JP3023980B2 - Valve train for internal combustion engine - Google Patents

Description

Description: BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a valve operating device for an internal combustion engine, and more particularly to a device for switching a valve lift characteristic between a low engine speed and a high engine speed.

2. Description of the Related Art Conventionally, the lift characteristics of intake valves or exhaust valves are made different depending on the operation state in order to achieve both a torque at low to medium speed operation and an increase in output at high speed operation. A system for controlling the displacement is known (see, for example, JP-A-63-154810).

To explain this, a rocker arm for low speed whose swinging tip contacts the valve and a rocker arm for high speed that is adjacent to one side of the rocker arm for low speed and has no contact portion with the valve are rocked on a common rocker shaft. Supported as possible,
The low-speed rocker arm is in sliding contact with a low-speed cam, and the high-speed rocker arm is in sliding contact with a high-speed cam having a profile in which the valve opening angle or valve lift is larger than that of the low-speed cam.

Furthermore, in a direction parallel to the rocker shaft at a rocking portion separated from the rocker shaft by a predetermined distance, two rocker arms are connected by a piston responsive to the operating oil pressure being fitted into or coming out of the guide hole. The connection is released.

The piston is formed so as to be able to expand and contract in the extension direction by a built-in spring member, and its movement is regulated or released by a timing plate actuated by control means. The so-called knock phenomenon caused by the operation delay of the hydraulic circuit is prevented from occurring.

However, in the conventional valve gear, the piston is composed of a cylindrical connecting body and a bottomed cylindrical pressing body, and the piston is connected by a spring member housed therein. Since the body and the pressing body are biased so as to be able to expand and contract with each other in the extending direction, the length of the piston is inevitably increased. Therefore, the width of the entire low-speed rocker arm for accommodating the piston becomes large, and layout on the cylinder head becomes difficult.

In addition, as the length of the piston increases, the mass of the piston increases and the movement responsiveness in the guide hole decreases, and malfunction occurs during the switching movement of the piston, causing damage and abnormal wear of the piston.

Furthermore, the structure of the piston which requires high processing accuracy is complicated, the manufacturing and assembling operations are complicated, and the cost is inevitably increased.

Means for Solving the Problems The present invention has been devised in view of the aforementioned conventional problems, and the invention according to claim 1 comprises a high-speed cam and a low-speed cam that rotate synchronously with an engine, and a base end. The main rocker arm is pivotally supported by a rocker shaft and swings with the rotation of the one side cam to open an intake valve or an exhaust valve, and is swingable relative to the main rocker arm. A sub-rocker arm slidably in contact with the cam on the other side, and a piston slidably and hydraulically in first and second guide holes provided on opposite sides of the main rocker arm and the sub-rocker arm. Means for connecting or disconnecting the main rocker arm and the sub rocker arm in accordance with the engine operating condition, and controlling the movement timing of the piston when the connection means is disconnected. And a control mechanism, wherein the control mechanism slides in the second guide hole formed in the sub rocker arm to move the piston into the first guide hole of the main rocker arm. A plunger for retreating, a main rocker arm rotatably supporting the second guide hole in a radial direction and swinging in an axial direction, and a front end portion of the plunger being moved by a spring member in the second guide hole. A control lever for restricting pressing and formed on the outer peripheral surface of the plunger, and when the piston moves and fits into the first guide hole during the base circle of the two cams, the tip of the control lever is engaged. An engagement groove for regulating movement of the plunger;
The main rocker arm further includes: an application unit configured to apply a swinging power to the control lever in the axial direction of the guide hole.When the connection of the connection unit is released, during the cam lift of one of the two cams, The control lever is rotated to separate from the second guide hole in the radial direction, and the control lever is swung in the axial direction of the second guide hole by the applying means to be in a regulation standby state.

