JPH0234401Y2 - - Google Patents

Description

[Detailed description of the invention] A. Purpose of the invention (1) Industrial field of application The invention provides a system in which at least one pair of mutually adjacent intake valves or exhaust valves having the same function is arranged for one cylinder. The present invention relates to a valve operating device for an internal combustion engine that changes the operating mode of the intake valve or the exhaust valve according to the engine speed.

(2) Prior Art Conventionally, high-speed internal combustion engines are known in which a plurality of intake valves and exhaust valves are arranged for one cylinder. In such an internal combustion engine, the operating state of the engine is adjusted so that, for example, some intake valves and exhaust valves are inactive during low or medium speed operation, and all intake and exhaust valves are activated during high speed operation. By changing the operating state of the intake valve or exhaust valve accordingly, high efficiency can be obtained over the entire operating range of the engine, and fuel efficiency can be improved.

(3) Problems to be solved by the invention However, in the past, no satisfactory device has been available for solving the above problems.

The present invention was developed in view of such circumstances, and aims to provide a highly practical valve train for an internal combustion engine that can achieve highly reliable operation with a relatively simple configuration. purpose.

B. Structure of the invention (1) Means for solving the problem According to the invention, the first rocker arm and the second rocker arm, each having an arm that abuts the upper end of a pair of intake valves or exhaust valves, move in the operating direction of the valve. The first rocker arm is swingably supported on a common support shaft fixed to the engine body with an axis perpendicular to the engine body, and the first rocker arm has a cylinder hole opened toward the second rocker arm side and housing the plunger. established, second
The rocker arm is provided with a guide hole that is open toward the first rocker arm and into which the plunger can be inserted, and a hydraulic chamber defined between the bottom of the cylinder hole and the rear end of the plunger is formed in the rocker arm. It is connected to a hydraulic pressure source via a hydraulic switching valve that switches between supplying and stopping hydraulic pressure to the working chamber, and at least one of the first and second rocker arms has a cam that slides and rotates according to engine operation. An abutting cam slipper is provided.

(2) Function According to the above configuration, when the plunger is driven by the hydraulic pressure in the hydraulic action chamber and inserted into the guide hole, the first and second rocker arms are connected, and when the plunger is pulled into the cylinder hole, the first and second rocker arms are connected. Since the coupling state of the rocker arm is released, the operating mode of the first and second rocker arms, that is, the intake valve or the exhaust valve, at least one of which is driven by a cam, changes in accordance with the switching between the coupled state and the disconnected state. .

(3) Embodiment An embodiment of the present invention will be described below with reference to the drawings. First, in FIGS. 1 and 2, pistons 3 are reciprocating in a plurality of cylinders 2 of an engine body 1 in a multi-cylinder internal combustion engine. 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 an axial pressing force is applied due to the rocking movement of the valve springs 16a, 1, each intake valve 10a, 10b
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 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 in a direction radial from the reference circle. It has a high portion 31 that bulges outward. Therefore, the higher part 3
1 is in sliding contact with the cam slipper 27, the arm 21 of the first rocker arm 19 is pushed down, the intake valve 10a opens the intake port 6, and the lower position 30 is slid against the cam slipper 27 as shown in FIG. In the state of contact, 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 rocker arm 20 is not provided with drive mechanisms such as the cam slipper 27 and the cam 29 described above, and the second rocker arm 20
operates integrally with the first rocker arm 19 only when it is connected to the first rocker arm 19, and stops its operation when it is disconnected.

In order to achieve such connection and disconnection of both rocker arms 19 and 20, the first rocker arm 1
9 is a cylinder hole 33 which movably accommodates the plunger 32 and is open to the second rocker arm 20 side.
A bottomed guide hole 34 is formed in the second rocker arm 20 in correspondence with the cylinder hole 33 and opens toward the first rocker arm 19 to allow the plunger 32 to be inserted therein.

