin reversely moves away from the drive shaft center. The angular velocity of the annular disc becomes small with respect to the drive shaft, and the angular velocity of the camshaft also becomes small with respect to the annular disc. Therefore,
The camshaft has a double decelerated shape with respect to the drive shaft, and a desired valve timing can be obtained via the cam by the deceleration action. When the annular disc is eccentric to the opposite position to the above, the camshaft is double speeded up with respect to the drive shaft.

Further, the swing of the disc housing is
Since the eccentric cam is used instead of the gear or the like, even if an alternating load is generated in the disk housing due to the rotational fluctuation torque of the cam shaft, it is possible to prevent the occurrence of tapping noise and wear over time.

According to the second aspect of the invention, when assembling the apparatus, the disc, the disc housing and the cam shaft are assembled in advance at positions corresponding to the respective cylinders of the drive shaft,
This assembly unit is assembled to the frame body via a support shaft or the like that is previously fixed to the frame body. After that, if the control shaft is held in the bearing groove and the bearing cap is fixed from above, and the frame is fixed to the upper end of the cylinder head with bolts, the whole assembly can be easily assembled.

According to the third aspect of the present invention, the frame body is not provided individually on the intake side and the exhaust side of the cylinder head, but is provided so as to surround the intake side and the exhaust side.
The number of parts can be reduced, the assemblability can be improved, and the weight can be reduced as compared with the case where they are individually provided.

[0017]

1 to 3 show a first embodiment in which an intake / exhaust valve drive control device according to the invention of claims 1 and 2 is applied to a four-cylinder engine.
1 shows an embodiment, and 21 in FIG. 1 is a drive shaft to which a rotational force is transmitted from a crankshaft of an engine (not shown) through a sprocket,
Reference numeral 2 denotes a cam shaft which is arranged on the outer periphery of the drive shaft 21 with a constant gap and is provided coaxially with the center X of the drive shaft 21, and 45 is fixed to the upper end of the cylinder head 43 with 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 in an inner hollow shape in order to reduce the weight.

The cam shaft 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 as shown in FIG. A plurality of cams 26 that open the valve 23 against the spring force of the valve spring 24 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 provided with an elongated rectangular engaging groove 30 extending from the hollow portion in the radial direction, and the annular disc 2 is circumferentially formed on 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 generally rectangular frame shape which surrounds the intake side of the upper end of the cylinder head 43, and is arranged inside the rocker cover 49 to extend in the longitudinal direction of the engine. A pair of support portions 45 on both sides extending along
a, 45a, and a plurality of horizontal beam portions 45b, which are erected from the right angle direction between the support portions 45a, 45a. The horizontal beam portion 45b has a semicircular bearing groove 46 for bearing a control shaft 42, which will be described later, formed on one end side of the upper surface thereof, and the camshaft 22 at a substantially central position on the lower surface thereof.
A cam bearing groove 50, which is an arc groove for bearing the upper half, is formed. Further, a shaft hole 45c for rotatably supporting one end of a bearing 40 described later is formed at a substantially central position on the other end side of the horizontal beam portion 45b.

The sleeve 28 has a small diameter one end 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 toroidal plate shape, an inner diameter of which is substantially the same as the inner diameter of the cam shaft 22, and an annular gap S is formed between the annular disc 29 and the outer peripheral surface of the drive shaft 21. In addition, the outer peripheral portion 29a having a small width is rotatably supported by the inner peripheral surface 34a of the annular disc housing 34. In addition, a pair of pins 36 and 37 that engage with the engagement grooves 30 and 33 are provided in the pin holes 29b and 29c that are formed at the opposite positions on the diameter line. The pins 36 and 37 project in opposite directions to each other in the axial direction of the camshaft, the base portions are rotatably supported in the pin holes 29b and 29c, and the pins 36 and 37 are provided on both side edges of the tip portion as shown in FIGS. As shown in FIG.
Flat portions 36a, 36b, 37a, 37b having a width across flats are formed so as to come into contact with 0a, 30b, 33a, 33b.

As shown in FIG. 2, the disc housing 34 has a substantially annular shape, and a boss portion 35 provided at the upper end of the outer periphery is formed with a substantially U-shaped support groove 38 at the outer edge of one end. A cam hole 39 is formed through the other end of the boss portion 35. Then, one end of the disk housing 34 is rotatably and slidably supported by the support shaft 40 inserted into the support groove 38, and the eccentric cam 41 inserted into the cam hole 39 is rotated. The disc 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 the shaft hole 45c, and has both end edges of a portion corresponding to the disc housing 34. Flat contact surfaces 40a, 40b are formed on the outer surface of the support groove 38. The contact surfaces 40a, 40b are in contact with the facing surfaces 38a, 38b of the support groove 38 in a surface contact state.