According to a second aspect of the present invention, a high-speed cam and a low-speed cam that rotate synchronously with the engine, a base end portion of which is pivotally supported by a rocker shaft and swings with the rotation of the one side cam. A main rocker arm for opening an intake valve or an exhaust valve by swinging, a sub rocker arm provided to be swingable relative to the main rocker arm, and swinging by sliding contact with the cam on the other side; and the main rocker arm and the sub rocker arm. Connecting means for connecting or disconnecting the main rocker arm and the sub rocker arm in accordance with the operating state of the engine by means of pistons sliding through first and second guide holes in the opposite side portions of the main rocker through hydraulic pressure; A control mechanism for controlling the movement timing of the piston when the means is disconnected from the control means. A plunger for sliding the piston back into the first guide hole of the main rocker arm by sliding in the second guide hole formed in the main rocker arm; A control lever that is swingably supported in the axial direction and has a distal end engaged with an engagement groove formed in the distal end of the plunger by a spring member to restrict movement of the piston in the second guide hole direction; Formed on the outer peripheral surface of the piston, when the piston moves and fits into the first guide hole at the time of the base circle of the two cams, the distal end of the control lever engages to regulate the movement of the piston. An annular locking groove, and an applying means provided on the main rocker arm for applying an oscillating force to the control lever in the axial direction of the guide hole. During one of the cam lifts, the control lever rotates to separate radially from between the two guide holes, and the control lever is swung in the axial direction of the guide hole by the applying means to be in a regulation standby state. It is characterized by:

Operation According to the present invention having the above-described configuration, by using the above-described configuration for the control mechanism, the piston itself can be made simpler and shorter, and the width of the main rocker arm can be made as small as possible. Further, as the piston becomes shorter, the mass of the piston becomes sufficiently small.

Further, it is needless to say that the control mechanism can prevent the so-called rattling phenomenon of the piston.

Embodiment Hereinafter, a first embodiment of the present invention will be described in detail with reference to FIGS. This embodiment is applied to an internal combustion engine equipped with two valves having the same function for one cylinder (either an intake valve or an exhaust valve, and the illustrated one is an intake valve). Is shown.

That is, each cylinder is provided with a single main rocker arm 1 corresponding to the two intake valves 3, 3, and the main rocker arm 1 has a main rocker shaft 4 whose base end 1a is common to each cylinder. , While being pivotally supported by the cylinder head, the tip 1b is in contact with the stem top of the intake valves 3,3.

The main rocker arm 1 has a substantially rectangular planar shape, and a roller 9 is rotatably provided on a shaft 7 through a needle bearing 8 in a rectangular opening 6 on one side. The low speed cam 10 of the camshaft that rotates at a synchronous speed of / 2 is brought into rolling contact with the camshaft. The sub-rocker arm 2 is provided in the elongated opening 11 formed on the other side opposite to the opening 6. The base end of the sub rocker arm 2 is rotatably connected to the main rocker arm 2 via a sub rocker shaft 12. The sub rocker shaft 12 is slidably fitted into a hole 13 formed in the sub rocker arm 2, while being press fitted into a hole 14 formed in each main rocker arm 1.

The sub rocker arm 2 does not have a portion that comes into contact with the intake valve 3, and a cam follower portion 16 that is in sliding contact with the high-speed cam 15 is formed at the tip of the sub-rocker arm 2 so as to protrude in an arc shape. A lost motion spring 17 that presses against the high-speed cam 15 is interposed.

Further, the main rocker arm 1 is integrally formed with a cylindrical concave portion 18 which is located immediately below the sub rocker arm 2 and has a lost motion spring 17 interposed therebetween. The lower end of the coil-shaped lost motion spring 17 is seated on the bottom plate 18a of the concave portion 18, and the upper end thereof is connected to the sub rocker arm 2 via a covered cylindrical retainer 19 which is slidably fitted in the concave portion 18.
Abuts on a follower portion 20 integrally formed with the second member.

