JPH0252086B2 - - Google Patents

Description

Detailed Description of the Invention A. Purpose of the Invention (1) Industrial Field of Application The present invention provides a method for controlling three or more cam followers that operate in accordance with the rotation of a camshaft when they are disconnected from each other. The present invention relates to a valve operating system for an internal combustion engine, in which a connection switching device is provided between each cam follower and includes a connection pin that is slidable between two adjacent cam followers.

(2) Conventional technology Conventionally, such a valve train has been developed, for example, by
It is known from the publication No. 19911.

(3) Problems to be Solved by the Invention In the conventional system described above, each cam follower is connected integrally when each connecting member is activated, and each cam follower is connected individually when each connecting member is in a non-activated state. Therefore, only two types of switching modes can be obtained.

The present invention has been made in view of the above circumstances, and an object of the present invention is to provide a valve train for an internal combustion engine that can perform valve train control with higher accuracy by switching the valve train switching mode to three or more types. With the goal.

B. Structure of the Invention (1) Means for Solving Problems According to the present invention, the connection switching device is configured to be able to switch between connecting and disconnecting adjacent cam followers in accordance with different sliding stroke stages. The sliding stroke of the connecting member can be controlled in multiple stages.

(2) Operation By sliding the connecting member, the connection mode of the cam followers is switched. However, the connecting member connects or does not connect adjacent cam followers depending on its stroke stage, so each cam follower It becomes possible to set the connection mode to at least three or more.

(3) Embodiments Below, embodiments of the present invention will be described with reference to the drawings. First, in FIGS. 1 and 2 showing a first embodiment of the present invention, a pair of intake valves 1a provided in an engine body (not shown) are shown. , 1b are a low-speed cam 3 and a raised portion 4 that are integrally provided with a camshaft 2 that is driven at a rotation ratio of 1/2 in synchronization with the rotation of the engine.
and a high-speed cam 5, and first, second and third rocker arms 7, 8 as cam followers pivoted on a rocker shaft 6 parallel to the camshaft 2,
9 and a connection switching device 21 provided between each rocker arm 7, 8, 9, the opening and closing operation is performed.

The camshaft 2 is rotatably arranged above the engine body, and the low speed cam 3 is connected to one of the intake valves 1.
It is integrally provided on the camshaft 2 at a position corresponding to a. A high-speed cam 5 is integrally provided on the camshaft 2 at a position corresponding to between both intake valves 1a and 1b. Moreover, the low speed cam 3 has a shape suitable for low speed operation of the engine, and the camshaft 2
The high part 3a has a relatively small amount of outward protrusion along the radial direction. In addition, the high-speed cam 5 has a shape suitable for high-speed operation of the engine,
The amount of radially outward protrusion of the camshaft 2 is made larger than the high portion 3a, and the high portion 3 is
It has a high portion 5a that spans a wider central angle range than a. Further, a perfectly circular raised portion 4 is integrally provided on the camshaft 2 at a position corresponding to the other intake valve 1b, and this raised portion 4 stops the intake valve 1b in a closed state during low-speed operation. do the work.

The rocker shaft 6 is fixedly arranged below the camshaft 2. First, second and third rocker arms 7, 8 and 9 are respectively pivotally supported on the rocker shaft 6, and the first and second rocker arms 7 and 8 are basically formed in the same shape. That is, the first and second rocker arms 7, 8 have their bases swingably supported by the rocker shaft 6 at positions corresponding to the intake valves 1a, 1b, and are extended to positions above the respective intake valves 1a, 1b. . Also the first
A cam slipper 10 that slides on the low-speed cam 3 is provided on the upper part of the rocker arm 7, and a sliding contact part 11 that can slide on the raised part 4 is provided on the upper part of the second rocker arm 8.
is provided. Further, in the first and second rocker arms 7, 8, tappet screws 12, 13 which can come into contact with the upper ends of the respective intake valves 1a, 1b are screwed so as to be able to move forward and backward at the ends located above the respective intake valves 1a, 1b. It will be worn.

