JPH0543848B2 - - Google Patents

Description

Detailed Description of the Invention A. Purpose of the Invention (1) Industrial Field of Application The present invention provides a hydraulically operated valve that can change the operating state of an intake valve or an exhaust valve by changing oil pressure according to the operating state of an engine. The present invention relates to a valve train for an internal combustion engine, which is equipped with an operating state changing means.

(2) Prior Art Conventionally, in such a valve operating system, an oil passage for supplying hydraulic oil to a valve operating state changing means is arranged in such a manner that the valve operating state changing means is particularly disposed in a cylinder head.
It is provided as a common oil supply path with the oil supply system for each sliding contact part (for example, cam journal part, cam slipper part, etc.) in the cylinder head.

(3) Problems to be Solved by the Invention However, in the conventional oil supply system described above, the fluctuation range of oil pressure is relatively large due to the influence of the rotational speed of the internal combustion engine, oil temperature, etc. There is a risk that variations may occur, which may adversely affect driving performance. Furthermore, in order to ensure accurate operation of the valve operating state changing means, it is necessary to prevent dust from being mixed into the hydraulic fluid supplied to the valve operating state changing means. Since the oil supply system for each sliding contact part in the cylinder head is not particularly provided with an oil filter after the oil pump, the valve operation state is It is necessary to provide a special oil filter for the changing means, which increases the cost accordingly.

The present invention was proposed in view of the above circumstances.
It is possible to supply hydraulic oil to the valve operating state changing means with stable hydraulic pressure, and it is possible to avoid installing a dedicated oil filter for the valve operating state changing means, and the design is different from that of a conventional internal combustion engine. An object of the present invention is to provide a valve train for an internal combustion engine that is easy to change.

B. Structure of the Invention (1) Means for Solving the Problems In order to achieve the above object, the present invention provides a structure in which first and second rocker arms, each having an arm that abuts the upper end of an intake valve or an exhaust valve, share a common support shaft. A camshaft is pivotably supported on the engine and rotates in accordance with the operation of the engine, and the camshaft is provided with at least a cam that slides into contact with either one of the first and second rocker arms. A hydraulic engagement mechanism having a plunger which is movably fitted and which can be inserted into and removed from the other, and a hydraulic pressure chamber for applying hydraulic pressure to the plunger allows the first and second rocker arms to be connected to each other. A valve train for an internal combustion engine, which is configured to removably engage the
A first oil passage connected to the discharge port of the oil pump via an oil filter and a second oil passage connected to the hydraulic action chamber are connected to a main gear drilled in the engine body and extending approximately along the axis of the crankshaft. It is characterized by branching independently from different positions of the rari.

(2) Effect According to the above configuration, the operating state of the valve is controlled to be changed in response to the engine operating state by the hydraulic engagement mechanism using a plunger that directly engages and disengages the first and second rocker arms. be done.

In addition, since hydraulic oil is supplied to the hydraulic chamber of the hydraulic engagement mechanism through the second oil passage from the main gear rally, which extends substantially along the crankshaft axis and has a relatively large capacity, stable hydraulic pressure is always maintained. The plunger of the hydraulic engagement mechanism can be operated accurately, and the main gear is supplied with hydraulic oil discharged from the oil pump and purified by the oil filter through the first oil path.
Clean hydraulic oil can always be supplied to the hydraulic action chamber without providing a dedicated oil filter for the hydraulic engagement mechanism.

Furthermore, the first oil passage on the oil pump side and the second oil passage on the hydraulic engagement mechanism side are independently branched from different positions of the main gear rally, which extends relatively long substantially along the crankshaft axis. The connection positions of both oil passages to the main gear rally can be selected independently of each other, and the degree of freedom in selection is also increased. For example, the second oil passage on the hydraulic engagement mechanism side is connected to the first oil passage on the oil pump side ( This first oil passage should be located at a position where it can be easily connected to the hydraulic engagement mechanism in the cylinder head, regardless of the connection position to the main gear rally (there are restrictions on the connection position to the main gear rally due to the position of the oil pump and oil filter, etc.). It can be connected to the main gear.

(3) Embodiment Hereinafter, an embodiment of the present invention will be explained with reference to the drawings.First, in FIGS. It is fitted in the cylinder head 4 of each cylinder 2 so that it can move freely.
A pair of intake ports 6 that individually communicate with a plurality of intake ports 5 and adjacent to each other, and a pair of exhaust ports 8 that individually communicate with and adjoin a plurality of exhaust ports 7, for example, a pair of exhaust ports 7, are connected to a combustion chamber 9. It is formed to open toward.