Reference numeral 21 in the figure denotes connecting means for appropriately connecting and releasing the main rocker arm 1 and the sub rocker arm 2. The connecting means 21 is configured as shown in FIG. 1 and FIG. That is, in the side portion of the roller 9 of the main rocker arm 1, a bottomed cylindrical first guide hole 23 is formed in the width direction, and a cylindrical short piston 22 is slidably held therein. At the same time, an oil chamber 24 is defined behind the piston 22. On the other hand, the sub rocker arm 2 has the first
A second guide hole 25 having the same diameter as the guide hole 23 is formed coaxially with the guide hole 23, and a return spring in which one end of the piston 22 is supported by the retainer 30 at one end of the second guide hole 25.
A plunger 27 that urges toward the oil chamber 24 via 26 is housed. An annular engagement groove 27a is formed on the outer periphery of the plunger 27 on the head side. Then, the piston 22 is actuated by the operating oil pressure guided to the oil chamber 24 so that the first and second guide holes 22 and 2 are moved.
By fitting over step 5, the main rocker arm 1 and the sub rocker arm 2 are integrally connected. On the other hand, when the operating oil pressure is not introduced into the oil chamber 24,
Due to the spring force of the return spring 26, the piston 22 is pushed toward the oil chamber 24 via the plunger 27 and the first guide hole 23
The connection between the two rocker arms 1 and 2 is released when the rocker arm is settled in the position. A hydraulic circuit 28 for guiding the operating oil pressure to the oil chamber 24 includes an oil gallery 29 formed in the axial direction of the main rocker shaft 4 and an oil gallery 29 which passes through the radial direction of the main rocker shaft 4 and the inside of the main rocker arm 1. It comprises an oil passage 31 communicating the chamber 24 and the oil gallery 29.

The oil pressure discharged from the oil pump is guided to the oil gallery 29 via a switching valve (not shown) during a predetermined high-speed operation.
The control unit that electronically controls the operation of the switching valve
Input the engine rotation signal, cooling water temperature signal, lubricating oil temperature signal, supercharger intake pressure signal, throttle valve opening signal, etc., and suddenly fluctuate engine torque based on these detected values. Low-speed cam 10
And the high-speed cam 15 can be switched smoothly.

The low-speed cam 10 and the high-speed cam 15 adjacent thereto are integrally formed on a common camshaft, and have different shapes (sizes) so as to satisfy the valve lift characteristics required when the engine is running at a low speed and at a high speed. (Including similar shapes having different sizes). That is, the high-speed cam 15 has a profile that makes at least one of the valve lift amount and the valve opening period larger than the low-speed cam 10. Here, the valve lift amount and the valve opening period are both increased.

A control mechanism 40 is provided on the outer side of the sub rocker arm 2 for restricting or canceling the movement of the piston 22 via a plunger 27. More specifically, the control mechanism 40 controls the main rocker arm 1
A control lever 42 supported via a support pin 41 press-fitted into the support hole 1d of the main rocker shaft 4 and a hydraulic plunger 43 serving as pressing means for pressing a bent rear end 42b of the control lever 42 in the axial direction of the main rocker shaft 4. It is mainly composed of The control lever 42 is disposed between the opening 11 of the main rocker arm 1 and the outer surface of the sub rocker arm 2 and has a distal end portion 42.
a is the second through the side cutout 2a of the sub rocker arm 2.
A notch formed at the lower end of the shaft bearing portion 32 of the sub rocker arm 2 while having a central portion facing the guide hole 25.
It is located within 32a. In the lower end of this central portion, the bottom of the notch groove 44 is formed at the upper end of the main rocker shaft 4.
At 44a (see FIG. 7), the notch 1c of the base end 1a shown in FIG.
A projection 45 is provided which comes into contact therewith. further,
The control lever 42 is rotatably supported in the clockwise or counterclockwise direction in FIG. 1 by the support pin 41 inserted through the insertion hole 42c near the rear end 42b.
The projection 45 is urged by the torsion coil spring 46 wound around 41 in the direction of pressing the notch groove bottom surface 44a, and the tip portion 42a
Are biased to rotate counterclockwise in FIG.

The hydraulic plunger 43 has a sliding hole formed in a bulging portion 47 provided on one side of the base end 1a of the main rocker arm 1.
The pressure lever 43 is provided so as to be able to protrude and retract from the pressure chamber 48, and protrudes by the hydraulic pressure of a hydraulic chamber 49 provided on the rear end side. The control lever 42 is rotated clockwise in FIG. The oil pressure is supplied from the oil gallery 29 into the hydraulic chamber 49 via an oil passage 50 formed in the radial direction of the main rocker shaft 4 and in the base end 1a.