The eccentric cam 41 has a ring shape, the outer diameter thereof is set to be slightly smaller than the inner diameter of the cam hole 39, and the wall thickness in the circumferential direction is gradually increased from the thin portion 41a to the thick portion 41a.
It has changed to b. Further, it is fixedly supported by the hollow control shaft 42 through a through hole 41c formed so as to penetrate therethrough in the axial direction. As shown in FIGS. 1 and 3, the control shaft 42 extends along the front-rear direction of the engine, and has a bolt 4 on the bearing groove 46 of the lateral beam portion 45b and an upper portion of the frame body 45.
The bearing cap 47 is fixed between the bearing cap 47 and the bearing cap 47. Further, the control shaft 42 is configured to be rotationally controlled by the drive mechanism 51.

It can be said that 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. The hydraulic actuator 52 is rotatable in the tubular housing 54 while separating the first oil chambers 56, 56 and the second oil chambers 57, 57 in which the rotary vanes 55 of two blades are diagonally located. A rotary vane 55 is provided and is connected to the control shaft 42. The hydraulic circuit 53 includes the first and second oil chambers 5
A pair of first and second oil passages 58 for supplying and discharging hydraulic pressure to and from
a, 58b, a 4-port 2-position electromagnetic switching valve 59 provided at the ends of the oil passages 58a, 58b, and an oil pump 6 provided at the upstream end of the oil main gallery 60.
1, a drain passage 63 that appropriately communicates with the oil passages 58a and 58b to return the working oil into the oil pan 62, and a relief valve 64 that controls the pump discharge pressure to a constant pressure. Further, the electromagnetic switching valve 59 is switched by an ON-OFF signal from the controller 65 that 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 pump 61 to operate. While communicating with the first oil passage 58a, the second oil passage 58a
b and the drain passage 63 are communicated with each other, and in response to an ON signal, they are communicated with each other in the opposite manner.

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 65 to the electromagnetic switching valve 59, and the oil pump 61
The hydraulic oil discharged from the first oil chambers 56, 56 flows into the first oil chambers 56, 56, while the hydraulic oil in the second oil chambers 57, 57 is discharged from the drain passage 63.
Is discharged into the oil pan 62. For this reason, the rotary vane 55 rotates counterclockwise in the drawing to rotate the control shaft 42.
To rotate in the circumferential direction. Therefore, the eccentric cam 41 is
As shown in FIG. 8, it rotates counterclockwise in the drawing from the position shown in FIG. 2 (broken line position) to the θ angle position, and the maximum thick portion 41b moves to the upper side. Therefore, the disc housing 34 is supported by the support shaft 40 through the cam hole 39.
The center Y of the annular disk 29 is eccentric with the center X of the drive shaft 21 (camshaft 22). That is, as the eccentric cam 41 rotates, the cam hole 39 of the boss portion 35
When the side is pulled to the upper left, the facing surface 3 of the support groove 38
While 8a and 38b slide on the contact surfaces 40a and 40b of the support shaft 40, the whole swings counterclockwise and is eccentric by a predetermined amount. Therefore, the engagement groove 33 on the sleeve 28 side and the pin 3
7 and the sliding position between the locking groove 30 on the camshaft 21 side and the pin 36 moves for each rotation of the drive shaft 21, and the angular velocity of the annular disk 29 changes to cause unequal angular velocity rotation.

That is, when the sliding position of the locking groove 30 and the pin 36 approaches the center X of the drive shaft 21, the sliding position of the locking groove 33 and the pin 37 moves away from the center 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 region, the controller 65 outputs an OFF signal to the electromagnetic switching valve 59, and the working oil in the first oil chambers 56, 56 is discharged from the drain passage 63. At the same time, the oil pressure is sent from the oil pump 61 into the second oil chambers 57, 57, and the rotating vanes 5
5 reversely rotates in the clockwise direction. 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 moved to the drive shaft 21.
Coincides with the center X of. Therefore, in this case, a rotational phase does not occur 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 aligned, so that the space between the two 22 and 29 is the same. No rotational phase difference occurs. Therefore, as the drive shaft 21 rotates, the connecting shaft 31
The sleeve 28 rotates synchronously via the pin, the sleeve-side locking groove 33, the pin 37, the annular disc 29, and the pin 3
6. The camshaft 22 also rotates synchronously via the locking groove 30 on the camshaft 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 and the valve timing changes as shown in FIG. The valve lift changes according to the phase difference of the cam shaft 22 with the valve lift kept constant.