Each intake port 6 is provided with an intake valve 10a, 10b, and each exhaust port 8 is provided with an exhaust valve 11a, 11b. These valves 10a, 10b, 11a, 1
Regarding 1b, one intake valve 10a and exhaust valve 11a will be described in detail with a suffix a added thereto, while referring to FIG. For illustration purposes only.

The intake valve 10a and the exhaust valve 11a are connected to a guide tube 12 provided vertically through the cylinder head 4.
retainers 14a, 15a, cylinder head 4 and guide tubes 12a, 13, which are movably inserted into retainers 14a, 15a provided at their upper ends;
The intake port 6 and the exhaust port 8 are biased in the direction of closing by the action of valve springs 16a and 17a interposed between the valve springs 16a and 17a.

Each intake valve 10a, 10b and exhaust valve 11a,
11b operates both valves 10a and 1 according to the engine speed.
0b; a state in which both 11a and 11b operate;
A state in which only one of the valves 10a and 11a operates can be selectively switched by a mechanism described later.
The configuration of such a mechanism includes intake valves 10a and 10b.
First, the portions related to the intake valves 10a, 10b will be explained.

3 and 4, a support shaft 18 is fixedly provided at the upper part of the cylinder head 4 and extends substantially horizontally, perpendicular to the operating direction of the intake valves 10a, 10b. A first rocker arm 19 and a second rocker arm 20 are commonly pivotally supported on this support shaft 18 so as to be adjacent to each other. 1st and 2nd
The intake valves 10a, 1 are attached to the rocker arms 19, 20.
Arms 21 and 22 extending toward the 0b side are provided,
At the tips of the arms 21 and 22 are nuts 23 and 24.
Adjustment screws 25 and 26 are provided, respectively, which are screwed into each other. The tips of these adjusting screws 25 and 26 abut the upper ends of the intake valves 10a and 10b, respectively. Therefore, the first and second rocker arms 19, 20
When each intake valve 10a, 10b receives an axial pressing force due to the rocking motion of the valve spring 16a, 1
6b to open the corresponding intake ports 6.

A cam slipper 27 is provided on the upper surface of the first rocker arm 19, and a cam 2 is fixed to a camshaft 28 parallel to the support shaft 18 and slides on the cam slipper 27 above the first rocker arm 19.
9 is placed. This cam 29 is the camshaft 2
8, it is configured to rotate at a rotation ratio of 1/2 in synchronization with the rotation of the engine, and has a lower part 30 formed by a circumferential surface on a reference circle, and a lower part 30 formed by a circumferential surface on a reference circle, and a lower part 30 that is radially outward from the reference circle. It has a high part 31 that bulges in the direction. Therefore, the higher part 31 is the cam slipper 2.
7, the first rocker arm 19
The arm 21 of the intake valve 10a is pressed down, and the intake valve 10a
opens the intake port 6, and when the lower portion 30 is in sliding contact with the cam slipper 27 as shown in FIG. 4, the intake valve 10a is raised by the action of the valve spring 16a, and the intake port 6 is closed. On the other hand, the second locking arm 20 is not provided with a driving mechanism such as the cam slipper 27 and the cam 29 described above, and the second locking arm 20 is integrated with the first locking arm 19 only when connected to the first locking arm 19. It operates normally, and stops operating when the connection is disconnected.

A hydraulic engagement mechanism Ma is provided to change the operating state of the intake valves 10a, 10b by switching engagement and disengagement of the first rocker arm 19 and the second rocker arm 20. In this hydraulic engagement mechanism Ma, the first rocker arm 19 includes:
A cylinder hole 33 is formed in which the plunger 32 is slidably fitted and opened to the second rocker arm 20 side.
A bottomed guide hole 3 opens toward the first rocker arm 19 and allows the plunger 32 to be inserted thereinto.
4 is drilled.

A plunger 3 is located near the bottom of the cylinder hole 33.
A step portion 35 that can come into contact with the rear end surface of the plunger 32 is provided, and this step portion 35 always defines a hydraulic chamber 36 between the rear end surface of the plunger 32 and the bottom of the cylinder hole 33. . On the other hand, an oil supply passage 37 is concentrically drilled in the support shaft 18, and an annular groove 38 is provided in the first rocker arm 19 surrounding the support shaft 18, and is connected to the annular groove 38 of the hydraulic pressure chamber 36. are communicated via a passage 39. Furthermore, a communication passage 40 is bored in the support shaft 18 to communicate the annular groove 38 and the oil supply passage 37 . Therefore, the cylinder hole 33
The hydraulic pressure chamber 36 and the oil supply passage 37 are always in communication.