Therefore, according to this embodiment, during low-speed operation of the engine, the main rocker arm 1 swings according to the profile of the low-speed cam 10 to open and close each intake valve 3. At this time, although the sub rocker arm 2 is swung by the high-speed cam 15, the piston 22 and the plunger 27 are respectively accommodated in the guide holes 23 and 25 by the urging force of the return spring 26, and hinders the movement of the main rocker arm 1. Never.

On the other hand, when the operating oil pressure is guided to the oil chamber 24 through the oil gallery 29 and the through hole 31 at the time of high-speed operation of the engine, each piston 22 and plunger 27 oppose the spring force of the return spring 26. The piston 22 moves and each guide hole
Fit over 23,25. As a result, both rocker arms 1 and 2 swing together. Here, the high-speed cam 15
Is formed so that both the valve opening angle and the lift amount are larger than those of the low speed cam 10, so that when swinging integrally with the sub rocker arm 2, the roller 14 of the main rocker arm 1 The intake valves 3 are lifted from the cams 10, and each intake valve 3 is opened and closed according to the profile of the high-speed cam 15, so that both the opening angle and the lift amount of the valves are increased.

On the other hand, when the engine operation state shifts from the high rotation range to the low rotation range again, the hydraulic pressure guided to the oil chamber 24 by the operation of the switching valve decreases, and the elastic restoring force of the return spring 26 causes the piston 22 and the plunger 27 to return to the original state. The main rocker arm 1 is released from the position.

As a result, as shown in FIG. 9, the torque characteristics based on the profile of the low-speed cam 10 and the torque characteristics based on the profile of the high-speed cam 15 are combined, and the torque can be increased from the low rotation range to the high rotation range. .

Here, the rocker arms 1 and 2 correspond to FIGS.
As shown in the figure, at the time of low engine rotation, when the two cams 10 and 15 are in contact with the base circle,
Is rotated by the spring force of the torsion coil spring 46 with the support pin 41 as a fulcrum in the position shown in FIG. 1, that is, in the counterclockwise direction, and as shown in FIG. Has moved down to the position where it contacts. Therefore, as shown in FIG. 5 (A), the rear end face of the plunger 27 located on the side of the front end portion 42a at the front end side of the second guide hole 25 as shown in FIG.
27b is pressed.

In such a state, by a signal from the switching control means (not shown),
Oil pressure is supplied from the oil pump to the oil gallery 29,
The hydraulic pressure is introduced into the oil chamber 24, and the hydraulic pressure acts on the piston 22 to move in the direction of the second guide hole 25. However, since the plunger 27 is restricted from retreating by the control lever 42, the piston 22 is also moved. Its movement is regulated. At the same time, the hydraulic pressure is also introduced into the hydraulic chamber 49, and the hydraulic plunger 43 protrudes and moves to press the side surface of the rear end portion 42b of the control lever 42, so that the first
Attempt to rotate clockwise in the figure. In this state, when the camshaft rotates and one of the main and sub rocker arms 1 and 2 swings, the tip portion 42a of the control lever 42
However, as shown in FIG. 4, the plunger 27 is separated from the rear end face 27b. That is, for example, the sub rocker arm 2 is pushed down by the high-speed cam 15. On the other hand, the control lever 42 itself
With the swing of the main rocker arm 1, the protrusion 45 is pushed up to the notch groove bottom surface 44 a of the main rocker shaft 4,
Since the rotation in the counterclockwise direction in the figure is restricted, it is separated from the rear end face 27b. Accordingly, the movement of the plunger 27 toward the rear end of the second guide hole 25 is released.
When either of the sub rocker arms 1 and 2 is pushed down by the cams 10 and 15, the center axes of the two guide holes 23 and 25 are shifted, so that the movement of the piston 22 is restricted by the hole edge of the second guide hole 25. You.