That is, when the angular velocity of the camshaft 22 is relatively large, the rotation phase with respect to the drive shaft 21 advances until both the speeds 21 and 22 become constant, and eventually when the angular velocity of the camshaft 22 relatively decreases. Phase is both 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, as described above, in the engine low speed and low load region, 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 becomes earlier. This reduces the valve overlap of the intake and exhaust valves, reduces the residual gas in the combustion chamber,
Fuel efficiency can be improved by stable combustion. 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 range, the operating angle becomes large as shown by the solid line in FIG. 9B, the same timing is advanced and the closing timing is delayed, so that the intake charge 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 41 is further rotated clockwise to move the disc housing 34 and the annular disc 29 in the lower right direction, as shown by the one-dot chain 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 engine operation, and in particular, the disk housing 34 is eccentric without using a gear or the like as in the conventional case. Since the cam 41 is used for swinging, it is possible to reliably prevent generation of hammering noise, abrasion, etc. due to the alternating load of the disk housing 34 due to the fluctuation of the rotational torque of the cam shaft 22.

Further, as described above, since the pins 36, 37 are formed with the flat surface portions 36a, 36b, 37a, 37b on both side edges, the facing inner surfaces 30a, 30a of the locking grooves 30, 33,
It comes into contact with 30b, 33a and 33b in a surface contact state. Therefore, the flat surface portion 36 during rotation transmission from the drive shaft 21 to the camshaft 22 and in the eccentric state of the annular disk 29.
a, 36b, 37a, 37b and facing inner surfaces 30a, 30
When sliding with b, 33a and 33b, a concentrated load between them is prevented from being generated, and the surface pressure is reduced. As a result, the locking groove 3
0, 33 and the pins 36, 37 are prevented from being worn over time, and the tapping noise between the flange portions 27, 32 and the pins 36, 37 due to the fluctuation of the rotational torque of the camshaft 22 and the valve are prevented. It is possible to prevent a decrease in control accuracy due to a timing shift.

Furthermore, since the pins 36 and 37 are rotatably supported in the pin holes 29b and 29c of the annular disc 29, the pins 3 and 37 can be rotated even when the annular disc 29 swings.
6 and 37 are rotated appropriately so that the flat portions 36a, 36b and 37
a, 37b and inner facing surfaces 30a, 30 of the locking grooves 30, 33
b, 33a and 33b are always in surface contact with each other. Therefore, the occurrence of wear between the both 30, 36, 33, 37 is more reliably prevented.

Moreover, the contact surfaces 40a, 40b of the support shaft 40
Is also formed in a flat shape and comes into contact with the facing surfaces 38a and 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. In addition, the contact surface 40a, 4
Since 0b is always in surface contact with the facing surfaces 38a, 38b, the occurrence of wear or the like is further prevented.

Further, the disk housing 34 does not simply swing around the fulcrum, but the support groove 3 is supported on the support shaft 40.
Since it oscillates while slidingly moving through 8, it is possible to increase the amount of eccentricity of the center Y of the annular disk 29 with respect to the center X of the drive shaft 21, that is, the offset amount.

Further, since the frame 45 has a structure in which the control shaft 42, the support shaft 40, and the like are supported, the entire unit including the drive mechanism 51 can be unitized, and the cylinder head 43 can be assembled. Is extremely good.

That is, in order to assemble the respective components to the cylinder head 43, first, the sleeves 28 are respectively press-fitted to the positions corresponding to the respective cylinders of the drive shaft 21 and are connected by the connecting shafts 31, and then the pins 36, 37 is inserted into the pin holes 29b and 29c of the annular disk 29. After that, the annular disc 29, the disc housing 34, and the cam shaft 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 portion of the drive shaft 21 to prevent the cam shafts 22 from coming off.

This assembly unit is assembled to the frame body 45, and the assembly unit of the frame body 45 is fixed to the upper end of the cylinder head 43 by the bolts 44 while supporting the cam shaft 22 with the cam bearing groove 50. The support shaft 40 is inserted through the shaft holes 45c of the frame body 45 in advance, and is fitted into the support groove 38 of the disc housing 34 when the assembly unit such as the drive shaft 21 is assembled to the frame body 45.

