JPH11132021A - Variable valve system for internal combustion engine - Google Patents

Abstract

PROBLEM TO BE SOLVED: To permit variable operation of cam lift only when a cam is on a base circle, by a simple structure. SOLUTION: A variable mechanism in which supporting points A, B of oscillation of a rocker arm 4 are made variable, is made up of plural supports 6, 7 which are mounted to a cylinder head so that they can support the oscillation of the rocker arm 4, and one or more of which can be moved to the cylinder head. Further, a timing control mechanism (a timing control shaft 90, a flange part 87c) which permits the movement of the support 7 only when the rocker arm 4 is slidably in contact with a base circle of a cam 1a, is provided.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a variable valve apparatus for varying the lift of intake and exhaust valves that are opened and closed in synchronization with a crankshaft of an internal combustion engine.

[0002]

2. Description of the Related Art Conventionally, as this kind of variable valve train,
Japanese Patent Application Laid-Open No. 6-280523 is known. This device includes a cam that is rotated in synchronization with a crankshaft of an internal combustion engine, a rocker arm that is swung by the rotation of the cam to lift a valve, and a variable mechanism that makes a rocking fulcrum of the rocker arm variable. And the lift amount of the valve can be adjusted.

In this conventional device, the variable mechanism defines a virtual swing fulcrum of the rocker arm and is composed of a large number of support links for supporting the rocker arm.
The lift amount of the valve is adjusted by making the rocking fulcrum of the rocker arm variable by the movement of the large number of support links.

[0004]

However, according to the above-mentioned conventional apparatus, a large number of supporting links are required to make the rocking arm of the rocker arm variable, so that the structure is complicated and the number of parts is large. It is disadvantageous in terms of cost and space. In addition, since the rocking fulcrum of the rocker arm is virtually defined by a large number of support links, there is a possibility that the play existing at the connecting portion of each link may move the rocking fulcrum of the rocker arm, and as a result, the valve The lift amount was not stable, and there was a risk of subtle changes.

In order to solve these problems, the applicant of the present invention has made intensive efforts, and in Japanese Patent Application No. 8-295421, a novel variable valve apparatus for changing the rocking fulcrum of the rocker arm with a simpler structure. Suggested. In this variable valve operating device, the variable mechanism is attached to the cylinder head at one end so as to be able to support the rocking of the rocker arm, and one or more of the variable mechanisms are constituted by a plurality of columns that are movable to the cylinder head. I have. The support column cannot move with respect to the cylinder head by holding the hydraulic pressure applied to the other end side, and can support the rocker arm swinging, and can move with respect to the cylinder head by releasing the hydraulic pressure As a result, the rocker arm cannot be swung. Thereby, the rocking fulcrum of the rocker arm can be changed with a simple structure by holding or releasing the hydraulic pressure acting on the other end of each pillar, and appropriately selecting the pillar that supports the rocker arm swing. .

However, in the above-mentioned variable valve operating device, the holding and release of the hydraulic pressure acting on the column of the variable mechanism is performed arbitrarily even during the valve lift. If the valve becomes a rocking fulcrum of the rocker arm and the valve is in a low lift state and lifted, and the other end of another pillar that was movable up to that time is held immobile due to hydraulic pressure, the rocker arm will be moved from that point on. The swing fulcrum is switched to another support, and the valve lift (high lift) is continued. Therefore, not only the lift amount is not stable,
The overall dimensions of the valve train may be inconsistent and the cam may return to the base circle and the valve may be seated and the tapping sound may be generated or damaged. For example, as described in Japanese Patent Application Laid-Open No. 7-49012, one solenoid valve per valve controls the holding and release of the hydraulic pressure acting on the other end of the column, and
It is possible to solve this problem by controlling the solenoid valve not to operate during the lift and prohibiting the variable lift operation. However, this variable valve apparatus is applied to a valve apparatus for a one-cylinder four-valve internal combustion engine. In this case, since one solenoid valve is required for each valve, the number of parts increases, the cost increases, and the control becomes complicated.