Further, the control lever 42 has a distal end 42a separated from the plunger 27, but further has a rear end 42a attached to the hydraulic plunger 43.
As b is pressed and pivots clockwise in FIG. 1, the distal end portion 42a is pressed against the side surface of the sub rocker arm 2.

From here, when each of the cams 10 and 15 is further rotated to the base circle state, the distal end portion 42a comes into contact with the outer peripheral surface of the rear end portion of the plunger 27 as shown in FIG.
Therefore, the movement restriction of the plunger 27 by the control lever 42 is released. On the other hand, since the first and second guide holes 23 and 25 match according to the base circle state, the piston 22
As shown in FIG. 5 (C), while the plunger 27 is pressed against the spring force of the return spring 26 by the oil pressure in the oil chamber 24, the tip moves and fits into the second guide hole 25, The tip 42a of the control lever 42 is engaged with the engagement groove 2 of the plunger 27.
Engage in 7a.

As described above, since the movement of the piston 22 is released during the cam lift and the movement to the next base circle is released at the same time as the movement to the next base circle, the piston 22 can quickly move toward the second guide hole 25. A detachment phenomenon (flapping phenomenon) from the second guide hole 25 due to insufficient engagement with the second guide hole 25 can be reliably prevented. As a result, the wear and breakage of the edge of the second guide hole 25 can be prevented, and the generation of a rattling sound can be prevented.

Next, a description will be given of a timing operation of detaching the piston 22 from the second guide hole 25. That is, the piston 22 is positioned as shown in FIG.
As shown in the figure, in the state of being fitted in the first and second guide holes 23 and 25, first, a large spring force of the valve spring 3a acts on the piston 22 via the two rocker arms 1 and 2 during the cam lift. Therefore, even if the hydraulic pressure for the piston 22 is released, the piston 22 is locked and cannot move. On the other hand, at the time of the cam base circle, although the large spring force of the valve spring 3a does not act, the distal end portion 42a of the control lever 42 engages with the engagement groove 27a as described above to regulate the movement of the plunger 27.

Here, when the hydraulic pressure acting on the piston 22 is released, that is, when the introduction of the hydraulic pressure to the oil chamber 24 is interrupted by a signal for controlling the valve lift from large to small lift,
Since the introduction of hydraulic pressure to 49 is also shut off, movement of the plunger 27 by the control lever 42 is continued as described above during the base circle, but the bottom of the notch groove 44 during the cam lift.
Since the a pushes up the projection 45, the tip 42a rises from the engagement groove 27a as shown in FIG. 4, and at the same time, the pressing by the hydraulic plunger 43 is released.
1 rotates counterclockwise in FIG. 1 to ride on the outer peripheral surface of the plunger 27 (FIG. 5 (D) state).

Therefore, the movement restriction of the plunger 27 by the control lever 42 is released, whereby the piston 22 is unlocked by the spring force of the valve spring 3a when shifting to the base circle, so that the piston 22 and the plunger 27
By the spring force of the return spring 26, the piston 22 quickly moves in the direction of the first guide hole 23 until the end face of the piston 22 hits the bottom surface of the first guide hole 23.

In this way, even when the piston 22 returns to the inside of the first guide hole 23 by the return spring 26, the timing of the return movement is assured, and the piston 22 can be moved in the initial stage of transition to the base circle. As a result, the movement of the piston 22 to the first guide hole 23 becomes smooth, and a so-called knock phenomenon can be prevented.

Further, in the present embodiment, by configuring the control mechanism 40 as described above, it is possible to make the piston 22 single and short without dividing the piston 22 into a plurality.

Moreover, in the present embodiment, the sub-rocker arm 2 is connected to the main rocker arm 1 via the sub-rocker shaft 12, so that the sub-rocker arm 2 can be downsized, and the inertial mass of the valve train can be further reduced, and the rotation speed can be increased. The valve followability in the region can be improved. Further, the urging force of the lost motion spring 17 can be reduced, and the friction at the sliding contact portion between the sub rocker arm 2 and the high-speed cam 15 is reduced, so that the fuel consumption of the engine can be reduced.