On the other hand, a flange 1 is provided at the upper part of both intake valves 1a and 1b.
4, 15 are provided, and these collar parts 14,
Valve springs 16, 17 are interposed between the intake valve 15 and the engine body, and each intake valve 1a, 1b is biased toward the valve closing direction, that is, upward.

Referring also to FIG. 3, the third rocker arm 9
is pivotally supported on the rocker shaft 6 between the first and second rocker arms 7 and 8. This third rocker arm 9 connects both intake valves 1a, 1 from the rocker shaft 6.
A cam slipper 18 is provided on the upper part of the cam slipper 18, which extends slightly toward the b side and slides into contact with the high-speed cam 5.
Further, a bottomed cylindrical lifter 19 is in contact with the lower surface of the end of the third rocker arm 9, and this lifter 19 has a lifter spring 20 interposed between it and the engine body.
is urged upward by. As a result, the cam slipper 18 of the third rocker arm 9 is always in sliding contact with the high-speed cam 5.

In FIG. 4, the first to third rocker arms 7 to
9 are in sliding contact with each other, and each rocker arm 7 to
A connection switching device 21 is provided between 9 and 9.

The connection switching device 21 serves as a first connection member that can connect the first and third rocker arms 7 and 9.
A connecting pin 22, a second connecting pin 23 as a connecting member capable of connecting the third and second rocker arms 9 and 8 and abutting the first connecting pin 22 on the same axis, and both connecting pins 22, 23. a stopper 24 for regulating the movement of the connecting pins 22, 23, springs 25, 26 for urging the connecting pins 22, 23 toward the disconnecting side, and a hydraulic pressure supply means 27 for supplying hydraulic pressure to operate the connecting pins 22, 23. Equipped with.

The first locking arm 7 has a third locking arm 9.
A first guide hole 29 that opens toward the side and is parallel to the rocker shaft 6 is bored, and the first connecting pin 22 is slid into this first guide hole 29, and the closed end of the first guide hole 29 and the first 1 connection pin 2
A hydraulic chamber 30 is defined between the two. Also the first
The rocker arm 7 has an oil passage 3 that communicates with the hydraulic chamber 30.
1 is bored, and an oil passage 32 communicating with the hydraulic pressure supply means 27 is bored inside the rocker shaft 6. Furthermore, both oil passages 31 and 32 are always in communication through a communication hole 33 formed in the side wall of the rocker shaft 6, regardless of the swinging state of the first rocker arm 7.

The first connecting pin 22 has a small diameter portion 3 on the second connecting pin 23 side of the large diameter portion 34 that slides into the first guide hole 29.
5 are coaxially and integrally connected, and the large diameter portion 3
A contact protrusion 36 that can come into contact with the closed end of the first guide hole 29 coaxially protrudes from the end surface of the hydraulic chamber 30 of No. 4 . The axial length of the first connecting pin 22 is such that when the contact protrusion 36 is in contact with the closed end of the first guide hole 29, the end surface of the small diameter portion 35 is between the first and third rocker arms 7 and 9. determined to be located. Moreover, the diameter of the small diameter portion 35 is
When the rocker arm enters the third rocker arm 9, the rocking motion by the low speed cam 3 of the first rocker arm 7 and the rocking motion by the high speed cam 5 of the third rocker arm are both permitted.

A guide hole 37 corresponding to the first guide hole 29 is bored in the third rocker arm 9 between both sides thereof, and a second connecting pin 23 having a length spanning the entire length of the guide hole 37 is slidably inserted into the third rocker arm 9. be done.
Moreover, the outer diameter of the second connecting pin 23 is set to be the same as the outer diameter of the large diameter portion 34 of the first connecting pin 22.