SUMMARY OF THE INVENTION It is an object of the present invention to provide a variable valve apparatus in which a variable operation of a lift amount is permitted only on a base circle of a cam with a simple configuration.

[0008]

According to the present invention, there is provided a cam which is rotatably disposed on a cylinder head of an internal combustion engine and is rotated in synchronization with a crankshaft. A rocker arm that is swung by sliding contact between a shaft and a cam integrally provided on the camshaft according to rotation of the camshaft to lift and open and close an intake / exhaust valve, and swing of the rocker arm A variable mechanism for varying the fulcrum, the variable valve operating device of the internal combustion engine in which the lift amount of the intake and exhaust valve is variable,
The variable mechanism is attached to the cylinder head so as to be able to support the rocker arm swinging, and one or more of the columns are configured to be movable to the cylinder head. There is provided a timing control mechanism that allows only while the rocker arm is in sliding contact with the base circle of the cam.

In the above means, the variable mechanism is
The rocker arm can support the rocker arm on an end side opposite to the intake / exhaust valve side end, and
A fixed support that is immovably attached to the cylinder head; and a fixed support that is movably attached to the cylinder head and that is immovable with respect to the cylinder head by holding a hydraulic pressure that acts on one end thereof. The support composed of one or more movable supports capable of supporting the rocker arm on the intake / exhaust valve side of the support part by the support, and releasing the hydraulic pressure acting on one end of the movable support to release the movable support A release mechanism that makes the cylinder head movable relative to the cylinder head, and the timing control mechanism allows release and return operations of the release mechanism only while the rocker arm is in sliding contact with the base circle of the cam. You may do it.

Further, in the above-mentioned means, the movable column is formed at one end of the movable column in the hole by being slidably fitted into a slide hole formed in the cylinder head. The release mechanism further comprising a pressure chamber, and a one-way valve interposed between the pressure chamber and an oil passage formed in the cylinder head, and allowing only oil flow from the oil passage to the pressure chamber. The one-way valve is movably moved to an open position where the one-way valve is pushed and opened at one end thereof, and a return position where one end thereof is separated from the one-way valve and maintains the one-way valve closed. A plunger attached to the cylinder head, wherein the timing control mechanism is movably fitted into a control hole formed in the cylinder head,
One end of the rocker arm is urged by a spring so as to be always in contact with the rocker arm, and moves in the control hole against the spring only at the time of rocking of the rocker arm by the cam. A control shaft that engages the plunger to prevent the movement of the plunger may be provided.

According to the above-mentioned means, the movement of the column of the variable mechanism is permitted only while the rocker arm is in sliding contact with the base circle of the cam by the timing control mechanism. It is prohibited and a stable lift can be obtained.

[0012]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS An embodiment in which a variable valve apparatus for an internal combustion engine according to the present invention is applied to an intake valve 3 will be described below with reference to the drawings.

In FIG. 1, a variable valve apparatus is rotatably disposed on a cylinder head 2 of an internal combustion engine, and is rotatable in synchronization with a crankshaft (not shown). The intake valve 3 that swings by sliding contact with a cam 1 a integrally provided on the camshaft 1 according to the rotation of the camshaft 1 to open and close the intake hole 21 formed in the cylinder head 2 against the valve spring 31. The rocker arm 4 includes a rocker arm 4 to be lifted, and a variable mechanism 5 that makes the rocking fulcrum A of the rocker arm 4 variable. The rocker arm 4 is disposed such that the end on the intake valve 3 side (one end in the longitudinal direction, which is the left end in the drawing) is located on the shaft portion 32 of the intake valve 3, and the shaft of the intake valve 3 is attached to this end. An adjustment screw 42 having a spherical protrusion 42a on one end side that is in contact with the tip 32a of the portion 32 is provided. In addition, a hemispherical concave portion 41 on which a fixed support 6 to be described later is supported, and a longitudinal end of the rocker arm 4 are provided at an end opposite to the end on the intake valve 3 side (the other end in the longitudinal direction which is the right end in the figure). A concave portion 43 is provided which extends perpendicularly to the direction and in which a movable column 7 described later is supported via a columnar pin 72. The recesses 41 and 43 are formed in series in the longitudinal direction of the rocker arm 4, and the recess 43 is located closer to the intake valve 3 than the recess 41.