Further, the main rocker arm 1 and the sub rocker arm 2 can be unitized, and the roller 9 and the cam follower portion can be formed.
The mounting accuracy between 16 can be confirmed when assembling to the cylinder head 5.

The sub-rocker arm 2 has a substantially T-shaped cross section as shown in FIGS. 5A to 5D. The sub-rocker arm 2 has a vertical piece 2b formed at the lower end of the cam follower section 16 having a narrow width. Centrally located. For this reason, as described above, when the piston 22 is fitted over each of the guide holes 23 and 25 and the arms 1 and 2 are in the connected state,
The spring load and inertia force of the valve spring 3a transmitted from the main rocker arm 1 via the piston 22
By 2b, it is received at the lower center of the cam follower section 16. Accordingly, the cam surface of the low-speed cam 10 comes into contact with the substantially center position of the upper surface (slipper surface 16a) of the cam follower portion 16, that is, the uneven load of the cam follower portion 16 on the slipper surface is prevented.

In addition, since the vertical piece 2b is formed to have a narrow width, the sub rocker arm 2 holds the vertical piece 2b with respect to the axial direction of the sub rocker shaft 12 even when the piston 22 is fitted in each of the guide holes 23 and 25. Since the sub rocker arm 2 can tilt slightly to the left and right as a center, when a force acts on the sub rocker arm 2 in the tilt direction with respect to the axial direction of the sub rocker shaft 12 due to a difference in valve clearance of each intake valve, the cam follower The part 16 also tilts. Therefore, the slipper surface 16
The contact of a with the cam surface is prevented, and uneven wear due to local excessive surface pressure is prevented.

10 to 12A and 12B show a second embodiment of the present invention. In this embodiment, an annular locking groove 22a for locking the distal end portion 42a of the control lever 42 is formed substantially at the center of the outer peripheral surface of the piston 22, while the plunger 27 is replaced by the piston 22 instead of the central engaging groove 27a. An engagement groove 27b is formed on the outer periphery of the distal end on the side. The control lever 42 is rotatably supported by the sub rocker shaft 12 instead of the support pin 41. That is,
The control lever 42 is provided in an elongated gap C formed between the inner portion of the sub rocker arm 2 and the opposing inner edge of the opening 11. The sub-rocker shaft 12 is inserted into an insertion hole 42d near the rear end 42b, and is supported by the sub-rocker shaft 12 so as to be rotatable clockwise and counterclockwise in FIGS. 12A and 12B. At the same time, the torsional coil spring 51 wound around the sub rocker shaft 12 urges the tip portion 42a, which is bent in a counterclockwise direction in the drawing, that is, in a crank shape, to rotate downward. On both sides of the control lever 42 near the insertion hole 42d, spherical protrusions 52, 5 serving as fulcrums for swinging the control lever 42 clockwise and counterclockwise in FIG.
Two are provided. Further, in a spring accommodating hole 1c drilled in the side of the opening 11 side of the main rocker shaft 1, an application means for swinging the control lever 42 counterclockwise in FIG. The compression spring 53 is mounted.

Therefore, this embodiment has a simple operation because the basic operation is the same as that of the first embodiment.

That is, when the rocker arms 1 and 2 are in contact with the base circles of the cams 10 and 15 when the engine is running at a low speed,
The control lever 42 is rotated by the torsion coil spring 51 so that the distal end 42a is rotated downward so that the engagement groove is formed as shown in FIGS. 12 and 13A.
27b, and the end portion 42a has one end face of the piston 22
Contacting 22b. Therefore, even if the piston 22 attempts to move due to the oil pressure in the oil chamber 24, the movement is restricted by the control lever. In this state, when one of the main and sub rocker arms 1 and 2 swings, the control lever 4
2 is separated from the one end face 22b of the piston 22 as described above, but at this point, since the center axes of both the guide holes 23 and 25 are shifted, the movement of the piston 22 is restricted by the hole edge of the second guide hole 25. Is done.