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 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 the hydraulic pressure chamber 36 and the annular groove 38 are connected to each other. aisle 3
9. 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 hydraulic pressure chamber 36 of the cylinder hole 33 and the oil supply path 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 locker arm 20, and the set spring 46 locks the second locker arm 20 with a smaller spring force than the valve spring 16b.
0 toward the intake valve 10a. Therefore, the second
Even in its rest state, the 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, and when the second rocker arm 20 is in a rest state, the plunger 32 and the abutting collar 43 of the guide pin 42 are in contact with each other. The position is set to be located in the gap 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 11a
A first rocker arm 48 that drives the exhaust valve 11b, and a second rocker arm 49 that drives the other exhaust valve 11b.
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. Furthermore, although a mechanism for connecting or disconnecting the first rocker arm 48 and the second rocker arm 49 is not shown, the intake valve 10a,
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.
The valve hole 63 is movably inserted into a valve hole 63 provided in the valve hole 63, and a pressure oil distribution passage 56, which has a larger diameter than the left and right valve holes 64 and 65, is provided in the center of the valve hole 63.
A valve chamber 66 is provided which is in constant communication with the valve chamber 66 . 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. As a result, when one spool valve body 59 closes the opening end of the left valve hole portion 64 to the valve chamber 66, the other spool valve body 60 is located within the valve chamber 66, and the valve chamber 66 and the right valve hole portion 66 are closed. When the spool valve body 60 is in communication with the valve chamber 66 and the other spool valve body 60 closes the opening end of the right valve hole portion 65 to the valve chamber 66, the one spool valve body 59 is located within the valve chamber 66 and the valve chamber 66 and the left valve hole are closed. The portion 64 communicates 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. Further, the left end portion of the valve shaft 61 is connected to an actuator 70 that is connected to the valve body 62 via an insulator 69. 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 communicates 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, so that when the left valve hole 64 communicates with the valve chamber 66, pressure oil is quickly supplied. It will be held in In addition, 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, regardless of the signal from the engine rotation speed detection sensor, Actuator 70 is configured not to actuate.
This is because, for example, when the engine body 1 is not sufficiently heated when starting the engine, and the temperature of the pressure oil is too low, the viscosity of the hydraulic oil is high, and the plunger 32 cannot move. This is to deal with the case where the plunger 32 is moved at an insufficient speed and the plunger 32 touches the opening edge of the guide hole 34 in the second rocker arm 20. It is possible to prevent the second rocker arm 20 from being caught and causing unnecessary movement.

The pressure oil inlet passage 57 is connected to an oil pump (not shown) for supplying lubricating oil to the engine, and the pressure oil outlet passage 58 is connected to an oil tank (not shown). By using lubricating oil pressure in this way,
The additional structure can be further simplified compared to the case where an oil pump is specially arranged and a hydraulic system separate from the lubrication hydraulic system is used.

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 rises to close the intake port 6, and the higher part 31 of the cam 29 is in contact with the cam slipper 27. As shown in Figure 5, when the cam slipper 27 comes into sliding contact, 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 contact flange 43 of the guide pin 42 inserted into the guide pin 4 is in sliding contact with the distal end surface of the plunger 32 within the gap 47. Therefore, even if only the first rocker arm 19 swings, the plunger 32 and the guide pin 4
The tip of the 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, in FIGS. 6, 7, and 8, it is assumed that the engine speed exceeds the set value while the pressure oil temperature is increased to exceed the set value. In this case, the actuator 70 acts to move the valve shaft 61 and the valve chamber 66 communicates with the left valve hole 64, so that the pressure oil flows into the cylinder hole 33 of the first rocker arm 19 and into the hydraulic action chamber 36. act.
As a result, the plunger 32 is pushed out against the spring force of the return spring 44. At this time, the second rocker arm 20 is moved by the set spring 46 to the intake valve 10b.
Since it is always located on the side, the lower part 3 of the cam 29
0 and the cam slipper 27 in sliding contact, the plunger 32 enters the guide hole 34 while pressing the guide pin 42, and the abutting collar 4
3 moves until it abuts against the stopper portion 45, and the first and second rocker arms 19, 20 are integrated. As a result, the first and second rocker arms 19 and 20 begin to swing together, and both intake valves 1
0a and 10b open and close in synchronization. In reality, when the plunger 32 enters 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,
Within a minute time when 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. Then, 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 as follows.
It is located within the gap 47 between the first and second rocker arms 19,20. In this way, the first
Then, the connected state of the second rocker arms 19 and 20 is released, and while the first rocker arm 19 swings according to the rotational movement of the cam 29, the second rocker arm 20 becomes in a rest 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.