A through hole 41 is concentrically bored at the bottom of the guide hole 34 in the second rocker arm 20, and a guide pin 42 that contacts the tip of the plunger 32 is inserted through the through hole 41 into the guide hole 34. Ru. A disc-shaped abutment collar 43 that abuts the entire front end surface of the plunger 32 is integrally provided at the end of the guide pin 42 on the first rocker arm 19 side. Moreover, a coiled return spring 44 surrounding the guide pin 42 is provided between the bottom of the guide hole 34 and the abutting collar 43.
is interposed, and the contact flange 43 of the guide pin 42
Due to the spring force of the return spring 44, the plunger 32
is always elastically abutted against the tip surface of the In addition, a retaining ring 7 is attached to the protruding end of the guide pin 42 from the through hole 41.
5 is fitted.

In the middle of the guide hole 34, there is a first locking arm 1.
A step-shaped stopper part 45 facing the 9 side is provided, and when the abutting collar 43 comes into contact with this stopper part 45, the guide pin 42 moves in the direction away from the first rocker arm 19, that is, the plunger 32 moves. Press movement is prevented. Further, the second rocker arm 20 is provided with an air vent hole 76 that communicates the vicinity of the bottom of the guide hole 34 with the outside, and by releasing or suctioning air from this air vent hole 76, the guide pin 42, that is, the plunger 32 is removed. Movement becomes smoother.

A set spring 46 is wound around the second rocker arm 20, and this set spring 46 biases the second rocker arm 20 toward the intake valve 10a with a spring force smaller than that of the valve spring 16b. Therefore, even in the rest state, the second rocker arm 20 does not swing due to engine vibrations, and always maintains a posture in which the adjusting screw 26 is in contact with the upper end of the intake valve 10b.

At both open end portions of the cylinder hole 33 and the guide hole 34, the first and second rocker arms 19, 20
A gap 47 is provided between the opposing surfaces of both holes 33 and 34 along the axial direction, so that when the second rocker arm 20 is at rest, the plunger 32 and the abutting collar 43 of the guide pin 42 come into contact with each other. The contact position is between the above
47.

Referring again to FIG. 2, the intake valve 1 as described above is
The configuration regarding 0a and 10b includes exhaust valves 11a and 1
The same applies to 1b, and one exhaust valve 11b
A first rocker arm 48 that drives the other exhaust valve 11a, and a second rocker arm 49 that drives the other exhaust valve 11a.
The first rocker arm 4 is commonly pivotally supported on a support shaft 50.
8 is provided with a cam slipper 52 that comes into sliding contact with the cam 51. Further, although not shown, a hydraulic engagement mechanism for connecting or uncoupling the first rocker arm 48 and the second rocker arm 49 to change the operating state of the exhaust valves 11a, 11b is provided for the intake valve 10.
It is exactly the same as that regarding a and 10b.

The oil supply path 37 of the support shaft 18 and the oil supply path 53 of the support shaft 50 are commonly connected to an oil path pipe 54 disposed between both the support shafts 18 and 50, and this oil path pipe 54 is further connected to the engine. It is connected to a hydraulic switching valve 55 disposed close to the main body 1.

The hydraulic switching valve 55 is a 3-port 2-position switching valve, and the communication state between the pressure oil distribution passage 56 to which the oil pass pipe 54 is connected, the pressure oil inlet passage 57 and the pressure oil outlet passage 58 is a pair of spool valves. Switching is effected by axial movement of the valve stem 61 with bodies 59, 60. That is, the valve stem 61 is connected to the valve body 6.
It is movably inserted into a valve hole 63 bored in the valve hole 63, and a right valve hole portion 6
A valve chamber 66 is provided, which has a larger diameter than the valve chambers 4 and 65 and is always in communication with the pressure oil distribution passage 56. The spool valve bodies 59 and 60 are fixed to the valve shaft 61 at an interval shorter than the axial length of the valve chamber 66. This results in
One spool valve body 59 is connected to the valve chamber 6 of the left valve hole portion 64.
6, the other spool valve body 60 is positioned within the valve chamber 66 so that the valve chamber 66 and the right valve hole 65 communicate with each other, and the other spool valve body 60
When the opening end of the right valve hole portion 65 to the valve chamber 66 is closed, one spool valve body 59 is located within the valve chamber 66, and the valve chamber 66 and the left valve hole portion 64 communicate with each other. The end of the right valve hole 65 opposite to the valve chamber 66 is closed with a cap 67, and between the cap 67 and the right end of the valve shaft 61, the valve shaft 61 is moved leftward, that is, A spring 68 is interposed to bias the left valve hole portion 64 in a direction to close it with the spool valve body 59. Also, the valve stem 6
1 has an insulator 69 attached to the valve body 62.
The actuator 70 is connected to the actuator 70 via the actuator 70 . This actuator 70 is actuated when the detected value of an engine speed detection sensor (not shown) reaches a preset value, and the valve shaft 61 is thereby moved against the spring force of the spring 68, and the left valve hole is moved. 64
is communicated with the valve chamber 66.