The second rocker arm 8 has a guide hole 38 on the third rocker arm 9 side corresponding to the guide hole 37.
and a large-diameter hole 39 having a larger diameter than the guide hole 38 are coaxially bored, and the guide hole 38 and the large-diameter hole 3
A stepped portion 40 facing outward is formed between the portions 9 and 9. A disk-shaped stopper 24 having the same outer diameter as the second connecting pin 23 is slid into the guide hole 38, and a shaft portion 41 is coaxially connected to the stopper 24. A retaining ring 42 is fitted on the inner surface of the large diameter hole 39 near the outer end, and a short cylindrical regulating member 43 with a bottom is regulated by the retaining ring 42 from moving outward. Fitted. Moreover, the stopper 2 is attached to the regulating member 43.
A guide hole 4 through which the shaft portion 41 of 4 is movably inserted.
4 is drilled. Further, the large diameter hole 39 has a stepped portion 40.
A ring-shaped receiving plate 45 that can come into contact with the outer peripheral edge of the stopper 24 is movably fitted.

A spring 2 is provided between the regulating member 43 and the stopper 24.
5 is interposed, and the regulating member 43 and the receiving plate 4
A spring 26 is interposed between 5 and 5. As a result, the stopper 24, that is, the first and second connecting pins 2
2 and 23 are not in the connecting operation, the stopper 24, that is, the first and second connecting pins 22,
A spring biasing force is applied to the hydraulic chamber 23 by only the spring 25, and after the stopper 24 comes into contact with the receiving plate 45, the spring force of the springs 25 and 26 is applied to the stopper 24 and the first and second connections. pin 2
It acts on 2 and 23. In other words, the spring force acting on the stopper 24 and the first and second connecting pins 22 and 23 toward the hydraulic chamber 30 is 200 degrees, with the boundary at the position where the stopper 24 contacts the receiving plate 45 as shown in FIG. change in stages.

The hydraulic pressure supply means 27 includes a hydraulic pressure supply source 46 , regulators 47 and 48 connected in parallel to the hydraulic pressure supply source 46 via a switching valve 52 , and switches the hydraulic pressure from these regulators 47 and 48 to supply it to the oil path 32 . and a control valve 49 that can switch between a mode in which the hydraulic pressure of the oil passage 32 is released and a mode in which the oil pressure in the oil passage 32 is released. Furthermore, check valves 50 and 51 are interposed between the regulators 47 and 48 and the control valve 49, respectively.

One of the regulators 47 controls and outputs the hydraulic pressure from the hydraulic pressure supply source 46 to a relatively low pressure P1, and when this hydraulic pressure P1 is supplied to the hydraulic chamber 30, the spring force shown in FIG. It is determined to exert hydraulic pressure to move each connecting pin 22, 23 and stopper 24 toward the second rocker arm 8 side against F1. Moreover, the hydraulic pressure is
The spring force F2 is determined to be smaller than the spring force F2 in FIG. That is, when the hydraulic pressure P1 is applied to the hydraulic chamber 30, the stopper 24 moves until it comes into contact with the receiving plate 45. At this time, the first
The connecting pin 22 has only its small diameter portion 35 inserted into the guide hole 3.
Let's break into 7. Also, the other regulator 48
is to control and output the hydraulic pressure from the hydraulic pressure supply source 46 to a relatively high hydraulic pressure P2, and when this hydraulic pressure P2 is supplied to the hydraulic chamber 30, it is larger than the spring force F3 in FIG. Determined to exert hydraulic pressure. That is, each connecting pin 22,
Hydraulic pressure for moving 23 and stopper 24 against the spring force of springs 25 and 26 is obtained by supplying the hydraulic pressure P2 to hydraulic chamber 30.

Next, the operation of this embodiment will be explained. When the engine is operated at low speed, the control valve 49 controls the oil passage 31,
32, that is, the hydraulic pressure in the hydraulic chamber 30 is released. For this reason, the first and second connecting pins 22 and 23 and the stopper 24 are moved toward the hydraulic chamber 30 by the spring 25.
It is moving as much as possible to the side. In this state, the contact surfaces of the first and second connecting pins 22 and 23 are at positions corresponding to the sliding surfaces of the first and third rocker arms 7 and 9, and the second connecting pin 23 and the stopper 2
4 is the contact surface of the third and second rocker arms 9, 8.
It is located at a position corresponding to the sliding surface. Therefore, the first to third rocker arms 7 to 9 are in sliding contact with each other, and the first and second connecting pins 22 and 23 as well as the second connecting pin 23 and stopper 24 are in sliding contact with each other, so that relative angular displacement is achieved. It is possible.