In the above embodiment, the cam slipper 27 that slides into contact with the cam 29 is provided only on the first rocker arm 19,
When the first and second rocker arms 19 and 20 are not connected, the rocking motion of the second rocker arm 20, that is, the operation of one of the intake valves or the exhaust valve, is stopped. It is also possible to provide a cam stopper on each of the locking arms 20 so that each locking arm 19, 20 can be operated independently when the two locking arms 19, 20 are disconnected.

C. Effects of the invention As described above, according to the invention, the first rocker arm and the second rocker arm for opening and closing at least one pair of intake valves or exhaust valves, respectively, are connected to the plunger housed in the cylinder hole on the first rocker arm side. are connected by hydraulically driving the locker arms by fitting them into the guide holes on the second rocker arm side, and by retracting the plunger into the cylinder holes, the connected state of both rocker arms is released, and the first and second rocker arms are connected.
With a relatively simple configuration in which at least one of the rocker arms is rockingly driven by a cam, the operating mode of the intake valve or the exhaust valve can be switched with a reliable switching operation. Furthermore, since the plunger also serves as a connecting member between both rocker arms, the number of components can be reduced, making it more compact and improving responsiveness. Furthermore, since the mechanisms for coupling and uncoupling are built into both rocker arms, no extra space is required for arranging these mechanisms, and the engine can be made more compact. Such a device of the present invention can be applied to existing internal combustion engines without major design changes.

[Brief explanation of the drawing]

The drawings show one embodiment of the present invention, in which Fig. 1 is an overall longitudinal sectional side view, 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 - of Fig. 3.
A line sectional view, Figure 5 is a sectional view corresponding to Figure 4 showing the operating status of the first rocker arm, and Figure 6 is a partially cutaway view corresponding to Figure 2 showing the state when both rocker arms are connected. 7 is an enlarged cross-sectional view corresponding to FIG. 3 showing the connected state of both rocker arms in the state shown in FIG. 6, and FIG. 8 is a cross-sectional view taken along the line -- in FIG. 7. 1... Engine body, 2... Cylinder, 10a, 1
0b...Intake valve, 11a, 11b...Exhaust valve, 1
8, 50... Support shaft, 19, 48... 1st rocker arm, 20, 49... 2nd rocker arm, 21,
22... Arm, 27, 52... Cam slipper, 2
9,51...Cam, 32...Plunger, 33...
... Cylinder hole, 34 ... Guide hole, 36 ... Hydraulic action chamber, 42 ... Guide pin, 45 ... Stopper part, 55 ... Hydraulic switching valve, 76 ... Air vent hole.

Claims (1)

[Claims for Utility Model Registration] (1) In an internal combustion engine in which at least one pair of mutually adjacent intake valves or exhaust valves having the same function is arranged for one cylinder, a pair of said intake valves or exhaust valves A first rocker arm and a second rocker arm, each having an arm that abuts the upper end of the valve, are swingably supported on a common support shaft fixed to the engine body and having an axis perpendicular to the operating direction of the valve. , the first rocker arm has the second
A cylinder hole that opens toward the rocker arm side and accommodates the plunger is drilled, and a guide hole that opens toward the first rocker arm and into which the plunger can be inserted is bored in the second rocker arm. A hydraulic working chamber defined between the bottom and the rear end of the plunger is connected to a hydraulic power source via a hydraulic switching valve that switches between supplying and stopping hydraulic pressure to the working chamber, and the hydraulic working chamber is connected to a hydraulic power source through a hydraulic switching valve that switches between supplying and stopping hydraulic pressure to the working chamber. A valve operating system for an internal combustion engine, characterized in that at least one of the above is provided with a cam slipper that slides into contact with a cam that rotates according to the operation of the engine. (2) The valve operating system for an internal combustion engine according to claim 1, wherein the cam slipper is provided only on the first rocker arm. (3) The guide pin is movably housed in the guide hole and is elastically biased to come into contact with the plunger, and is provided with a stopper portion that restricts movement of the guide pin in a direction away from the first rocker arm. The internal combustion engine according to claim 1 or 2 of the utility model registration claim, characterized in that the closed end of the guide hole is provided with an air vent hole that communicates the closed end and the guide pin with the outside. Engine valve gear.