The left valve hole portion 64 is communicated with a pressure oil inlet passage 57, and an accumulator chamber 71 is communicated in the middle of this pressure oil inlet passage 57. Accumulator room 7
1 is biased by a spring 73 in the direction of contracting the accumulator chamber 71. Therefore, when the left valve hole 64 communicates with the valve chamber 66, pressure oil is quickly supplied. It will be done. Furthermore, a temperature sensor 74 is provided in the middle of the pressure oil inlet passage 57, and when the temperature detected by this temperature sensor 74 is less than a set value, the actuator is activated regardless of the signal from the engine speed detection sensor. 70 is configured to be inactive.
This is because when the temperature of the pressure oil is too low, its viscosity is high and the movement of the plunger 32 becomes unsmooth. It is possible to prevent the plunger 32 from catching on the opening edge of the guide hole 34 in the second rocker arm 20 and causing the second rocker arm 20 to move unnecessarily.

Referring to FIG. 5, the pressure oil inlet passage 57 is formed in the engine body 1 to supply lubricating oil to the main parts of the engine body 1, such as the crankshaft 80, and extends approximately along the axis of the crankshaft 80. It is connected to a branch oil passage 82 as a second oil passage branched from the long existing main gear rally 81 . Further, a discharge oil passage 100 as a first oil passage connected to a discharge port of an oil pump 83 via an existing oil filter 85 is branched from the main gear rally 81 . Therefore, both oil passages 8 in the main gear rally 81
As is clear from FIG. 5, the 2,100 branch connection positions are selected at different positions separated from each other in the axial direction of the crankshaft. Further, another oil supply passage 84 that does not pass through the oil filter 85 extends from the oil pump 83, and the lubricating oil from this oil supply passage 84 is applied to the sliding surfaces of the cam journals 29, 51 and the cam slippers 27, 52, etc. Refueled.

Next, the operation of this embodiment will be explained.
Since intake valves 10a and 11b operate in the same way, only the operation of intake valves 10a and 10b will be described below.
First, when the engine speed has not reached the set value, the actuator 70 is not operating, and therefore the oil supply path 37 is connected to the oil path pipe 54, the pressure oil distribution path 56, and the valve, as shown in FIG. room 6
6 and the right valve hole 65 to the pressure oil outlet passage 58, and the hydraulic action chamber 36 of the cylinder hole 33.
Hydraulic pressure is not applied. Therefore, the plunger 32 is positioned in the cylinder hole 33 by the spring force of the return spring 44, and the first and second rocker arms 19, 20 are disengaged from each other. As a result, the first rocker arm 19
As shown in FIG. 4, when the lower part 30 of the cam 29 is in sliding contact with the cam slipper 27, the intake valve 10a is raised to close the intake port 6, and the higher part 31 of the cam 29 is in sliding contact with the cam slipper 27. As shown in Figure 6, when the cam slipper 27 comes into sliding contact with the intake valve 10
Press down on a to open the intake port 6. In this manner, the first rocker arm 19 swings in response to the rotation of the cam 29, and only one intake valve 10a opens and closes. During this time, the other intake valve 10b remains inactive, and the guide hole 3 of the second rocker arm 20
The abutting collar 43 of the guide pin 42 inserted into the guide pin 4 is in sliding contact with the tip end surface of the plunger 32 within a gap 47. Therefore, even if only the first rocker arm 19 swings, the plunger 32 and the guide pin 4
The tip of the guide pin 2 does not catch on the opening edges of the guide hole 34 and the cylinder hole 33, and the tip of the plunger 32 and the guide pin 4 do not catch on the opening edges of the guide hole 34 and the cylinder hole 33.
2 damage is reliably prevented.