When the connection switching device 21 is in the disconnected state, the first rocker arm 7 swings in response to sliding contact with the low-speed cam 3 due to the rotational operation of the camshaft 2, and one intake valve 1a is switched to the low-speed The opening/closing operation is performed at a timing and lift amount depending on the shape of the cam 3. On the other hand, the second rocker arm 8 does not swing because the raised portion 4 is perfectly circular, and the other intake valve 1b remains closed. At this time, the third rocker arm 9 swings due to sliding contact with the high-speed cam 5;
The rocking motion has no effect on the operation of both intake valves 1a, 1b.

In this way, when the engine is operating at low speed, only one intake valve 1a is opened or closed, thereby reducing fuel consumption and improving idling characteristics.

When the engine is operating at medium speed, relatively low pressure P1 is supplied to the hydraulic chamber 30 by the hydraulic pressure supply means 27. As a result, as shown in FIG. 6, the stopper 24 moves against the spring force of the spring 25 until it comes into contact with the receiving plate 45, and the first connecting pin 22 guides the small diameter portion 35 of the third rocker arm 9. The second connecting pin 23 moves until it enters the hole 37, and the second connecting pin 23 moves until a portion of the second connecting pin 23 slides into the guide hole 38 of the second rocker arm 8. Therefore, the third and second rocker arms 9, 8 are connected to each other by the second connecting pin 23, but the first and third rocker arms 7, 9 can swing relative to each other. Therefore, one intake valve 1a opens and closes at a timing and lift amount that corresponds to the shape of the low-speed cam 3, and the other intake valve 1b opens and closes at a timing and lift amount that corresponds to the shape of the high-speed cam 5. .

When the engine is operating at high speed, relatively high pressure P2 is supplied to the hydraulic chamber 30 by the hydraulic pressure supply means 27. As a result, as shown in FIG. 7, the first connecting pin 22 moves against the spring force of the springs 25 and 26 until the large diameter portion 34 slides into the guide hole 38 of the third rocker arm 9. Therefore, the first to third rocker arms 7 to 9 are integrally connected. In this state, the amount of rocking of the third rocker arm 9 that is in sliding contact with the high-speed cam 5 is the largest, so the first and second rocker arms
The rocker arms 7 and 8 swing together with the third rocker arm 9, and both intake valves 1a and 1b are opened and closed at timing and lift amount according to the shape of the high-speed cam 5.

8, 9, and 10 respectively show modifications of the first embodiment, in which the locations of the low-speed cam 3, the raised portion 4, and the high-speed cam 5 are changed.

That is, in FIG. 8, the low-speed cams 3, 3 are arranged on both sides of the high-speed cam 5, the rocker arm 9 is in sliding contact with the high-speed cam 5, and the rocker arm 7, which is in sliding contact with each low-speed cam 3, is Intake valve 1a, 1
b is brought into contact. With this arrangement, during low-speed operation, both intake valves 1a, 1b open and close at timing and lift amount depending on the shape of the low-speed cams 3, 3. Furthermore, during medium-speed operation, one intake valve 1a opens and closes at a timing and lift amount that corresponds to the shape of the low-speed cam 3, whereas the other intake valve 1b operates at a timing and lift amount that corresponds to the shape of the high-speed cam 5. It opens and closes depending on the amount of lift. Furthermore, during high-speed operation, both intake valves 1a and 1b are operated by high-speed cam 5.
It opens and closes with timing and lift amount depending on the shape of the door.

In FIG. 9, a raised portion 4 is shown on one side of the high-speed cam 5.
is arranged, and a low-speed cam 3 is arranged on the other side, a rocker arm 8 that slides on the protrusion 4 contacts one intake valve 1a, and a rocker arm 7 that slides on the low-speed cam 3 contacts the other intake valve 1b. come into contact with With this arrangement, during low-speed operation, one intake valve 1a is closed and rests, while the other intake valve 1b opens and closes at a timing and lift amount depending on the shape of the low-speed cam 3. Further, during medium-speed operation, one intake valve 1a remains closed, while the other intake valve 1b opens and closes at a timing and lift amount depending on the shape of the high-speed cam 5.
Furthermore, during high-speed operation, both intake valves 1a and 1b are opened and closed at timings and lift amounts according to the shape of the high-speed cam 5.