From here, when each of the cams 10 and 15 further rotates to the base circle state, the distal end portion 42a comes into contact with the outer peripheral surface of the piston 22 as shown in FIG. 13B, and the movement restriction of the piston 22 is released. Is done. On the other hand, since the center axes of the guide holes 23 and 25 are aligned, the piston 22 presses the plunger 27 against the spring force of the return spring 26 by the oil pressure of the oil chamber 24 as shown in FIG. At the same time as the movable lever is fitted into the guide hole 25, the control lever distal end portion 42a is locked in the locking groove 22a of the piston 22 to position the piston 22.

Therefore, as in the first embodiment, the piston 22 can move in the direction of the second guide hole 25 at the same time as the transition to the base circle, so that the piston 22 can be quickly moved to the second guide hole 25.

On the other hand, the timing of the separation of the piston 22 from the second guide hole 25 is the same as that of the first embodiment, the engine shifts from the high engine speed range to the low engine speed range, and the introduction of the oil pressure to the oil chamber 24 is cut off. At the same time, the introduction of hydraulic pressure into the hydraulic chamber 49 is also interrupted, so that the control lever 42 is urged to swing counterclockwise in FIG. 10 around the projections 52, 52 by the spring force of the compression spring 53. Here, when the cam lift state is reached, the notch groove bottom surface 44
Since a pushes up the protrusion 45, the tip end portion 42a rises from the locking groove 22a as shown in FIG. 12B, and rides on the outer peripheral surface of the piston 22 by the aforementioned counterclockwise urging force, thereby causing the sub rocker arm 2 to move vertically. It contacts the side surface of the piece 2b (see FIG. 13D). Therefore, the piston 22 by the control lever 42
Movement restriction is released, and piston 22
Moves quickly and reliably toward the first guide hole 23 by the spring force of the return spring 26.

In this embodiment, the support pins 41 as in the first embodiment are used.
And the sub-rocker shaft 12 and the projections 52, 52 are used as pivot points for the control lever 42, simplifying the overall structure and making it easy to rotate and swing the control lever 42 in the vertical and horizontal directions. Thus, it is possible to stably and reliably perform the movement restriction and the restriction release of the piston 22.

Advantageous Effects of the Invention As is apparent from the above description, according to the present invention, good switching movement timing of the piston to each guide hole can be obtained, and the connection and release operations of the main rocker arm and the sub rocker arm become smooth, The piston can be made simple and short. As a result, the width of the main rocker arm that houses the piston can be made as small as possible, and the layout on the cylinder head is facilitated.

Further, since the mass of the piston is reduced due to the miniaturization of the piston, the movement responsiveness in each guide hole is improved, and the switching control of the high-speed and low-speed cams is performed in combination with the above-mentioned improvement of the switching movement timing. Accuracy is improved and piston damage and abnormal wear are prevented.

In addition, since the structure of the piston is simplified, manufacturing and assembling operations are facilitated, and the cost can be reduced.

[Brief description of the drawings]

FIG. 1 is a plan view showing a first embodiment of the present invention, partially cut away, FIG. 2 is a sectional view taken along line AA of FIG. 1, and FIG. 3 is a sectional view taken along line BB of FIG. FIG. 4 is a first view showing the operation of this embodiment.
5A is a cross-sectional view taken along the line CC in FIG. 1, and FIGS. 5B to 5D are views showing the operation of the present embodiment. FIG. 6 is a perspective view showing a control lever, a support pin, and a torsion coil spring of the present embodiment, FIG. 7 is a perspective view of a main part of a main rocker shaft, and FIG. 8 is a partially enlarged view of a main rocker arm. 9, FIG. 9 is a valve lift characteristic diagram of the present embodiment, FIG. 10 is a plan view showing a second embodiment of the present invention with a part cut away, FIG. 11 is a sectional view taken along the line DD of FIG. Twelfth
10A is a sectional view taken along line EE of FIG. 10, FIG. 12B is a sectional view taken along line EE of FIG. 10, and FIG. 13A is a sectional view taken along line FF of FIG. FIGS. 10A to 10D show the operation of the present embodiment.
It is FF sectional drawing of FIG. DESCRIPTION OF SYMBOLS 1 ... Main rocker arm, 1a ... Base end, 1b ... Tip end, 2 ... Sub rocker arm, 3 ... Intake valve, 4 ... Main rocker shaft, 10 ... Low speed cam, 15 ... High speed Cam, 21 ... connecting means, 22 ... piston, 23, 25 ... No.
1, second guide hole, 40: control mechanism, 42: control lever,
42a: Tip, 43: Hydraulic plunger.