Next, assume that the engine speed exceeds the set value and the pressure oil temperature also exceeds the set value. In this case, the actuator 70 acts to
moves, the valve chamber 66 communicates with the left valve hole 64, and therefore, pressure oil acts on the hydraulic pressure chamber 36 of the cylinder hole 33 in the first rocker arm 19. As a result, the plunger 32 is pushed out against the spring force of the return spring 44. At this time, since the second rocker arm 20 is always positioned on the intake valve 10b side by the set spring 46, the plunger 32 enters into the guide hole 34 while pressing the guide pin 42, and moves until the contact collar 43 contacts the stopper portion 45, and the first and second rocker arms 19, 20 are integrated. As a result, the first and second rocker arms 1
9 and 20 begin to swing together, and both intake valves 10
a and 10b open and close in synchronization. In reality, when the plunger 32 is pushed into the guide hole 34 even slightly, both rocker arms 19, 2
0 starts an integral rocking motion.

When the engine speed falls below the set value, the operation of the actuator 70 is stopped, and in response, the valve shaft 61 is moved by the spring force of the spring 68, and the left valve hole 64 is closed by the spool valve body 59. At the same time, the right valve hole portion 65 is opened. Thereby, the oil supply passage 37 is communicated with the pressure oil outlet passage 58,
The hydraulic pressure in the hydraulic chamber 36 in the cylinder hole 33 suddenly decreases, and the plunger 32 is returned to the cylinder hole 33 by a return spring 44 via the guide pin 42.
A force is applied in the direction of pushing inward. For this reason,
A minute period of time during which the lower part 30 of the cam 29 slides into contact with the cam slipper 27, the axes of the cylinder hole 33 and the guide hole 34 coincide, and the frictional force between the plunger 32 and the inner surface of the guide hole 34 becomes lower than the spring force of the return spring 44. Inside, the plunger 32 is pressed by the guide pin 42 and pushed into the cylinder hole 33. The movement of the plunger 32 is completed when the rear end surface contacts the stepped portion 35, and at that time, the contact surface between the front end surface of the plunger 32 and the contact collar 43 of the guide pin 42 is connected to the first and second rocker arms 19. , for 20 minutes
It is located within 47. In this way, the first
Then, the engagement state of the second rocker arms 19 and 20 is released, and while the first rocker arm 19 swings in accordance with the rotational movement of the cam 29, the second rocker arm 20 becomes in a resting state.

Note that the return direction movement of the plunger 32 to the cylinder hole 33 may occur depending on the spring force of the return spring 44.
There may be cases where sliding contact of the lower part 30 with the lower part 30 is not completed within the time required. However, even if the cam 29 rotates several times and the return direction movement of the plunger 32 is completed, the time required for the several rotations of the cam 29 is extremely short, so you may feel something strange when the vehicle is actually running. I can't feel it.

The hydraulic oil is supplied to the hydraulic engagement mechanism Ma by branching from the main gear rally 81, which is close to the discharge port of the oil pump 83 and therefore has the highest oil pressure and a sufficient flow rate. Fluctuation range of oil pressure due to the influence of engine speed, oil temperature, etc. is suppressed to a small extent, and therefore the operation of the hydraulic engagement mechanism Ma is stabilized, and driving performance can be improved.
Further, the oil filter 85 has been provided conventionally, and there is no need to provide a new oil filter for the hydraulic engagement mechanism Ma, which is advantageous in terms of cost and quality, and maintenance is also simplified. Moreover, the main gear rally 81 of the branch oil passage 82
Branching out requires only slight changes in the structure of conventional internal combustion engines and therefore does not significantly increase production costs.

In this embodiment, a cam slipper 27 is provided on the first rocker arm 19, and by sliding contact with the cam 29, the first
Although the rocker arm 19 is driven to swing, a cam slipper may be provided on the second rocker arm 20 so that the second rocker arm 20 is driven to swing with the second rocker arm 20 on the normally moving side. However, when the second rocker arm 20 is driven to swing, the first and second rocker arms 19 and 20 have approximately the same weight, whereas the first rocker arm 19 and 20 have approximately the same weight as in the above embodiment. When set to the constantly moving side, it is possible to significantly reduce the weight of the second rocker arm 20, and the weight of the first rocker arm 20 can be significantly reduced.
The total weight of the second rocker arms 19 and 20 can also be reduced. In addition, when a slipper is provided on the second rocker arm 20, the first rocker arm 19 on the rest side is always connected to the intake valve 1 during oil pressure switching.
It is located on the 0a side, and is connected to the passage 39 and the communication passage 40.
The annular groove 38 for allowing the positional deviation between the passage 39 and the communication passage 40 is not required.