In FIG. 10, a high-speed cam 5 is arranged on one side of the low-speed cam 3, a protrusion 4 is arranged on the other side, and a rocker arm 9 that slides on the high-speed cam 5 contacts one intake valve 1a. , the rocker arm 8 slidingly contacts the raised portion 4 and contacts the other intake valve 1b. With this arrangement, during low-speed operation, one intake valve 1a opens and closes at a timing and lift amount depending on the shape of the high-speed cam 5, while the other intake valve 1b remains closed and at rest. Furthermore, during medium-speed operation, one intake valve 1a opens and closes at a timing and lift amount that corresponds to the shape of the high-speed cam 5, whereas the other intake valve 1b operates at a timing and lift that corresponds to the shape of the low-speed cam 3. It opens and closes depending on the amount. Furthermore, during high-speed operation, both intake valves 1a, 1
(b) both open and close at timing and lift amount depending on the shape of the high-speed cam 5.

FIG. 11 shows a second embodiment of the present invention, and parts corresponding to those in the first embodiment are given the same reference numerals.

In this second embodiment, on both sides of the third rocker arm 9 which is in sliding contact with the high-speed cam 5, there are first rocker arms 7 which are in sliding contact with the low-speed cam 3 and in contact with one of the intake valves 1a, and which are in sliding contact with the raised portion 4. A second rocker arm 8 that contacts the other intake valve 1b is disposed, and a guide hole 38 of the third rocker arm 9 is arranged.
The second connecting pin 23' that has slid into contact with the first connecting pin 2
Large diameter part 34' on the 2' side and small diameter part 3 on the stopper 24 side
5' are integrally and coaxially connected. Therefore, when relatively low pressure hydraulic pressure P1 is supplied to the hydraulic chamber 30, the first and third rocker arms 7, 9 are connected by the first connecting pin 22', but the third and second rocker arms 7, 9 are connected by the first connecting pin 22'.
The rocker arms 9 and 8 are not connected, and all the rocker arms 7 to 9 are integrally connected when relatively high-pressure hydraulic pressure P2 is supplied to the hydraulic chamber 30.

That is, during low-speed operation, one intake valve 1a opens and closes with timing and lift amount depending on the shape of the low-speed cam 3, while the other intake valve 1b remains closed and at rest; While the intake valve 1a opens and closes at a timing and lift amount depending on the shape of the high-speed cam 5, the other intake valve 1b remains closed and at rest.During high-speed operation, both intake valves 1a and 1b operate at high speed. The opening/closing operation is performed at a timing and lift amount depending on the shape of the cam 5.

As a modification of this second embodiment, the high speed cam 5
On both sides of the rocker arm 9 that is in sliding contact with the low speed cam 3, the rocker arms 7, 7 that are in sliding contact with the intake valves 1a, 1b are arranged, and on both sides of the rocker arm 9 that is in sliding contact with the high speed cam 5, Raised portion 4
The rocker arm 8 is placed in sliding contact with one intake valve 1a and the rocker arm 8 is in sliding contact with the low speed cam 3 and in contact with the other intake valve 1b. Locker arms 8 are placed on both sides of the locker arm 7 in sliding contact with the raised portion 4 and in contact with one of the intake valves 1a.
It is also possible to arrange a rocker arm 9 that is in sliding contact with the high-speed cam 5 and in contact with the other intake valve 1b.

FIG. 12 shows a third embodiment of the present invention, in which a connection switching device 53 is provided between rocker arms 7 and 9.
A connection switching device 54 is provided between the rocker arms 8 and 9.

The connection switching device 53 includes a connection pin 55 as a connection member that can connect the rocker arms 7 and 9, and a stopper 56 that restricts movement of the connection pin 55.
and springs 57 and 58.