The variable mechanism 5 is disposed between the rocker arm 4 and the cylinder head 2 and has a fixed support 6 forming a first swing support A and a movable support 7 forming a second swing support B. (Pin 72).

As shown in FIGS. 1 and 2, the fixed column 6 has a spherical joint 61 at one end, and a hole formed in the cylinder head 2 so as to extend toward the rocker arm 4. The other end of the cylinder head 2 is press-fitted from the surface of the cylinder head 2 facing the rocker arm 4 and fixed. The moving support 7 is provided with a large-diameter disk portion 71 at one end, and the other end side is inserted through a hydraulic lifter 8 into a hole 23 formed in the cylinder head 2 so as to extend toward the rocker arm 4. The rocker arm 4 is supported so as to be movable in a direction perpendicular to the longitudinal direction of the rocker arm 4 (vertical direction shown in FIG. 1). The fixed support 6 and the movable support 7 are arranged such that the movable support 7 is located closer to the intake valve 3 than the fixed support 6. The joint 61 of the fixed support 6 is moved in accordance with the movement of the movable support 7. Of the rocker arm 4 by the concave portion 41 can be released. The pin 7 is provided on the disk portion 71 of the moving support 7 in a direction perpendicular to the longitudinal direction of the rocker arm 4.
2, and a part of the outer peripheral surface of the pin 72 is rotatably supported by the concave portion 43 of the rocker arm 4.
As shown in FIGS. 2 and 3, both ends of the pin 72 are provided on a surface of the cylinder head 2 facing the rocker arm 4, and a pair of guides 2 projecting in parallel with the longitudinal direction of the rocker arm 4.
8 is fitted in a guide hole 28a. The guide hole 28a is formed in an arc shape centering on the first swing fulcrum A, and as described later, the movable support 7 moves and the rocker arm 4 moves the first swing fulcrum A (the fixed support 6). When swinging around the joint 61), the guide hole 28
When the pin 72 slides or rolls on the disk portion 71 along a, the rocker arm 4 swinging about the first swing fulcrum A is not hindered. Note that fixing rings 29 are fitted around the outer periphery of both ends of the pin 72 protruding from the guide hole 28a, thereby restricting the axial movement of the pin 72.

The hydraulic lifter 8, as shown in FIG.
A body 81 is press-fitted and fixed in the hole 23 and movably supports the movable column 7 in the inner hole. In the body 81, a pressure chamber 82 is formed between the inner hole and the other end of the movable support column 7, and a reservoir chamber 83 is formed between an annular groove formed on the outer periphery thereof and the hole 23. doing. The body 81 is formed with a passage 84 for communicating the pressure chamber 82 with the reservoir chamber 83, and a check ball 85 capable of opening and closing the passage 84 is provided in the passage 84. The pressure chamber 82 is filled with a sufficient amount of pressure oil to fill the pressure chamber 82, and this pressure oil moves between the reservoir chamber 83 and the pressure chamber 82 via the passage 84. The check ball 85 is urged by a spring 86 locked at one end to a retainer fixed to the body 81 so as to close the opening 84a of the passage 84 on the reservoir chamber 83 side by contact with the body 81. Thus, the communication between the reservoir chamber 83 and the pressure chamber 82 is always closed by the check ball 85, and is opened by moving the check ball 85 against the urging force of the spring 86. The pressure oil filled in the pressure chamber 82 is connected to the check ball 85 by the communication between the pressure chamber 82 and the reservoir chamber 83.
In the closed state, a pressure against the load applied from the rocker arm 4 to the movable support 7 is applied to the movable support 7. Between the disk portion 71 of the moving support 7 and the body 81,
A spring 9 is provided, and the movable column 7 is moved by the urging force of the spring 9 so that the disc 71
3 is always urged in the direction of pressing (upward direction in FIG. 1). In FIG. 6, reference numeral 88 denotes a discharge hole formed in the cylinder head 2 so as to always communicate with the reservoir chamber 83.