Further, since the horizontal beam portion 45b also serves as the cam bearing bracket of the camshaft 22 and the bearing of the control shaft 42, the number of parts can be reduced, the assembling property is further improved, and the center of the drive shaft 21 is improved. X and control shaft 4
The positional 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 the frame 45 is modified.
The horizontal beam portion 45b connected between 45a has only the bearing groove 46 of the control shaft 42 on the upper surface, and
It was formed separately from the bearing brackets 66 ... Also,
A large-diameter circular arc groove 67 for ensuring loose insertion of the camshaft 22 is formed on the lower surface of the lateral beam portion 45b, as shown in FIG.

Therefore, the control shaft 42 is attached to the frame 45.
A unit assembled with components such as the eccentric cam 41 and
It becomes possible to assemble the cylinder head 43 bearing the camshaft 22 with the bracket 66 in advance afterwards.
Therefore, when the unit of the frame body 45 and the engine body are manufactured separately, the assembling property becomes good.

FIG. 14 shows a third embodiment of the present invention. A support hole 68 is formed at one end of the boss portion 35 of the disk housing 34 in place of the support groove, and a circle inserted into the support hole 68. While the columnar support shaft 40 is used as the swing support point, the boss portion 3
At the other end of 5, a cam groove 69 having a substantially U-shape is used 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 hole 68 is
Since it is easy to center the center of the disc and the center X of the drive shaft 21, the relative positioning of the disc 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 wear-resistant material is interposed between the U-shaped cam groove 69 and the 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 to improve the wear resistance.

16 to 19 show an embodiment according to the invention of claim 3, in which the structure of the frame 45 is further modified, and
The shape and arrangement of the disc housing 34 are changed.

That is, the frame body 45 is the cylinder head 4
3 is formed so as to surround the entire upper end portion, that is, the entire intake side and 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 along the front-rear direction of the engine are arranged along both side edges of the upper end portion of the cylinder head 43, and between the front-rear end portions of the support portions 45a, 45a. The partition portions 45d, 45d are integrally provided on the. Also,
Four lateral beam parts 45 provided between both support parts 45a, 45a
b ... Intake-side sleeves 28 arranged on one end side of the intake-side camshaft 22 on both sides of the lower surface, and an exhaust valve 71.
The exhaust side sleeve 80 disposed on one end side of the exhaust side cam shaft 72 for opening the opening is formed with circular arc grooves 67 and 73 in which the upper half is loosely fitted with a constant gap, while one side portion of the upper surface is formed. An arc-shaped bearing groove 46 for bearing the control shaft 42 is formed therein. Further, a shaft hole 45c for press-fitting and fixing the base portion of the short support shaft 40 is formed at substantially the center of the horizontal beam portion 45b. In addition, the frame body 45
A rocker cover 49 is directly fixed to the upper end of the with a bolt.

Unlike the above-mentioned embodiments, the disc housing 34 has one end portion, which is supported by the support shaft 40 of the boss portion 35, disposed at the center side position, and the second cam hole 74 is provided at this one end portion. And a cam hole 39 in which the above-mentioned eccentric cam 41 is rotatably provided is formed at the other end. The support shaft 4 is provided in the second cam hole 74.
Second eccentric cam 75 rotatably supported at the end of 0
Is rotatably provided.

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

Incidentally, the intake side and exhaust side camshafts 2
2, 72 are supported by a cam groove (not shown) at the upper end of the cylinder head 43 and brackets 66, 77.
Further, the control shaft 42 is borne by the bearing groove 46 and the bearing cap 47 as described above.

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

Further, in this embodiment, especially the frame body 45 is
Instead of providing them individually on the intake side and the exhaust side as in the other embodiments, they are integrally provided so as to surround both, so the number of parts is reduced and the structure is reduced compared to the case where they are provided individually. To be simplified. Therefore, the manufacturing work efficiency and the assembling work efficiency can be improved, the cost can be reduced, and the weight can be reduced. Further, since the support portions 45a, 45a are located on both sides of the cylinder head 43, there is no obstacle wall at the center and the cylinder head 43 is in an open state. Good quality.

Moreover, since the upper end of the frame body 45 is formed in the same shape as the rocker cover 49 and the rocker cover 49 is directly attached, the frame body 45 and the rocker cover 4 are attached.
It becomes possible to integrate with 9.