Bottomed guide holes 58, 5 in rocker arms 7, 9
9 are coaxially bored, the connecting pin 55 is inserted into the guide hole 58, and the stopper 56 is inserted into the guide hole 59.
It is rubbed together. A hydraulic chamber 60 is formed between the closed end of the guide hole 58 and the connecting pin 55. Moreover, the connecting pin 55 has a small diameter portion 61 coaxially protruding toward the rocker arm 9 side.
As the sliding stroke of the rocker arms 7 and 9 changes in two stages, the state of connection between the rocker arms 7 and 9 is switched.

The spring 57 is connected to the stopper 56 and the guide hole 59.
The spring 58 is interposed between the closed end of the guide hole 59 and the receiving member 6 which can come into contact with the step part 62 and the stopper 56 provided facing the closed end side.
3 and the closed end of the guide hole 59. Moreover, the set load of the spring 57 is set smaller than the set load of the spring 58. Therefore, by switching and supplying two stages of high and low hydraulic pressure to the hydraulic chamber 60, the connecting pin 55 switches the sliding stroke to two stages and slides. That is, when low-pressure hydraulic pressure is supplied to the hydraulic chamber 60, the connecting pin 55 slides while contracting the spring 57 until it comes into contact with the receiving member 63, and at this time, the small diameter portion 61 simply enters the guide hole 59. Therefore, both rocker arms 7 and 9 are in a disconnected state. When high-pressure oil pressure is supplied to the hydraulic chamber 60, the connecting pin 55 moves while contracting both springs 57 and 58 until it slides into the guide hole 59, thereby connecting both the rocker arms 7 and 9.

The connection switching device 54 includes a connection pin 65 as a connection member capable of connecting the rocker arms 8 and 9, a stopper 66 that restricts movement of the connection pin 65, and a spring 67.

Both rocker arms 8 and 9 have bottomed guide holes 68,
69 is coaxially bored, and the connecting pin 65 defines a hydraulic chamber 70 between the closed end and the guide hole 6.
8, and the stopper 66 is slid into the guide hole 69. The spring 67 has the same set load as the spring 57 and is interposed between the closed end of the guide hole 69 and the stopper 66.

In this connection switching device 54, when low-pressure hydraulic pressure is supplied to the hydraulic chamber 70, the connection pin 65 is connected to the spring 6.
While contracting the rocker arms 7, the rocker arms 8 and 9 are moved until they slide into the guide holes 69, and both rocker arms 8 and 9 are connected.

Therefore, when low-pressure oil pressure is supplied from the oil passage 32 to the hydraulic chambers 60, 70, the rocker arms 8,
9 are connected, and the locking arms 7 and 9 are connected.
is in a disconnected state. Furthermore, when high pressure oil pressure is supplied from the oil passage 32 to the oil pressure chambers 60 and 70,
All rocker arms 7, 8, 9 are integrally connected.

FIG. 13 shows a fourth embodiment of the present invention, in which a connection switching device 5 is provided between rocker arms 7 and 9.
3' is provided, and a connection switching device 54' is provided between the rocker arms 8 and 9.

The connection switching device 53' includes a connection pin 55' as a connection member and springs 57, 58, and the connection switching device 54' includes a connection pin 6 as a connection member.
5' and a spring 67.

Guide holes 58 and 59 are bored in the rocker arms 7 and 9, and the guide hole 58 is provided with the guide hole 5.
A connecting pin 55' that can be slidably connected to the connecting pin 9 is slidably connected to the connecting pin 55'. Furthermore, a small diameter portion 61' is coaxially formed on the rocker arm 9 side of the connecting pin 55', and a shaft portion 55'a is coaxially protruded from the side opposite to the small diameter portion 61'. This shaft portion 55'a movably penetrates the closed end of the guide hole 58 and projects outward, and springs 57 and 58 are connected in series between the projecting end of the shaft portion 55'a and the rocker arm 7. Intervention is performed in a state in which That is, the shaft portion 5
One end of the spring 58 is brought into contact with the collar 71 fitted to the protruding end of the spring 5'a, one end of the spring 57 is brought into contact with the rocker arm 7, and the other ends of both springs 57 and 58 are brought into contact with the shaft part 55'a. The receiving plate 72 is in contact with both sides of the receiving plate 72, which is movable relative to the receiving plate 72. Further, in the middle of the guide hole 58, there is a regulating stepped portion that abuts the connecting pin 55' so that the retraction limit of the connecting pin 55' is at a position where the tip of the small diameter portion 61' corresponds to between the rocker arms 7 and 9. 7
4 is provided.