The cylinder head 2 is orthogonal to the hole 23,
A stepped hole 24 is formed so that one end on the small diameter portion side is open to the reservoir chamber 83. In the hole 24, a pin portion 8 which can move a check ball 85 against a spring 86 through a small diameter portion and a reservoir chamber 83 at one end thereof.
A stepped hydraulic plunger 87 having 7b is movably fitted. A plug 25 is press-fitted and fixed to the open end of the hole 24, whereby a hydraulic chamber 18 is formed in the hole 24 between the other end of the hydraulic plunger 87 and the plug 25. The hydraulic chamber 18 is connected to a hydraulic source (oil pump) 100 shown in FIG.
And a switching valve 101. A spring 87a is stretched between the large diameter portion of the hydraulic plunger 87 and the step portion of the hole 24, whereby the hydraulic plunger 87 is constantly biased toward the plug 25. Hydraulic chamber 1
When the hydraulic pressure from the hydraulic pressure source 100 is not applied to the hydraulic plunger 8, the hydraulic plunger 87 is urged rightward in the figure by a spring 87 a and the other end is opened as shown in FIG.
Abuts against a snap ring 89 fitted on the inner surface of the check ball 85, and the tip of the pin portion 87b is separated from the check ball 85. When the hydraulic pressure from the hydraulic pressure source 100 is applied to the hydraulic chamber 18, the hydraulic plunger 87 moves to the left in the drawing against the spring 87a as shown in FIG.
7b moves the check ball 85 against the spring 86, and connects the pressure chamber 82 and the reservoir chamber 83.
The hydraulic plunger 87 and the spring 87a are
The release mechanism of the present invention is configured.

A hole 27 is formed in the cylinder head 2 between the holes 22 and 23 in parallel. At the bottom of the hole 27, a through hole communicating with the small diameter portion of the hole 24 is formed, and a communication hole communicating with the reservoir chamber 83 is formed. The hole 27 has a timing control shaft 9.
0 is movably inserted. The timing control shaft 90 has a protruding portion extending toward the rocker arm 4 at one end, and a control portion 90 that penetrates a through hole at the other end and can protrude into a small diameter portion of the hole 24.
a. A control shaft spring 92 is stretched between the bottom of the hole 27 and the timing control shaft 90 so that the timing control shaft 90 is engaged with a snap ring 93 fitted on the inner periphery of the opening end of the hole 27. Is always urged toward the rocker arm 4. As shown in FIG.
An adjusting screw 91 is provided between the portions of the rocker arm 4 where the concave portions 41 and 43 are formed, and the cam follower portion 44 of the rocker arm 4 is connected to the base circle 1 of the cam 1a.
In a state in which the adjustment screw 91 is in sliding contact with b, one end spherical portion of the adjustment screw 91 is in contact with one end protrusion of the timing control shaft 90. As a result, when the cam 1a slides on the cam follower portion 44 of the rocker arm 4 and the rocker arm 4 is swung, the timing control shaft 90 is opposed to the control shaft spring 92 by the adjusting screw 91 so that the inside of the hole 27 is at the bottom. The control portion 90 a protrudes into the small diameter portion of the hole 24. The hydraulic plunger 87 is engaged with the control portion 90a on the outer periphery of the pin portion 87b of the hydraulic plunger 87.
A flange portion 87c for restricting the movement of the head is formed.
Incidentally, the flange portion 87c, the timing control shaft 90, the control shaft spring 92, etc.
This constitutes the timing control mechanism of the present invention.