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

Further, the hydraulic actuator 52 is attached to the partition wall 4
Since it is attached directly to the 5d, the attaching workability is also improved. Further, a lateral beam portion may be extended from the support portion 45a of the frame body 45 so that the upper surface of the cam shaft 22 can be supported.

[0057]

As is apparent from the above description, according to the present invention, the eccentric swing of the disk housing with respect to the drive shaft is performed by using an eccentric cam, not by a gear or the like as in the conventional case. As a result, it is possible to obtain highly accurate variable control of the valve timing by smooth eccentric movement of the annular disc with respect to the center of the drive shaft, and it is possible to reliably generate tapping noise and wear between the eccentric cam and the disc housing. To be prevented. As a result, durability is improved, and highly accurate variable control of valve timing can be maintained for a long period of time.

Further, according to the inventions of claims 2 and 3, since the structure supports the components such as the control shaft, the support shaft and the disk housing by the frame, the components can be unitized. Moreover, since the work of meshing the gears with each other unlike the conventional case is eliminated, the assemblability to the cylinder head is improved.

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

Furthermore, according to the third aspect of the invention, the number of parts can be reduced and the structure can be simplified as compared with the case where the frame body is individually provided on the intake side and the exhaust side. As a result, the manufacturing work efficiency 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 opened, the attachability of the spark plug or the like is improved.

[Brief description of drawings]

1 is a sectional view taken along the line AA of FIG. 2 showing a first embodiment of the inventions of claims 1 and 2. FIG.

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

FIG. 3 is a plan view of the present embodiment.

4 is a cross-sectional view taken along the line CC of FIG.

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

6 is a cross-sectional view taken along the line EE of FIG.

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

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

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 taken along line FF of FIG. 11 showing a second embodiment of the present invention.

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

FIG. 12 is a plan view of this embodiment.

13 is a cross-sectional view taken along line HH of FIG.

FIG. 14 is a cross-sectional view of the essential parts showing the third embodiment of the present invention.

FIG. 15 is a cross-sectional view of essential parts showing a fourth embodiment of the present invention.

FIG. 16 is a transverse sectional view of an embodiment according to the invention of claim 3;

FIG. 17 is a plan view showing the same embodiment.

18 is a cross-sectional view taken along the line JJ of FIG.

FIG. 19 is a cross-sectional view showing a frame body used in this example.

FIG. 20 is a cross-sectional view of a conventional intake / exhaust valve drive control device.

21 is a cross-sectional view taken along the line I-I of FIG.

[Explanation of symbols]

 21 ... Drive shaft 22, 70 ... Cam shaft 27 ... Flange part 32 ... Flange part 29 ... Annular disk 29b, 29c ... Pin hole 30, 33 ... Engagement groove 34 ... Disk housing 36, 37 ... Pin 40 ... Spindle 41 ... Eccentric cam 42 ... Control shaft 45 ... Frame 45a ... Support 45b ... Cross beam 46 ... Bearing groove 51 ... Drive mechanism

 ─────────────────────────────────────────────────── ─── Continuation of the front page (72) Inventor Akira Hidaka 1370 Onna, Atsugi, Kanagawa

Claims (3)

[Claims] 1. A drive shaft which is provided above the cylinder head along the longitudinal direction of the engine, and a cam which is provided on the outer periphery of the drive shaft so as to be rotatable relative to each other and which operates an intake valve or an exhaust valve. A camshaft having the same; a disc housing swingably provided with respect to the axis of the drive shaft; and a disc rotatably supported on the inner circumference of the disc housing to link the drive shaft and the camshaft. An intake / exhaust valve drive control device that variably controls the operating angle of the intake / exhaust valve by eccentrically moving the disk from the axial center of the drive shaft as the disk housing swings. The eccentric cam which is rotated by a drive mechanism is slidably provided in the cam hole of the other end while supporting the rotatably supported shaft of the internal combustion engine. Control device. 2. A frame body is provided at an upper end portion of the cylinder head, the frame body having a pair of support portions formed along a longitudinal direction of the engine and a lateral beam portion connected between the support portions at a right angle. 2. A bearing groove for bearing a control shaft of the drive mechanism is formed in an upper end portion of the horizontal beam portion, and a shaft hole for holding the support shaft is formed at a predetermined position of the horizontal beam portion. An intake / exhaust valve drive control device for an internal combustion engine as described above. 3. The intake / exhaust valve for 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 lateral beam portion is provided over the intake side and the exhaust side. Drive controller.