C. Effects of the Invention As described above, according to the present invention, a plunger that can be slidably fitted into one of the first and second rocker arms and removably inserted into the other;
Since the first and second rocker arms are removably engaged with each other by a hydraulic engagement mechanism having a hydraulic pressure chamber for applying hydraulic pressure to the plunger, this plunger type hydraulic engagement mechanism Accordingly, the operating state of the valve can be changed and controlled in accordance with the engine operating state with good response.

In addition, hydraulic oil is supplied to the hydraulic chamber of the hydraulic engagement mechanism through the second oil passage from the main gear rally, which extends substantially along the crankshaft axis and has a relatively large capacity, so that the hydraulic pressure is always stable. The plunger of the hydraulic engagement mechanism can be operated accurately, and the main gear is supplied with hydraulic oil discharged from the oil pump and purified by the oil filter through the first oil path.
Even without providing a dedicated oil filter for the hydraulic engagement mechanism, clean hydraulic oil can always be supplied to the hydraulic action chamber, and as a result, the hydraulic engagement mechanism Coupled with the effect of a plunger type that directly connects and disconnects the
This can greatly contribute to improving the operational response, and by omitting the dedicated oil filter, costs can be reduced accordingly.

Furthermore, the first oil passage on the oil pump side and the second oil passage on the hydraulic engagement mechanism side are independently branched from different positions of the main gear rally, which extends relatively long substantially along the crankshaft axis. The connection positions of both oil passages to the main gear rally can be selected independently of each other, and the degree of freedom in selection is also increased. For example, the second oil passage on the hydraulic engagement mechanism side is connected to the main gear rally of the first oil passage. Regardless of the connection position, it is possible to connect to the main gear rally at a position that allows easy communication over a short distance to the hydraulic engagement mechanism in the cylinder head. Furthermore, the branch connection of the second oil passage from the main gear gallery requires only slight modifications to the conventional internal combustion engine, and can be implemented without significantly increasing production costs.

[Brief explanation of the drawing]

The drawings show one embodiment of the present invention; FIG. 1 is a vertical sectional side view of the main part, FIG. 2 is a partially cutaway plan view of FIG. 1, and FIG. 3 is a main part of the first and second rocker arms. Fig. 4 is an enlarged cross-sectional view showing the part shown in Fig. 3.
Line sectional view, Figure 5 is a simplified diagram showing the oil supply system, Figure 6 is a simplified diagram showing the oil supply system.
The figure is a sectional view corresponding to FIG. 4, showing the operating state of the first rocker arm. Ma... Hydraulic engagement mechanism, 1... Engine body, 10
a, 10b... Intake valve, 11a, 11b... Exhaust valve, 18, 50... Support shaft, 19, 48... First rocker arm, 20, 49... Second rocker arm,
28...Camshaft, 55...Hydraulic switching valve, 8
0...Crankshaft, 81...Main gear rally, 8
2... Branch oil path as a second oil path, 83... Oil pump, 85... Oil filter, 100...
A discharge oil passage as a first oil passage.

Claims (1)

[Claims] 1 Intake valve 10a, 10b or exhaust valve 11a,
11b, each having an arm abutting the upper end of the first
and second rocker arms 19, 48; 20, 49 are swingably supported on a common support shaft 18, 50, and a camshaft 28 rotates according to the operation of the engine.
1st and 2nd rocker arm 19, 48; 20, 4
9, the first and second rocker arms 19, 4
8; It has a plunger 32 that is slidably fitted into either one of 20 and 49 and removably inserted into the other, and a hydraulic pressure chamber 36 for applying hydraulic pressure to this plunger 32. By the hydraulic engagement mechanism Ma, the first and second rocker arms 19,
48; 20, 49 is a valve operating device for an internal combustion engine configured to be removably engaged with each other, and a first oil passage 100 connected to a discharge port of an oil pump 83 via an oil filter 85; , the second oil passage 82 connected to the hydraulic pressure chamber 36 is branched independently from different positions of the main gear rally 81, which is bored in the engine body 1 and extends substantially along the axis of the crankshaft 80. A valve train for an internal combustion engine.