The operation of this embodiment having the above configuration will be described below.

4 and 6, when the hydraulic pressure from the hydraulic pressure source 100 is not applied to the hydraulic chamber 18 (the switching valve 1).
01 when the hydraulic chamber 18 communicates with the oil sump)
6, the hydraulic plunger 87 is in the position shown in FIG. 6 and the position shown by the broken line in FIG. 4 by the urging force of the spring 87a, and the communication between the pressure chamber 82 and the reservoir chamber 83 is interrupted by the check ball 85. is there. Therefore, the movable column 7 is immovably held with respect to the body 81 by the pressure oil in the pressure chamber 82. In this state, when the cam 1a slides on the cam follower portion 44 to push down the rocker arm 4 by the rotation of the camshaft 1, the rocker arm 4 is provided on the supporting portion between the concave portion 43 and the pin 72, that is, on the rocker arm 4. Adjustment screw 42
As shown by the broken line in FIG. 4, the rocker arm 4 is swung about a swing fulcrum B near the contact portion (action point C) between the end 42a of the intake valve 3 and the shaft end 32a of the intake valve 3. Thereby, the intake valve 3 opens and closes the intake hole 21 with the lift amount (high lift) of L2. At this time, since the fixed support 6 is located with the swing support B interposed therebetween with respect to the action point C, the swing of the rocker arm 4 causes the concave portion 41 to separate from the joint portion 61 of the fixed support 6, that is, to support the rocker arm 4. It will be the direction to be released.
Therefore, the swing of the rocker arm 4 is not restricted by the fixed support 6.

Also, during the above-described high lift, even if the hydraulic pressure from the hydraulic pressure source 100 is applied to the hydraulic chamber 18, the timing control shaft 90 is pushed down by the adjusting screw 91 provided on the rocker arm 4,
Since the control portion 90a engages with the flange portion 87c of the hydraulic plunger 87 and restricts the movement of the hydraulic plunger 87 as shown by a broken line in FIG. 4, the lift amount does not change during the lift. When the camshaft 1 further rotates and the lift ends, and the base circle 1b of the cam 1a slides again on the cam follower portion 44 of the rocker arm 4,
The timing control shaft 90 is pushed up by the control shaft spring 92, the engagement between the control portion 90a and the flange portion 87c is released, and the hydraulic plunger 87 is moved toward the check ball 85 against the spring 87a.

When the base circle 1b of the cam 1a is again in sliding contact with the cam follower portion 44 of the rocker arm 4, the hydraulic plunger 87 is opposed to the spring 87a by the hydraulic pressure applied to the hydraulic chamber 18 from the hydraulic source 100. When moved, the pin portion 87b moves the check ball 85 against the spring 86 as shown in FIG.
2 and the reservoir chamber 83 are communicated via a passage 84.
As a result, the pressure oil filling the pressure chamber 82 flows into the reservoir chamber 83, and the pressure due to the pressure oil acting on the other end of the movable support column 7 disappears. In this state, when the cam 1a slides on the cam follower portion 44 to push down the rocker arm 4 by the rotation of the camshaft 1, the rocker arm 4 is supported by the support portion between the concave portion 41 and the joint portion 61, that is, the rocker arm 4 The center of the swing fulcrum A, which is farther from the swing fulcrum B than the swing fulcrum B from the contact point (action point C) between the end 42a of the provided adjustment screw 42 and the shaft end 32a of the intake valve 3, is indicated by a solid line in FIG. As shown, the rocker arm 4 is swung. Thereby, the intake valve 3 opens and closes the intake hole 21 with the lift amount (low lift) of L1. At this time, the movable support 7 is movable with respect to the body 81 due to the disappearance of the pressure due to the pressurized oil. Therefore, the movable support 7 resists the urging force of the spring 9 in accordance with the swing of the rocker arm 4 as shown in FIG. The pin 72 slides or rolls on the disc portion 71 along the (lost motion) guide hole 28a. Therefore, the swing of the rocker arm 4 is not restricted by the movable support 7.