──────────────────────────────────────────────────続 き Continuation of front page (56) References JP-A-2-207108 (JP, A) JP-A-61-81511 (JP, A) JP-A-63-154810 (JP, A) JP-A-61-815 31613 (JP, A) JP-A-2-267307 (JP, A) (58) Fields investigated (Int. Cl. ⁷ , DB name) F01L 13/00 F01L 1/18 F01L 1/26 F02D 11/06

Claims (2)

(57) [Claims] A high-speed cam and a low-speed cam that rotate synchronously with an engine; a base end pivotally supported by a rocker shaft; and an intake valve that swings with the rotation of the one side cam. Alternatively, a main rocker arm that opens the exhaust valve, a sub rocker arm that is provided to be swingable relative to the main rocker arm, and swings by slidingly contacting the other cam.
The main rocker arm and the sub rocker arm are connected or disconnected by a piston that slides through hydraulic pressure in first and second guide holes provided on opposite sides of the main rocker arm and the sub rocker arm according to an engine operating state. In a valve operating device for an internal combustion engine, comprising: a connecting means; and a control mechanism for controlling a movement timing of a piston when the connecting means is disconnected, wherein the control mechanism is provided in a second guide hole formed in a sub rocker arm. A plunger for reciprocating the piston into the first guide hole of the main rocker arm, a plunger supported by the main rocker arm so as to be pivotable in the radial direction of the second guide hole and swingable in the axial direction, and A control lever having a distal end that presses and restricts a rear end surface of the plunger in the second guide hole by a spring member; Engagement formed on the outer peripheral surface of the lancer, wherein when the piston moves and fits into the first guide hole at the time of the base circle of the two cams, the tip of the control lever engages to regulate the movement of the plunger. A groove provided on the main rocker arm, and applying means for applying a swinging force to the control lever in the axial direction of the guide hole, wherein one of the two cams is lifted when the connecting means is disconnected. In the meantime, the control lever is rotated to be radially separated from the second guide hole, and the control lever is swung in the axial direction of the second guide hole by the applying means to be in a regulation standby state. Valve apparatus for an internal combustion engine. 2. A high-speed cam and a low-speed cam, which rotate synchronously with the engine, and a base end pivotally supported by a rocker shaft, and oscillate with rotation of the one side cam to rotate the intake valve. Alternatively, a main rocker arm that opens the exhaust valve, a sub rocker arm that is provided to be swingable relative to the main rocker arm, and swings by slidingly contacting the other cam.
The main rocker arm and the sub rocker arm are connected or disconnected by a piston that slides through hydraulic pressure in first and second guide holes provided on opposite sides of the main rocker arm and the sub rocker arm according to an engine operating state. In a valve operating device for an internal combustion engine, comprising: a connecting means; and a control mechanism for controlling a movement timing of a piston when the connecting means is disconnected, wherein the control mechanism is provided in a second guide hole formed in a sub rocker arm. And a plunger for retracting the piston into the first guide hole of the main rocker arm, and being supported by the sub rocker arm so as to be pivotable in the radial direction between the two guide holes and swingable in the axial direction, and The distal end is engaged with an engaging groove formed in the distal end of the plunger by a spring member, and is moved toward the second guide hole of the piston. And a control lever formed on the outer peripheral surface of the piston so that when the piston moves and fits into the first guide hole during the base circle of the two cams, the tip of the control lever is engaged. An annular locking groove for restricting the movement of the piston,
The main rocker arm further includes: an application unit configured to apply a swinging power to the control lever in the axial direction of the guide hole.When the connection of the connection unit is released, during the cam lift of one of the two cams, The control lever is rotated to be radially separated from between the two guide holes, and the control lever is swung in the axial direction of the guide holes by the applying means to be in a regulation standby state. Valve train.