The rocker arms 8, 9 have the guide holes 58,
Guide holes 68, 69 at positions off the axis of 59
are bored coaxially with each other, and a connecting pin 65' that can be slidably fitted into the guide hole 69 is slidably fitted into the guide hole 68. This connecting pin 65' has a coaxially protruding shaft part 65'a that movably passes through the closed end of the guide hole 68, and a flange 73 fitted to the tip of the shaft part 65'a and a rocker arm. A spring 67 is interposed between the spring 67 and the spring 8. Further, a regulating step 75 is provided in the middle of the guide hole 68 to regulate the backward limit of the connecting pin 65'.

Also in this embodiment, similarly to the third embodiment described above, when low pressure hydraulic pressure is supplied to the hydraulic chambers 60, 70, the rocker arms 8, 9 are connected, and the high pressure hydraulic pressure is supplied to the hydraulic chambers 60, 70. All rocker arms 7, 8, 9 can be connected when supplied. Furthermore, there is no need for the stopper required in each of the embodiments described above, making the structure simple and easy to assemble.

Although the above embodiments have been described in relation to the intake valves 1a and 1b, the present invention can also be implemented as a valve operating device for driving exhaust valves.

C. Effects of the Invention As described above, according to the present invention, the connection switching device is configured to switch between connecting and disconnecting adjacent cam followers according to the sliding stroke stage of the connecting member. is configured to be controllable in multiple stages, so by only slightly changing the conventional structure, the valve train switching mode can be switched to three or more, and valve train control can be performed with higher precision.

[Brief explanation of the drawing]

1 to 7 show a first embodiment of the present invention, FIG. 1 is a plan view, FIG. 2 is a view taken along the arrow in FIG. 1, and FIG. 3 is a view taken along the - line in FIG. Cross section, 4th
The figure is an enlarged sectional view taken along the - line in Figure 2, Figure 5 is a characteristic diagram of the spring, Figure 6 is a sectional view corresponding to Figure 4 during medium speed operation, and Figure 7 is Figure 4 during high speed operation. The sectional views corresponding to Figs. 8, 9 and 10 are shown in Fig. 1.
A plan view corresponding to FIG. 1, FIG. 11, FIG. 12, and FIG. 13 for showing modified examples of the embodiment, respectively.
The figure shows the fourth embodiment of the second, third and fourth embodiments of the present invention.
It is a sectional view corresponding to the figure. 2... Camshaft, 7, 8, 9... Rocker arm as cam follower, 21, 53, 53',
54, 54'... Connection switching device, 22, 22', 2
3, 23', 55, 55', 65, 65'... Connection pins as connection members.

Claims (1)

[Scope of Claims] 1. In a mutually disconnected state, three or more cam followers each operating according to the rotation of the camshaft are arranged in sliding contact with each other, and between each cam follower, two adjacent cam followers are arranged. In a valve train for an internal combustion engine that is provided with a connection switching device that includes a connection member that is slidable across cam followers, the connection switching device connects and disconnects adjacent cam followers according to different sliding stroke stages. 1. A valve train for an internal combustion engine, characterized in that the sliding stroke of a connecting member formed to be switchable can be controlled in multiple stages. 2. The connection switching device includes a hydraulic pressure supply means that can switch and supply high hydraulic pressure and low hydraulic pressure to one end of the connection member, and a spring that elastically biases the connection member toward the other end against the hydraulic pressure. A valve train for an internal combustion engine according to claim 1, further comprising: a valve train for an internal combustion engine;