Also, even if the hydraulic chamber 18 is communicated with the oil reservoir by the switching valve 101 during the low lift described above,
The timing control shaft 90 is pushed down by the adjusting screw 91 provided on the rocker arm 4, and the control portion 90a engages with the flange portion 87c of the hydraulic plunger 87 as shown by a solid line in FIG. Is restrained from moving (returning) by the urging force, and the low lift state described above is maintained, and the lift amount does not change during the lift. When the camshaft 1 further rotates and the lift is completed, and the base circle 1b of the cam 1a slides again on the cam follower portion 44 of the rocker arm 4, the timing control shaft 90 is pushed up by the control shaft spring 92, and the control portion 90a Flange part 8
The engagement with the pressure chamber 7c is released, the hydraulic plunger 87 is returned by the spring 87a, and the check ball 85 cuts off the communication between the pressure chamber 82 and the reservoir chamber 83.

The lift of the intake valve 3 shown in FIG. 4 is illustrated in FIG. As shown in FIG. 5, by selecting the swing fulcrum A or the swing fulcrum B, the lift amount of the intake valve 3 is made variable in two stages of L1 (low lift) and L2 (high lift). Therefore, the cam 1a and the cam follower portion 4
Thus, a more reliable lift amount variable operation can be obtained with a simpler structure than that in which the lift amount of the intake valve 3 is made variable by moving the sliding contact portion (force point D) with the lift valve 4. Further, in the present embodiment, the movement of the hydraulic plunger 87 is restricted by the timing control shaft 90 in accordance with the swing of the rocker arm 4, so that the lift amount is variable during the lift. Lost motion of the moving column 7 is prevented during the low lift due to motion, and switching to the high lift is reliably prevented. As a result, during the lost motion of the movable column 7 (the state in which the movable column 7 is sunk with respect to the body 81), switching to the high lift causes the entire valve train dimensions to be inconsistent, the cam to return to the base circle, and the valve to be seated. It is possible to reliably prevent the occurrence of hitting sound or the occurrence of breakage. Moreover, only one switching valve 101 for selectively communicating the hydraulic chamber 18 with the hydraulic source 100 or the oil reservoir may be provided, and the switching valve 101 is appropriately switched according to the rotation speed and load of the internal combustion engine regardless of the lift state. Since it is only necessary to control, the increase in cost can be prevented at the same time, and the control can be simplified.

In the above embodiment, the embodiment in which the present invention is applied to the intake valve 3 has been described, but it goes without saying that the present invention can be applied to an exhaust valve. In addition, it goes without saying that the lift amount of the intake valve or the exhaust valve can be varied in multiple stages (three or more stages) by adding a movable support in addition to the movable support 7.

[0026]

As described above, according to the present invention, a rocker arm can be supported for swinging, and at least one of the pillars is provided with a movable cylinder head. The rocker arm swinging fulcrum is made variable by controlling the movement and selecting one of a plurality of pillars. The fulcrum can be made variable. As a result, cost and space can be improved as compared with the related art. In addition, there is less backlash between the constituent members than in the related art, and a more stable lift amount can be obtained.

Also, by providing a timing control mechanism that allows the support column to move only while the rocker arm is in sliding contact with the base circle of the cam, the lift amount is changed during the lift, and particularly, the lift amount is changed to the high lift during the low lift. Switching is reliably prevented. Thus, switching to the high lift during the low lift causes the entire valve train system dimensions to be inconsistent, and the occurrence of hitting noise or breakage when the cam returns to the base circle and the valve is seated is reliably prevented, and a simple operation is achieved. With this configuration, the reliability of the variable valve operating device can be improved.

[Brief description of the drawings]

FIG. 1 is a sectional view showing an embodiment of a valve train of an internal combustion engine according to the present invention.

FIG. 2 is an enlarged view of a rocker arm portion in the embodiment shown in FIG.

FIG. 3 is a top view of the rocker arm in the embodiment shown in FIG.

FIG. 4 is a sectional view showing the operation of the embodiment shown in FIG. 1;

FIG. 5 is a view showing a lift state of a valve in the embodiment shown in FIG. 1;

FIG. 6 is a cross-sectional view showing a movable support, a fixed support, a timing control mechanism, and a release mechanism in the embodiment shown in FIG.

FIG. 7 is a cross-sectional view showing a moving support, a fixed support, a timing control mechanism, and a release mechanism in the embodiment shown in FIG.

[Explanation of symbols]

Reference Signs List 1 camshaft 1a cam 2 cylinder head 3 intake valve (intake / exhaust valve) 4 rocker arm 5 variable mechanism 6 fixed support (support) 7 movable support (support) 8 hydraulic lifter (movable support) 81 body 82 pressure chamber 83 reservoir chamber ( Oil passage) 85 Check ball (one-way valve) 87 Hydraulic plunger (release mechanism, plunger) 87c Flange part (timing control mechanism) 90 Timing control shaft (timing control mechanism, control shaft) 90a Control part (timing control mechanism, Control axis) A, B Swing fulcrum

 ──────────────────────────────────────────────────続 き Continued on the front page (72) Inventor Yosuke Tateishi 2-1-1 Asahi-cho, Kariya-shi, Aichi Pref. Aisin Seiki Co., Ltd.

Claims (3)

[Claims] 1. A camshaft rotatably disposed on a cylinder head of an internal combustion engine and rotated in synchronization with a crankshaft, and integrally provided on the camshaft according to the rotation of the camshaft. A rocker arm that is swung by sliding contact with a cam to lift and open and close the intake / exhaust valve, and a variable mechanism that changes a swing fulcrum of the rocker arm, and the lift amount of the intake / exhaust valve is reduced. In a variable valve train of an internal combustion engine that is variable, the variable mechanism is
The rocker arm is attached to the cylinder head so as to be able to support the swing, and at least one of the pillars is configured to be movable to the cylinder head,
A variable valve operating device for an internal combustion engine, further comprising a timing control mechanism that allows the support column to move only while the rocker arm is in sliding contact with a base circle of the cam. 2. The fixed column, wherein the variable mechanism is mounted on the end of the rocker arm opposite to the end on the intake / exhaust valve side so as to support the rocker arm and to be immovably mounted on the cylinder head. And, it is movably attached to the cylinder head, and becomes immovable with respect to the cylinder head by holding a hydraulic pressure acting on one end thereof, and is closer to the intake / exhaust valve side than a support portion of the rocker arm by the fixed support column. And one or more movable supports capable of supporting the rocker arm, and a release for releasing the hydraulic pressure acting on one end of the movable support so that the movable support is movable with respect to the cylinder head. The timing control mechanism controls the release operation and the return operation of the release mechanism by the rocker arm of the cam. 2. The variable valve train for an internal combustion engine according to claim 1, wherein the valve is allowed only during sliding contact with the base circle. 3. A pressure chamber formed at one end of the moving post in the hole by slidably fitting the moving post into a sliding hole formed in the cylinder head; A one-way valve interposed between the oil passage formed in the cylinder head and the oil passage, and allowing only oil flow from the oil passage to the pressure chamber. A plan mounted on the cylinder head so as to be movable between a release position for pushing the one-way valve to open the valve and a return position for one end thereof being separated from the one-way valve and maintaining the one-way valve closed; A jar, the timing control mechanism is movably fitted into a control hole formed in the cylinder head, and one end thereof is urged by a spring so as to always contact the rocker arm,
A control shaft that moves in the control hole against the spring only when the rocker arm swings by the cam and engages the plunger at the other end to prevent the plunger from moving. The variable valve train for an internal combustion engine according to claim 2, wherein: